Re: CCP,gas mileage and vibration

["Steve Makohin" <wateredg@xxxxxxxxxxxx>]

Hello Peter

From: " Peter J Minkow" <pjminkow@xxxxxxxxxxxxx>
Sent: Thursday, June 10, 2004 11:40 AM

> A number of months ago, I posted a request for info about how to
> increase my low gas mileage (low 30s) on my '95 R1100R with
> catless Remus exhaust. Oxygen sensor is in place. I had
> removed the ccp per suggestions on the list and achieved better
> power and worse gas mileage. I decided to replace the ccp and
> my mileage bounced back up to the low 40s. The problem is that
> I then developed an odd vibration at about 3500 rpms. I decided
> to remove the ccp, once again, to see what effect that had on the
> vibration. The vibration pretty much disappeared. So, do I have
> to choose between high gas mileage and smooth engine
> performance or is there a way to get both?

I have a 2000 R1100S with a catless Vanderlinde exhaust. The bike shipped
without a Cat Code Plug (CCP). It originally developed a mild surge which I
was able to eradicate by turning up the Throttle Position Sensor (TPS) to
~0.37 volts, but at the cost of increased fuel consumption. A recent
experience I had is worth talking about here.

Several weeks ago, I was preparing to upgrade my bike with a dual-plug
upgrade kit from San Jose BMW. My issues at the time were (1) a flat spot in
the low end of the throttle (which I could feel if I slowly rolled on the
throttle under light load at low to mid RPM, say around 2000-3000 RPM), (2)
"excessive" engine vibration, and (3) "sputter" which could be experienced
when cruising under light load at lowish RPM, around 2500-2500. Yeah, I know
they were minor issues, but I love my R1100S, and I'd prefer if the engine
was smoother.

My "dual plugging" discussion happened with the head motorcycle mechanic at
Budds BMW, my local car/bike BMW dealer. The wrench, John Parker of John
Parker Racing fame, is a professional engine tuner by trade -- a significant
differentiator from a "mechanic." John and I talked about the process we
would carry out with him removing my bike's body work, the existing heads,
shipping them to SJ BMW for drilling, and so on, and the costs for doing the
work (over US$1000 including all parts and about 8 hours labor). John then
suggested that I leave the bike with him and let him experiment with it for
a few days before I decide on dual plugging. He suspected that he might be
able to give me most of what I wanted with nothing more than proper tuning,
and with a different set of spark plugs than the stock BMW ones.

I was skeptical, but after riding the slightly altered bike, I was floored
by the difference! There was not a hint of a surge anywhere (as before), but
now, there were no flat spots, no sputtering, no hesitation, no rough edges.
Just clean, predictable throttle response. The engine even felt like it
vibrated noticeably less. On the down side, when the bike is warmed up, the
engine can get jerky below 2000 RPM under light load -- that's something I
can easily live with by simply not cruising below 2K, or by applying a bit
more throttle as I accelerate up to 2000 RPM.

So here is John's "secret": John recalibrated my TPS to stock settings,
which decreased fuel consumption. He balanced the throttle bodies and other
intake bits. Again, not a revelation. The difference, for my specific bike
and configuration, was to use spark plugs that were one heat range hotter
than stock, and which had a projected tip. According to John, slight
differences in the ignition source can make significant a difference in
combustion and engine behavior. Oilhead owners using the famed "Autolite"
spark plugs swear by them (projected tip), so it's not as though this hasn't
been done before.

My suggestion is to find a qualified BMW boxer engine tuner (not just a guy
who does "tune ups"), and let him do his wonders. One last caveat from John
Parker: The solution that worked for my bike is not a "magic bullet" that
can be applied with equal success to any other oilhead (so don't ask for the
spark plug part number); a qualified engine tuner can help you determine how
to make the best of your specific scenario.

FWIW, I am still a big fan of dual-plugging, but considering the difference
in cost between the work John Parker did on my bike, and the results I got,
and comparing that to the cost of getting a dual-plug upgrade, I am
extremely happy with the results.

- -Steve Makohin
 2000 R1100S/ABS, Mandarin
 Oakville, Ontario, Canada

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