[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Spark plug advice

In a message dated 3/14/05 11:52:20 AM Eastern  Standard Time, 
dr.ben@xxxxxxxxx writes:
<<A local knowledgeable R1100S  owner has recommended using Bosch FR7LDC which
matches NGK BKR6EK.

The  NGK plug nomenclature is: 14 mm thread but narrow hex (16 mm),  resistor,
coolish, rather long reach into cylinder (19 mm) and 2  electrodes.

My own poor sense is that The Factory wanted a long-lasting  plug and so
wanted to experiment with multi-electrodes which have no other  benefit and,
as I understand these things, have no or negative consequences  for
combustion (Kent, are you there?). Maybe that's why a plain vanilla  Autolite
works better.

By contrast, my poor sense is that a fine-wire  electrode (which necessarily
means precious metal types) can slightly  facilitate combustion by allowing
better flow and swirl around the spark. I  suppose Oilhead dual-plugging
helps because of poorish  combustion.

Well, now that I have an idea of the geometry, I'm thinking  of looking for
the fine-wire Iridium single-electrode, BKR6EIX-8 (that's a  fine-wire
Iridium with a .8mm (.032") gap).

Hoping no flame wars  ensue, but I'd like to hear reactions. Thanks.>>


I went around the horn the first year I had my S,  trying every "wonderful" 
spark plug recommended on various oilhead and S lists.  Every time I put in new 
plugs the bike ran real well for about 700 miles, then  all the symptoms that 
I hated were back, the vibration, slight surging and a  cyclic pulse that was 
going through the chassis that would appear for ten miles  then disappear for 
a week. 

The final cure for all the  problems was to replace the driveshaft, fix the 
left timing chain tensioner,  install the Techlusion 1030I ( I still hate that 
poorly-made POS) and eventually  I forgot and pur stock plugs back in. Now, 
with 37,777 miles on the clock, my S  runs like it should have out of the box. 
It makes great power (first and second  gear wheelies are a twist away) and 
gets steady 39 MPG. (US Gallons for you  frozen Canuckians). The vibration has 
just died out.

Udo Gietl tells me that the real bugaboo of the S motors is the (as he 
describes  it) ten-mile-long timing chains. He says that they stretch inconsistently 
and  make valve timing a joke. Of course, being a race tuner, he values 
accurate  valve timing over all else. It is the holy grail of engine building. 
Apparently  he uses well-worn timing chains that are all stretched out, so that he 
can set  the valve timing and it stays set. Since I don;t have te time ot 
strip my whole  motor and find a couple played-out chains, i did it the easy way. 
I just rode  the bike until the chains finished stretching, then reset the 
valve timing.  (That's a PIA job, BTW)

OTOH, when Udo asked me if I  wanted some hop-up tips for my R1100S, I bit 
and said "sure". He sent me a  picture of a Honda CBR600RR. A regular wise guy.

Tom Cutter
Yardley,  PA
Rubber Chicken Racing Garage T-shirts coming, inquire here...