Re: The R1100RS Lectron Conversion Saga

[Karl Johnson <karljohnson@xxxxxxx>]

Dan,

Thanks for the story. I enjoyed the early years, your experiences and experiments with the RS1100RS, and the current state of your battle against the dreaded Bing.

My R1100RS is an early '94 and is a "beta" bike. It too had its transmission replaced under warranty early on. Part of the replacement program was a new final drive, but I kept the old one on because of the lower gear ratio.

Starting has never been a problem with my bike...a couple of cranks and it's running.

However, the Bing bodies have been troublesome. Syncing them needs to be done often. Fortunately it's not difficult especially with a TwinMax tool. Not so fortunate is how quickly the throttle bodies wear at the butterfly valve shafts. I replaced both throttle bodies at 50K, separate parts weren't available at the time...or at least I couldn't locate them back then.

With new, actually slightly used, throttle bodies with non-leaking shafts on the RS it runs great. I'm sure some day I'll hear the dread tap-tap of a butterfly valve caused by a leaky shaft, but 'til then I'm a happy camper.

Karl


On Mar 7, 2010, at 1:53 PM, Dancoe, John wrote:

> Ladies (if any) and Gentlemen:
>  The following is an EXTREMELY long post.
>  It is, as it turns out, nothing less than a memoir of my career as a motorcyclist. The reasons explaining what I’ve done span decades, and the project and the writing of this report itself have literally taken years. Nevertheless, I think this kind of story is exactly what this list is all about.
>  So either hit Delete now, or go start a pot of coffee.
> 
> /*****/
> 
>  Welcome back.
>  The following statement applies to all but the final chapters of this saga: "Long-time Oilheads list members may recall my repeated diatribes on this subject...
> 
> /*****/
> 
>  Until now, this story has existed only as entries in my maintenance log, sporadic e-mail exchanges with various parties, Oilheads list postings, and periodic drunken rants. So for the benefit of new list members and in the interest of continuity now that the story is (in a sense) complete, I’ll start from the beginning.
> 
> /***** 1961 *****/
>  I was born. Did you think I was kidding?
> 
> /***** Huskys *****/
>  I grew up in Lake Orion, Michigan, which is about an hour north of Detroit.
>  My second dirt bike, after learning to ride a Honda SL100 at age 9, was a Swedish-built Husqvarna 125CR. A very hot bike, competitive with the legendary Honda Elsinore.
>  The 125CR came from the factory with an Amal carb. On one of my first rides the slide cap screws vibrated loose, the top came off, the slide popped out, and there I was, a dumb kid sitting on the shoulder of the road with a bike running WFO and no way to throttle back. This was the ride just after Dad and I decided, "No, let's go riding now, we'll install the kill switch when we get back."
>  Not long after this incident, the CR125 got not only a kill switch, but a new carb.
>  Husqvarnas of the time had a long and well-deserved tradition of being hard to start (often requiring a dozen kicks or more), and of fouling spark plugs by the carton. But dad had discovered, first with his 360 Husky, that a Mikuni carb kit would change all that. With a Mikuni those bikes always started on the first or second kick, even in midwinter when I would ride out on the ice and chase my friend around on his snowmobile.
>  The 125 was stolen and with my paper route money I bought a Husqvarna 175WR. Not as good a bike, I think, as the 125. The 175 had a Bing carb instead of an Amal, but it had the same kind of running problems; hard to start, easy to foul.
>  The 175’s problems were also easily solved with a Mikuni. A couple years later when dad bought me my last Husky (a 250CR, also Bing-equipped) for a birthday present, I think he ordered a Lectron carb the same day, and I'm not sure I even bothered to ride the bike until the kit was installed. With the Lectron, my 250CR ran great. My sister's 250WR, and dad's 450WR, both got similar treatment.
>  After I started riding street bikes, my Husky sat without running for about ten years. In 1991 I decided to get it running (good idea) and sell it (bad idea--I should have kept it). I pulled the Lectron intending to overhaul it. But there was literally nothing to overhaul. I blew the dust out of the float bowl, put the carb back on, and the bike started on the second kick.
> 
> /***** The R90S *****/
>  By this time I was riding street bikes, my mom’s Yamaha RD400 and dad’s Yamaha TX750. One day dad came home and said, “You can have the 750”. I went outside and saw why: in the driveway was an immaculate, silver smoke ’75 R90S. I’d never even heard of BMW, but the instant I saw the R90S I never wanted anything else, and that feeling has never really changed.
>  For those not familiar with “airheads”: from 1974-76, BMW built the R90S (900cc pushrod 2-valve boxer), which was the highest-performance bike they'd ever produced up to that point; Reg Pridmore rode it to victory in Daytona against a field of Japanese 4-cylinder machines. I’ll argue it was the finest production bike of its time; there’s no doubt it was world-class and highly desirable. The bike is a real beauty, styled by Hans Muth who later created the first Suzuki Katana.
>  The R90S was the only non-FI bike BMW ever made that didn't came with carbs which weren’t manufactured by Bing Vergasser GMBH. I credit the accelerator-pump-equipped DellOrto slide carbs as a major reason the R90S was such a great bike. Of course the hot cam didn’t hurt, but at any rate I’m fairly sure the R90S remained BMW’s most powerful motorcycle until the K100RS (1000cc FI DOHC liquid-cooled inline 4) came out in '84. If I’m not mistaken the R100RS (1000cc “airhead”) engine, equipped with Bing constant-velocity (CV) carbs, didn't put out as much power as the R90S.
>  And those DellOrtos were reliable. A friend of mine has an R90S with 140,000 miles on it and he says he’s never had to touch the carbs.
>  We moved from Michigan to Phoenix, Arizona in 1978 and during Christmas break that year I rode the R90S to visit my friend (the same friend I used to chase on his snowmobile) who had moved to California. R90S ergonomics fit me perfectly and the bike was just a dream whether blasting across the desert, swooping down the coast highway, or weaving through the mountains east of San Diego.
>  Upon my return I learned of dad’s plans to sell the R90S. I implored him not to...I told him he’d regret it...he did. Several years and 3 owners later, Dad bought the same bike again; unfortunately, it was worse for the wear.
>  After selling the R90S Dad bought me a Honda 400F. That was fine for cruising Central Avenue but it didn’t take long to decide I’d really rather ride, not to mention maintain, a BMW. Every time I had to work on the Honda, I’d recall wistfully how the Boxer twin had only half as many of everything to deal with. No chain to lube or adjust. Nice big nuts and bolts made for European-sized fingers.
> 
> /***** Nada 1 *****/
>  My dream materialized in late 1979 in the form of a '74 R60/6 (600cc), very much the "little brother" to the R90S. The R60, which I named “Nada One” after a favorite song (check out Heart’s Dog And Butterfly album), had 14,000 miles on it when I bought it, which was honestly just broken in. Cleaned up it could have passed for new. Until it had about 30k on it, it ran very well indeed and required very little maintenance. After that, whenever it didn’t run right it was either because of the points or the carbs.
>  Unfortunately the R60/6 didn’t come with DellOrtos. It came with 26mm Bings. Those carbs didn’t even have chokes. For a cold-start device they had “ticklers”, which if you’re lucky enough not to know, are little buttons which when depressed hold the floats down so as to intentionally flood the carbs. Gasoline dripping on your boots is one of the standard features of this design.
>  After the Bings had about 30,000 miles on them, I could spend all morning tuning them, then go for one long ride...and they would be out of adjustment by the end of it.
>  Bing carbs notwithstanding, I credit that motorcycle for much of my career success. For one thing, it was the first motorcycle I’d ever owned that I really wanted to work on. Before that I just wanted to ride them, and ideally let my dad fix them when they needed it. But this machine really opened a new door for me. It fostered a love, respect, and understanding of precision machinery, and led both directly and indirectly to my successes as a machinist, toolmaker, and engineer.
>  And it didn’t hurt that Nada 1 was by far the classiest bike tooling around Arizona State University in those days, where if you drove a car you had to get to school by 5:00 AM or park out behind the stadium...but where dedicated motorcycle parking was no more than 50 yards from any building on campus.
> 
> /***** The 26mm DellOrtos *****/
>  In the summer of 1982 I’d ridden the R60/6 from Arizona to Michigan for the second time, and was working as a toolmaker. A co-worker had recently bought a new Moto Morini 500 (Italian V-twin). He’d had it back to the dealer many times because it didn’t run well. He finally gave up, fabbed a manifold out of aluminum, and mounted a single 36mm Mikuni downdraft carb in place of the two 26mm DellOrtos it had come with.
>  The result was, “Runs great. Gets lousy mileage.”
>  I said, “I’ll take those DellOrtos off your hands.”
>  Excerpts from Nada 1’s Maintenance Log tell the story well. Note: the bike had been completely disassembled the previous December, in order to replace a broken shift detent spring in the transmission. I decided to paint the frame while I was at it; so getting it running again involved somewhat more than just bolting on carbs.
> 
> ----- Nada 1 Maintenance Log -----
> 1983.03.12 @ 67,257 miles
>  She STARTS! Runs rough, but remarkably well for the carbs never having been adjusted. YES!
> 1983.03.15
>  1st RIDE! A BLAST!
>  Runs rough as hell—but still as good as if not better than Bings, even with poor adjustment (impatient to ride…)
> 1983.04.04 @ 67,724 miles
>  Notes—gas mileage 41!
>  Haven’t seen that in a long time.
>  Carbs are somewhat cold-blooded. The choke cable setup of Leon’s must be replaced. Carbs seem to hold adjustment adequately. Idles nicely when warm.
>  Acceleration is good up to indicated 70, probably better than Bings ever were. Above that speed, seems OK, but not terribly enthusiastic. Might be a bit lean up there—I need to do some plug checking before I push her too hard.
>  On the whole, I am quite pleased.
> ----- End log excerpt -----
> 
>  The R60, although its stock carbs had no chokes, had the same airbox housing as the R90S, which featured a mounting boss for a choke lever. I bought the R90S choke lever and cables, and they fit the carbs perfectly.
> 
> ----- Nada 1 Maintenance Log -----
> 1983.04.19 @ 68,131 miles
>  Have installed choke lever—I was right, it was a must. Old setup was really fouling things up. Carbs work much better now, I think I will actually be able to tune them now.
> ----- End log excerpt -----
> 
>  I never did anything with the jetting besides play with the needle position, and I quit doing that after the first few rides. It did take me a while to get the cable adjusters properly sorted out, and I ended up having to make a set myself.
> 
> ----- Nada 1 Maintenance log -----
> 1984.05.28 @ 88,620 miles
>  Wow!
>  Machined throttle cable adjuster screws out of M6-1.00 x 30mm allen head bolts. Tapped top of carbs—the existing hole was larger than the tap drill size, so the thread is pretty loose, but they work! Now I can adjust carbs and they stay synched, at any rate I am now getting almost 46 mpg, at least a 5 mpg gain. Dig it! My DellOrto conversion is fully justified—w/88k bike runs like new and gets better mileage than ever, plus retains synch!
> ----- End log excerpt -----
> 
> /***** Nada 2 and the Bing Constant Atrocities *****/
>  In 1985 I married Laurel Pike, who I’d met in Oxford (near Lake Orion) and who had ridden with me on Nada 1 back to Arizona in 1983. I’d been hoping to find work as a machinist in Flagstaff or Prescott (northern Arizona, higher in elevation thus much cooler than Phoenix).
>  But there are no jobs in Flagstaff or Prescott, so I ended up in the Valley of the Sun again.
>  Immediately when Nada 1 turned over 100,000 miles I began looking for a newer, larger machine. I nearly bought Gary Jorgensen’s ‘77 R100RS (and should have, even though it had well over 100k miles on it). Instead Nada 2 turned out to be a ‘79 R80/7. This bike had the notorious Bing 32mm "flat-top" Constant Velocity (or as I referred to them, Constant Atrocity) carbs.
>  Even people who like Bing carbs think that model was junk. I bought the bike with 25k miles on it, and it gave me a fair amount of trouble (of all kinds, not just carbs--though carbs and carb diaphragms in particular were a major PITA) for the next 50k miles. Ironically, when I sold it with 70k miles on it, I'd sorted it all out and it was running and handling better than it ever had (and had a fresh custom paint job to boot). I’d replaced the flat tops with Bing “dome top” CV carbs salvaged from a friend’s crashed R90/6. I’d actually bought a pair of Mikunis from the junkyard years earlier, but never got around to installing them.
>  By 1991 Laurel and I had had enough of living in the desert. With our 6 month old son John R. we prepared to move back to Michigan. I sold the R80/7, and the Husky 250CR, to finance the move. I brought Nada 1 out of mothballs and rode her for a couple seasons while we got established in Michigan.
>  I test rode a used K100RS. It ran beautifully; I found it boring. I realized I just really like twins. I would have bought, then and there, the Euro-spec R100RS which was also on the lot. However the R100RS was already sold.
>  I kept riding the R60/6.
> 
> /***** Nada 3 *****/
>  By 1993 Nada 1’s alternator was toast; I had a 70 mile range as long as I didn’t use the headlight. I didn’t want to invest in parts for the R60, though; I really wanted a new bike.
>  Then I got a raise just big enough to cover a bike payment.
>  And BMW introduced the R1100RS, the first ground-up redesign of the Boxer since the R90S. The new engine was immediately nicknamed the “oilhead” because of the oil cooling circuit built into the cylinder head.
>  It took me most of 1993 to make up my mind; I spent months then weeks then hours then minutes vacillating.
>  “I could get a R100RS for $4,000”, I said to myself, “Compared to $13,000 for an R1100RS.”
>  “But the R1100RS has, like, 40% more power”, I argued back.
>  “The airhead design is totally mature and bulletproof; I’d know exactly what I was getting. By contrast, the oilhead is an essentially unproven design.”
>  “But the R1100RS has radial tires and ABS.”
>  “I have years of experience and special tools for servicing airheads; yet BMW would prefer me to think I won’t even be able to work on an R1100.”
>  “But the R1100RS doesn't have Bing carbs.”
>  “And furthermore...wait a minute, you’ve got me there.”
>  Seriously, three things most people wouldn’t even think about are what tipped my balance in favor of the R1100RS:
> 
>  1) I’d long grown weary of pouring oil down the side of airhead engines instead of into the filler hole, which is hidden behind the carburetor cables and almost impossible to get to without a foot-long funnel. If I bought an airhead I’d have to immediately drill an oil filler hole in the rocker cover and come up with a decent cap plug for it.
> 
>  2) I was also tired of burning my fingers getting the damn dipstick out of those damn airhead filler holes. So if I bought an airhead, I’d have to engineer some kind of oil sight glass so I’d never have to unscrew a dipstick again.
> 
>  3) If I bought an airhead, I’d have to immediately buy and install a set of aftermarket carbs to replace the Bings.
> 
>  Knowing (or thinking I knew) the R11RS "solved" those three issues were a major part of the reason I ultimately chose it. The night-and-day difference in performance was the biggest reason, of course. ABS and modern radial tires were additional justifications on grounds of safety. But in any case, once I decided on the oilhead I never regretted it. To my delight I find the oilhead every bit as shade-tree wrenchable as an airhead. I much prefer it in fact. Overall, for my purposes, R1100RS is the best bike I've ever ridden BAR NONE.
>  Note: I admit not riding hot Italian and Japanese sport bikes precisely because I’m afraid I might like them. When I bought my R11RS I vowed to ride it 10 years and 100,000 miles, and I haven’t done the miles yet; I’ve still got 4,000 to go.
> 
> /***** Nada 3: the early years *****/
>  So finally we’re getting to what this story is all about.
>  Almost.
>  BMW R1100RS “Nada 3” was built in May 1993, meaning she is one of the very first production units, a.k.a., one of the infamous “Beta Bikes”. And yes, like many others I had clutch and transmission problems. But check this out:
> 
> ----- Nada 3 Maintenance Log -----
> 1994.03.21 @ 1,216 miles
>  Dropped off at BMWDet [for break-in maintenance], mentioned to Don that bike had never been easy to start.  He said, "Everyone says that about these bikes", Jim said it's typical of new motors.
> 1994.03.23
>  Picked up bike. See checklist & stamp in book. RO#1374. Noted valve noise as noticeably louder on one side than other. Figured I can do at least that well.
> ----- End log excerpt -----
> 
> ----- Fax to Jim Musgrave at BMW of Detroit -----
> 1994.04.05
>  My R11 fuel system needs adjustment.
>  Description:
>  1. Usually idle (warm) 1000 RPM +/- needle width. Occasionally stalls at intersections, however, even warm; problem is getting progressively worse.
>  2. When I took delivery I would have described the transition from idle as “abrupt"; these days I would say “there is a big flat spot off idle.”
>  3. Has always been reluctant to cold start, even at 50+ deg. ambient. I mentioned item 3 to Don when before the break-in service, he said "everybody says that"; you said it was a symptom of a new engine. If what you say is the case, fine, but I will not accept this situation forever. CW [note: was actually Motorcyclist] did a comparo between new/old boxers and noted how easy the R11 lit off, so it must be possible to achieve (they also mentioned the R100 didn't, which means it was out of tune because my boxers have always started on the first crank when tuned properly). The fuel system box on the service list was not checked off, so I assume nothing was done. I'll call to schedule a look at this. She's not unrideable (yet), so it's not urgent.
> ----- End fax transcript -----
> 
> ----- Nada 3 Maintenance Log -----
> 1994.06.02 @ 4,600
>  BMWDet checked fuel system, slight leakage at flanges. Out of synch. Don said after adjustments “runs as well as any.” I note: still hard to start. Still flat off idle when cold if no choke. Flat spot goes away when warm. Hasn't stalled at intersection since.
> ----- End log excerpt -----
> 
>  So...even from the start I was disillusioned with the cold starting of the bike. I also found myself thinking, “As often as I’ve got to fiddle with these throttle bodies, to keep it idling right and synched and to prevent surging, these might as well be Bing carbs.”
>  Honestly, that thought went through my mind many times.
>  So how do you think I felt a year or so later when, while peering up at the bottom of a throttle body, I noted the name BING cast into it?
>  “Well no !^$*ing wonder”, I thought.
>  And ever since then I’ve been irate that BMW put that one over on me.
>  But I have to say again that my R11RS, and I mean the one specific example of R1100RS production that is sitting in my garage, is the best bike I’ve ever ridden. When it was built, it had been targeted at, and hit dead on, an extraordinarily small demographic in which I was pretty much dead-center; I’ve often said quite sincerely the bike was built specifically for me.
>  And the first 50-60,000 miles were a lot of fantastic rides (one was the absolute worst ride of my life EVER ANYWHERE, but that was no fault of the bike).
>  In 1993, there was no better bike in the world for me, I’m certain of that. What’s more, I think it’s entirely possible that I could, today, go out and test ride every other bike in the world, and still conclude that Nada 3 suits me best.
>  I’m a very lucky guy.
> 
> /***** Nada 3: a successful modification *****/
>  At 55,643 miles, I removed the ABS system and installed braided stainless steel lines on the front brake. To this day, it is absolutely the second-best best thing I’ve ever done to the bike. Brake performance went from mushy and (at times terrifyingly) unpredictable to firm, progressive, and absolutely reliable. I remain utterly thrilled with the result and 40,000 miles later notice and appreciate it literally every time I ride.
>  It was exactly what I had hoped to achieve.
>  No more, no less.
>  My success in this project gave me confidence in how well I know my own preferences and also at my ability to second-guess the BMW engineers.
>  Why was removing ABS only the second-best thing I’ve done to the bike?
>  The first best thing was my discovery of a grade of black shoe polish which is effective in covering the stock seat’s original hideous teal color.
> 
> /***** Yet another Bing FAIL *****/
> By 2002, things were not so rosy.
> 
> ----- Monthly Riding Log -----
> 2002.11 @ 67,956
>  LH head gasket, tires badly in need of replacement
> 2003.06 @ 68,000
>  Out of town a lot, didn't ride
> 2003.09 @ 70,119
>  LH head gasket seeping severely
> ----- End log excerpt -----
> 
> ----- Nada 3 Maintenance Log -----
> 2003.12.18 @ 70,917
>  RPL LH head gasket.
> 2004.04.02 @ 71,350
>  Gasket seepage stopped.
>  No noticeable performance change.
>  Running like shit; backfiring, belching, stalling at intersections, hard to start
>  Has been getting worse over time
>  Suspect Bings
>  Disinclined to work on it
> 2004.08.30 @ 72,770
>  Running worse and worse
>  Bike is almost unrideable.
>  Tried a variety of spark plugs—no effect.
>  ...
>  Determined RH throttle shaft worn. With air tube off can see the plate flopping around in the bore. If I put my finger on it and hold it down, smooths out.
>  $*%()^ Bings
> ----- End log excerpt -----
> 
>  My log entries appear to indicate I originally suspected the head gasket, which eventually reached the “stained garage floor” stage. But I assure you, from the moment I noted the deteriorating performance, I really suspected the Bings. In fact, I do not consider it completely implausible that the depths of my loathing for Bing fuel control devices may have telekinetically accelerated wear of the throttle bodies.
>  I tried many standard diagnostic tests (just all the wrong ones). As I wrote in correspondence at the time:
> 
> ----- 2004 e-mail -----
> My bike has been more trouble free than many I've read about [on the Oilheads mailgroup], but I did end up with a shot clutch and worn input splines at 50k, replaced one head gasket at 30k and the other at 70k (thinking that was my poor running problem, but replacing it made no difference). I also have the external fuel filter mod (and the filter is new, that isn't my problem either).
> I have already done (2) careful valve adjustments (the first just after the head gasket replacement, the next one very recently). No effect. I am a former toolmaker and consider myself very good at valve adjustments, which I've done on boxers over the course of 220k miles since '79. I like the RS because the adjustment is extremely stable. It's unusual to have to correct one, even at 12,000 mile intervals (I quit doing adjustments every 6k years ago).
> I've done compression checks. My readings, probably due to poor operator technic, bounced around enough that it was hard to say exactly what "the" reading was, or whether both cylinders were within 10% of each other; but both were definitely making compression up to 60-70% of gage scale. However I can't rule this out as a possible problem.
> I've used 3 bottles of injector solvent and then checked the injectors. They are making good conical spray patterns on both sides, and increase output volume with RPM. I've done the Lentini zero-zero technic.
> I've blown out the orifices out in the throttle bodies with compressed air after dosing them with carb cleaner, but there are definitely some ugly symptoms in the throttle bodies. A lot of black crud accumulates on the idle bypass screws and the throttle body bores are sooty (I've been getting a lot of belching, backfiring, and surging). I can take the bypass screws out completely and make almost no difference in idle speed, but there is definitely some air flow thru the orifices with the screws out. I did get a serious case of diesel fuel contamination a few years back, which may be a factor here.
> ----- End e-mail excerpt -----
> 
> /***** An Inspiration *****/
>  Through the winter of 2004-2005 I chased down a replacement throttle shaft, suspecting that it would not, ultimately, restore original performance, as I wrote to the Oilheads list:
> 
> ----- 2005.02.02 Oilheads post-----
> Tom Cutter wrote:
> 
>> Rumor is that the Euro go-fast boys are fitting Mikuni smoothbores, 41mm, to their R1100S's and getting around 108 hp at the rear wheel.
> [John responded:]
> I...JUST...KNEW...IT!!!!!!!!!!!
> 
> Those who've been on this list for very long will have endured my many Bing diatribes and may recall my periodic threats to do exactly as these "Euro go-fast boys" are purportedly doing.
> 
> In fact the oilhead might not have even been out of its first production year when (I think it was MOA Owners News) featured a cover pic of a race-prepped RS equipped with DellOrtos (and White Power forks sans Telelever, which I found puzzling. I've never done anything but rave for the Telelever--the best feature of the bike).
> 
> My R11RS has always been the worst-starting street bike I've ever had and, in fact, at this very moment is completely inop precisely because of the ^&^%$$^%& Bing throttle body for which I have finally, after weeks of waiting, received a replacement butterfly shaft and screws.
> 
> I have no expectation that replacing these components will restore the bike to its original performance, but I'm hoping it will at least be rideable and with even more luck, enjoyable, again.
> 
> Is a Mikuni **KIT** available????? I would absolutely be interested.
> ----- End post -----
> 
> I was right about the shaft not curing all ills:
> 
> ----- Nada 3 Maintenance Log -----
> 2005.02.04 @ 73,208
> RPL RH throttle shaft.
> Shaft bore looked nasty, nothing can be done about it.
> Result: Runs significantly better but still infuriatingly poor.
> Assume both $*%()^ Bings are shot
> ----- End log excerpt -----
> 
> I did not want to buy anything else with the name BING on it, but I didn’t know whether a carb conversion would work. I had no luck getting in contact with anyone who’d done it. But I was formulating some theories and possible plans of action, which I’d shared to the Oilheads list:
> 
> ----- 2005.02.05 Oilheads post -----
>> From: "Tom Brown" <tbrown@xxxxxxxxxxx>
>> Subject: Carbs etc.
>> 
>> John:
>> I think you're entering a whole new world trying to put carbs on an oilhead.
> 
> No doubt! But I keep stressing, I don't want to be a pioneer. I think people have done this before and might very well have developed excellent solutions. I just don't know their e-mail addresses.
> 
>> Be prepared to replace the motronic completely with analog ignition etc.
>> All the fuel curves etc are going to be completely wrong.
> 
> I'm not at all sure about that (but I don't know what I don't know). I DO know the "fuel curve" would be a non-issue. The fuel pump will simply go away, which will a) make the bike a few grams lighter, b) give me a few cc's more fuel capacity, c) be one less thing to leave me stranded on the roadside, and d) greatly reduce the probability of my externally-mounted fuel filter exploding. All Good Things.
> 
> Fuel would be supplied to float bowls via gravity feed. "Fuel curves" would be provided by the carburetor jets and the needle (that's what they're for). If the Motronic was still energized and felt it needed to send more or less fuel thru the injectors, based on whatever information it was collecting at any given millisecond, it really wouldn't matter since there would be no injectors.
> 
> The real issue would be the IGNITION curve. I have no idea if that would be right. But let's think about it:
> 
> Replacement of the carbs would result in the disconnection of the Throttle Position Sensor (TPS) and injectors. The airbox sensor and O2 sensor would remain.
> 
> My assumption is that even with TPS and injector connectors dead-ended the Motronic would still generate a spark at some point during each crank revolution (every other one, in a given cylinder, being the usual "waste spark"). That seems like basic limp-home functionality which I assume Motronic provides. Would it advance properly? Perhaps not. But is there any kind of vacuum sensor feeding information to Motronic? Not to my knowledge. Does Motronic use TPS data to alter ignition timing? Possibly. Does it use information from the airbox and/or O2 sensors to make ignition timing adjustments? Possibly. Does Motronic make advance adjustments based on RPM? I assume it must.
> 
> Is ignition advance based ENTIRELY on RPM? I dunno; seems simplistic so I doubt it. But perhaps all those sensors exist simply to provide data for the FUEL curve...which again, I no longer care about. Maybe ignition timing is based entirely on RPM + O2 + airbox sensor value, wouldn't that be nice? In that case as long as the carbs made the engine speed go up and down when I wanted it to, and the mixture was close, the Motronic would provide a spark exactly when it should. In fact, unless the ignition curve is weighted HEAVILY to TPS value, it seems plausible to me that it might continue to work properly or at least acceptably.
> 
> But I may be dead wrong. This (aside from exact jetting specs) is the single biggest mystery (to me) about the concept.
> 
> But again, I assume that for some, these mysteries have already been solved.
> 
>> As far as your fear that the throttle bodies need to be adjusted all the time,
>> well, that's just not true.  You need to adjust when you adjust valves
>> because changing the valve clearance affects the vacuum in the throttle bodies
>> just as it would in carbs.
> 
> I disagree. One of the most delightful things about the oilhead engine is how well it maintains valve adjustment compared to an airhead. While the bike was still on warrantee, I used to check my valve adjustment every 6k miles. But I found I rarely had to touch them, even when the engine was new and I fully expected some "settle in". Since the warrantee is up I only check them every 12k miles and still rarely need to fiddle.
> 
> I DO know how to adjust the valves. When I brought the bike home from the break-in maintenance, I noted that if I leaned to the right, the sound of the valves was different than if I leaned to the left. "I don't know if either side is actually OUT of spec", I thought to myself, "but I DO know that I can at least get them the same." And I did just that. I adjusted the valves myself the next time and it was by far the most adjustment they have ever required, and yes when I was done they "sounded" the same no matter which way I leaned as I was riding.
> 
> At 73k miles with no valve problems, and with "surging" having been at times noticeable but by no means as severe as many others on this list have reported, one can assume I'm "good enough" at adjusting oilhead valves.
> 
> Now, having said all that, let me add that many times the bike would begin to surge, and/or would lose fuel economy, and/or would run rough, whatever. By fiddling with the damned Bings (and ignoring the valve adjustment which a few thousand miles later would prove fine) I was able to get it running right again. That was when the Bings were still new, of course.
> 
> Let me also mention (again) that this is the WORST STARTING STREET BIKE I HAVE EVER HAD, AND HAS BEEN SINCE DAY 1. Fuel injected motors are supposed to be "don't touch the throttle, just punch the start button". But it is common, probably universal, among oilhead owners to have developed some kind of throttle gyration just to get the bike started.
> 
> My particular method is throttle wide open CRANKCRANKCRANKCRANKCRANKCRANK snap throttle shut.
> 
> What's yours?
> 
> I have to crank the starter of this bike 3x-5x more than any airhead I ever had. My airheads, when properly tuned (even with Bing carbs) would start on the first ignition stroke; you'd never even hear the starter motor. This is an aspect of my oilhead that has always pissed me off. My theory (and it is only that) is that the Motronic deliberately delays starting. You crank it a few times until the Motronic figures out what the conditions are, decides what to do, and then grudgingly provides a spark and/or fuel. Note I'm not blaming the Bings for this particular characteristic (though it wouldn't surprise me at all to find they are at fault).
> 
>> When you synch, all you're really doing is adjusting the length of one
>> throttle cable so the vacuums match on both sides.
>> This doesn't take long and isn't needed that often.
> 
> Yes, I understand. However our definitions of "too long" and "that often" are not the same. I feel that the right side thottle being a slave to the left is inherently problematic. And I regard the adjusters as an ergonomic PITA.
> 
>> [snip] These bikes are very smooth by comparison.
>> The bit of vibration you do feel can be eliminated by careful tweaking,
>> but it's not likely to be any different with different carburation.
> 
> I agree these bikes are remarkably smooth for big bore twins (near-perfect primary balance being the reason). The fact that it isn't as smooth as a K-bike is in fact one reason I like it.
> 
> Note however I've deliberatly avoided riding things like Ducatis and high-performance UJMs, which might tarnish my satisfaction.
> 
> But I'm not talking about "a bit of vibration" here. I'm talking about lousy starting, frequent need for adjustment, not particularly good mileage, poor durability. By the end of last season my bike was unrideable. I admit I was dumb to not diagnose the root cause far sooner (I was pissed that I had to deal with such a problem at all, and was disinclined to put time into it); but my original suspicion that it was a Bing problem certainly proved correct.
> 
> And you have to understand my perspective here: all of the problems I've just listed are ABSOLUTELY TYPICAL of my experience with Bing fuel mixers. And I HAVE NEVER, NOT ONCE, NOT EVER, FOUND REPLACEMENT OF A BING FUEL MIXING DEVICE TO BE ANYTHING BUT A SUBSTANTIAL IMPROVEMENT TO MY MOTORCYCLE.
> 
> Can I emphasize that again? EVERY TIME I'VE DONE IT I'VE BEEN THRILLED WITH THE RESULT.
> 
> EVERY TIME.
> 
> EVERY SINGLE TIME.
> 
> Whether replacing the throttle bodies on my R11 is a good idea or not is certainly an open question, but my experience with Bings to date--INCLUDING the ones on my R11--is not.
> 
>> If you're just looking for more power, like for racing, this may be a good way
>> to go.  In racing, you're not concerned so much with low end torque,
>> smoothness at lower speeds, the ability to idle smoothly without stalling or
>> hunting etc.   Many of the fastest race bikes run like absolute crap at sane
>> speeds.    It's not a priority.
> 
> You are absolutely right. It is entirely likely that whatever these "Euro go-fast boys" have come up with would not idle, would get lousy mileage, would be rough at anything less than 5k RPM, and would have none of the good manners which this bike, when new, had in spades.
> 
> But it's also entirely possible (and I think likely) that this purported 108 HP recipe, when dialed down a bit, might yield exactly what I'm looking for. I'm not dying for more power, I'd be happy just to get my original performance back. But I sure wouldn't mind another 10 HP, if it didn't come at the price of reliability and ridability.
> 
>> If this is your main street bike, my advice is to stick with the stock stuff
>> and maximize your enjoyment of it by eliminating the surge problem and keeping
>> it synched and tuned.    If it's more of a toy or science project for you,
>> well, go for it.   Who cares if it won't run?
> 
> No, my bike isn't a toy or a project. It's my ride to work in the summer and used to be how I spent my vacations (I hope it will be again). It's very important that it runs well in the real world. But keep in mind, it could not possibly run worse than it did last season. At one point I seriously considered taking the 26mm DellOrtos from my R60, wrapping the intake bosses with duct tape until they were big enough to clamp into the R11, and simply seeing if it would idle. If so, it would have been a 500% improvement.
> 
>> To equate the motronic/throttle body system with Bing carburators of old is
>> not valid.   There is a bearing, especially on the right side throttle body
>> that can go out and cause the bikes not to synch well and make a little
>> rattling noise on the right side.    This can happen on high mileage bikes.
> 
> Bearing, schmearing. There's always a reason, usually several, that Bings don't work well. Frankly, with carb/carb swaps it was simply that other makes were  designed and/or built better. Nobody would make the argument that a Yugo is built better than a Honda, and I think you'd be wrong to argue Bings are built better than Mikunis. True, arguing Bing THROTTLE BODY < Mikuni CARB is a bit like arguing Apples < Oranges. It's probably even more like arguing Horse Apples < Oranges.
> 
>> Just replace the throttle body or the bearing if you can find one
>> and be done with it.
> 
> Well, that's what I've just done; it was finally warm enough yesterday to work out in the garage. Actually I replaced just the right-hand shaft. When I got it apart the bushings didn't look all that great but it went back together that way anyhow. The rattling has gone away for now but I expect it to be back, probably with rattling on the left side to match. But at least I got the bike to idle (though not all that well). Hoorah.
> 
> It was cheap and expedient and far easier than installing a perfectly-engineered Mikuni kit would have been even if such a thing existed. But I do not expect long-term satisfaction, and until I do the 0=0 schtick I still won't know for sure where I'm at.
> ...which is what I should have done today instead of all this exposition...!
> 
>> These are great bikes...
> 
> I agree completely. There's no question it was the best possible bike FOR ME from the day I bought it until the turn of the century, and there's every possibility, with a bit of tuning up, that it will continue to serve me well into this one.
> I argued that when it came out it the R1100RS was best production motorcycle ever built, and I believe that.
> And I do want to love it again.
> 
>> ...the way they are.
> 
> Again, we differ. As I mentioned earlier, I find the oilhead to be eminently shade-treeable and by tweaking it I have made what are for me, substantial improvements. My favorite example is my decision to remove the ABS. This is a subject all its own which has already been beat to death. The point I want to make from it is that once I had done it, the results did not exceed my expectations.
> 
> They MET my expectations.
> 
> EXACTLY.
> 
> I got PRECISELY the results I expected and desired. This is an example of how well I know the bike, and how well I know my own preferences.
> 
> Had I decided to leave it "the way it was" I would have denied myself the single biggest improvement I have made to the bike.
> 
>> Learn to get the most out of them and you'll be pretty thrilled.
> 
> I spent several years and tens of thousands of miles being totally thrilled. Then I spent a few years and a few thousand more miles being blase. And then a couple years becoming progressively more pissed-off (thank you, BING).
> 
> I hope that yesterday's repair and tomorrow's tuning will again make this a thrilling bike. It's possible.
> 
> But I have, MANY times in the past, been thrilled by the difference between a motorcycle with Bing and that same motorcycle with Mikuni|Lectron|DellOrto.
> 
> That is ALSO possible.
> 
> John D
> ----- End post 2005.02.05 -----
> 
> /***** A dream becomes reality *****/
>  One Saturday morning in May 2005 I had very pleasant dream:
>     I've done the DellOrto installation and started the bike. Somehow I have
>     throttle control rigged up. The bike runs quite nicely for a little while.
>     Then it dies suddenly. I find the R11 has morphed into the R60, which
>     naturally quit running--quite understandable, since it lacks a battery.
>  (I always write my dream diary in present tense).
>  This dream inspired me to do the experiment.
>  The next day I pulled the carbs, the entire twistgrip assembly, the choke lever, and cables from the R60. I then did an extremely poor maintenance on the carbs. They definitely need new O-rings; but I didn't have any, so they went back together anyway. One float bowl was pretty clean, but the other was filled with black sludge. I cleaned that out and attempted to clean all the jets which I could remove easily; but some jets were so clogged I couldn't get them open, and some wouldn't loosen so I left them as-is rather than risk breaking them.
>  I wrapped the intake spigots with DUCT TAPE until they were big enough to clamp into the R11 manifolds, and rigged the tank's return (i.e. non-pressurized) hose as a supply to the carbs. I hooked up the cables and controls, draping them haphazardly over the semi-exposed midriff of the bike in a satisfyingly Frankensteinian manner.
>  I pushed the start button.
>  It wanted to start on the first crank, much more enthusiastically than it EVER did with the fuel injection, even when it was new. I fiddled with the choke and throttle a bit.  After a few tries, including one backfire that blew the right hand carb off, the thing started, settled down, and ran surprisingly well. It actually idled.
>  Once again, keep in mind: these carbs had not run the R60 motor for over ten years; they'd been sitting with oily rags stuffed inside them. Many of the O-rings were totally shot or missing, all needed replacement, and at least one jet in each carb was completely blocked. The float bowl on one leaked continuously. The idle fuel adjuster screw on one had been replaced with a set screw. The carbs were far too small for the 1100cc motor. I did not make the slightest attempt to adjust a mixture screw or a cable; the cables were in such bad shape it probably would have been pointless, had I even cared enough to try.
>  Despite all this, it ran almost as well as it did the last time I had the UGWPOFSBings on it!
>  Next: the real point of the test. I put the timing light on, revved it up and down a few times, and confirmed that yes, Virginia, there is ignition advance with no throttle position sensor input. My calibrated eyeball determined the advance was "about" right; I was guessing/hoping it was at least as good a curve as that which a centrifugal advance would provide.
>  Then it backfired again and blew the left hand carb off.
>  But no matter, the experiment was complete.
>  The R11 Carb Project was GO!
>  I decided from the outset to install Lectron carbs. This was because I knew from my exerience with Husqvarna that Lectrons were a simple and dependable design without a ridiculous variety of jets and adjustments. I thought Mikuni or DellOrto would be  execellent choices also, but that getting close on the jetting might be a very lengthy process with either of them.
>  I tracked down a Lectron distributor, Fast By Gast in Buffalo NY. I explained to Kevin what I was doing and sent him a sketch of the throttle bodies. He immediately recommended 44mm Lectrons. 44mm was just about the same bore as the thottle bodies and would fit the airbox tubes and manifolds well, but I told him if he thought 42, 40 or even 38mm was a better choice that I would believe him; I knew that too large a venturi would reduce intake velocity and increase fuel consumption. But he assured me it was the right size and that he could provide a range of power jets and a metering rod that would put me in the ballpark.
>  I defined four criteria against which I would evaluate the success of the project:
> 
>  1. It had to start.
>  2. It had to idle.
>  3. Performance had to be comparable or superior to stock.
>  4. Fuel economy should preferably be not outrageously worse than stock.
> 
>  It took me a bit of phone tag to make sure I wasn't going to get something unexpected, or fail to get something important. I ordered a set of carbs, new intake manifolds, and some control cables Kevin thought might be useful though they were for a different application.
>  The cables and manifolds arrived in a couple of days. The manifolds fit perfectly and the cables, though intended for use with a 4 cylinder motor, looked as if they would yield some useful parts. The carbs took longer to arrive; they had to be special ordered as a set with 1 left-hand, 1 right-hand (that is, the adjustment screws need to face out from the motor on each side).
> 
>  I burned a lot of midnight oil getting them rigged up. The trickiest part by far was the cables. The assemblies Kevin had supplied, which took a single cable from the handlebar and split into four cables going to the carbs, were both throttle cables; but I intended to use one of them for the choke control, which has a totally different travel. Furthermore, while the upper ends of the cables were totally usable, the lower parts were far too short.
>  It was enjoyable work though. I got to bring out my machinist gages and tools and dust off my mechanical design skills for the first time in far too long.
>  Long story short: I cannibalized the original throttle and choke wires from my bike, put those into the upper sheaths I got from Kevin, bought a few more sheaths and cables from the local bicycle shop, and with a couple more pieces from Ace Hardware cobbled them all together well enough to work.
>  More parts from the plumbing section at Ace (it's a bit disconcerting how many toilet parts are now integral components of my motorcycle) got me the adapters I needed to connect the airbox tubes to the carb intakes. A remarkably clean setup, actually. It would have been even better if I'd had a hot wire instead of a hacksaw and X-Acto knife, but you need to look fairly close to notice that.
> 
> /***** It’s Alive! *****/
>  Sunday night, 2005.06.12 21:05.
>  I finally hit the starter button.
>  Wouldn't start.
>  Didn't even want to.
>  Hmm.
>  One nice thing about Lectron carbs is the transparent float bowl. Guess what...no gas in them. I removed the filter and the float bowls filled right up.
>  21:10.
>  I admit it took two tries...then she fired right up and settled to a smooth idle. I killed and restarted a few times. It didn't take long to get the hang of it; no choke, open the throttle just a crack...and it started far, far more eagerly than it ever did with the UGWPOFSBings.
> 
>  Criteria #1: satisfied!
>  Criteria #2: satisfied!
> 
>  I put the body panels back on, and then it was out for a test ride.
> 
>  Criteria #3: Satisfied!
> 
>  The bike performed very much like the bike I bought in 1993, and far better than it had in years. Transition from idle was excellent, perhaps better than ever. Transition was much better than on Laurel's Yamaha Seca II which I'd been riding since I’d given up riding the BMW months before.
>  My best 0-60 time was 4.33. Keep in mind that was me eyeballing an LCD wrist chronometer duct-taped to the triple clamp. Me, not a professional rider on somebody else’s professionally-tuned bike with instructions to obtain the best possible time regardless of what the clutch smelled like afterward.
>  For sure, the bike had far more power than it had clutch.
>  But I had to admit, it ran rough and totally ran out of steam at higher RPM. I assumed the latter was because my crudely-built cables didn’t raise the slides more than 75% open. I’d already started thinking about cable design v2, and hadn’t even started to play with the jet selection Kevin had provided, or with the metering rods, or even synchronize left vs. right. The cable assemblies were so rough that it wasn’t worth a serious tuning effort.
>  But even so, the bike was entirely enjoyable, and only slightly less so than when new.
>  My old friend was back!!!
>  I’d fully expected to suffer in the fuel economy department. I was just hoping not to suffer too much. My first tankful, which was a mix of backroads but mostly 80 mph freeway cruising, yielded 29.7 mpg. That was quite a bit worse than I was expecting. However, a plug check indicated a predictably over-rich and presumably correctable mixture.
>  Over the next couple weeks I continued to fiddle with the carb adjustments during my daily commuting and, when I had the chance, joyrides which I enjoyed with great relish.
> 
> ----- Correspondence 2005.07.15 -----
>  The BMW's running great. On Saturday July 3 I had all day to ride around and fiddle with the carbs, basically just leaning the metering rod position quite a bit from the original settings. I managed to squeak out 41.7 MPG which is damn near as good as I ever got with FI (I admit that was all freeway at the speed limit; but I had to ride pretty mellow with the FI to get that too).
>  It was absolutely perfect weather so it was really a delightful day. Once I hit my mileage bogie I stopped at the Clarkston Union, enjoyed a couple of excellent beers and had the barkeep switch the TVs from baseball to the Tour de France. The next day Laurel and I went for a very nice ride together for the first time in way too long. That ride included champagne brunch at the Union where the TVs were still tuned to the Tour. I'd had a big success at work that week, so I really had a great 4th of July weekend.
>  Overall the last tankful was in the low 30s, but a lot of that was with richer jetting than it has now (not to mention quite a few acceleration tests!), so I expect the next tank to go further. Still could use a little more dialing in but I could ride it the way it is now forever and not mind. I really love how nicely it starts now...far better than it ever did.
> ----- End correspondence -----
> 
>  Criteria #4: Satisfied!
> 
>  Well, sort of.
> 
>  Although I was able to eke out almost 42 mpg that day in July by riding easy on the freeway, that metering rod position proved too lean for anything like decent performance and I found I needed to richen it back up a tad. At that point, in daily commuting my low fuel light tended to come on at about 160 miles. Which compared rather unfavorably to the 180 mile range the fuel injection used to provide when it was working well.
>  And the top end was still noticeably absent. At anything above 70 mph or so, there just wasn’t much power at all; getting to 100 mph was a pretty lengthy process, and that was IT.
>  I had a decent set of cables made that gave me nearly 100% travel. Getting the last couple millimeters would mean grinding some material off the twistgrip stop, but I could tell that wasn’t the issue. Getting the additional slide travel didn’t do anything for the problem.
>  But at the time, I was still happy. The bike was running better than it had for years, in fact it ran great off the line, and pretty well up to any legal speed. Good enough for the commuting that was 99% of my riding at the time.
>  And I had the satisfaction of having, as far as I was concerned, proven my point. My bets and guesses had, for the most part, paid off. The bike wasn’t perfect, but I could live with it, and did for the next few years.
> 
> /***** Flash forward: 2009 *****/
>  By late last season, I was about done with the carbs and was considering re-installing the fuel injection. My complaints included:
>  1. I was really getting tired of having no roll-on power.
>  2. For some reason, Lectron doesn’t make cable boots for the cold-start devices. I’d tried to fashion some of my own out of vinyl caps, but they were inadequate. The cold-start plungers were hopelessly water-fouled.
>  3. I’d had repeated problems with fuel starvation. Some may have been due wholly or partially due to fuel line routing inducing a vapor lock, or perhaps clogged or broken fuel tank internal vent lines. But signs indicated problems with the float valves as well.
>  I contacted the Bing Agency and started pricing throttle body replacements. But I really didn’t relish the work it would take to refit them, not to mention the cost.
>  So I also tracked down Kevin, the guy who’d originally set me up with the carbs. He’s now the owner of Lectron Fuel Systems. I described my problems and it turns out, well, I should have got in touch with him years ago.
> 
>  1. Kevin had only sent me one set of rods, years ago, because they’re kind of expensive, and he figured they’d be the right ones for the application. I was pretty confident by now the carbs were just generally way too rich. So Kevin sold me a selection of leaner metering rods and power jets. I’ll be able to return the rods I don’t need.
>  2. The obvious solution to the cold-start cable boot problem is...just use a throttle cable boot. It looks a bit weird, but so what.
>  3. Now available: a spring-loaded float valve, to solve exactly the kind of problem I’ve been having.
> 
> The result:
> 
> ----- Nada 3 Maintenance Log -----
> 2009.10.26 @ 95,222
> New spring-loaded float valves.
> New choke tips, springs.
> New cable boots on throttle AND choke.
> Installed fuel filter.
> 
> Started with #3-1XL rod @2.039:
> Too lean (backfiring); set @2.005
> Initial freeway run:
>  YEAH BABY!! Hesitation above ¾ throttle is gone (or at least, much farther up now). Perhaps slightly less off the line than before, but pulls strong all the way to 100 mph...perhaps at bit less strong near top end, but FAR FAR BETTER than ever before with these carbs. Up to 115 mph, there was some more left, but too much traffic to really push it. ¾ throttle plug reading, almost nice.
> ----- End log excerpt -----
>