Spark Plug Gap?

discussions specific to the 907IE
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du907
Posts: 346
Joined: Fri Jul 08, 2005 12:00 am
model: 907 I.E.
year: 1992
Location: Winston-Salem, N.C. USA

Spark Plug Gap?

Post by du907 »

Hey, went to the Georgia Mountain BMW rally this past weekend and had a great time. Saw another red '92 907 there. We rode around a little, Deals Gap has really changed in the last 10 years. Anyway, Spark plug gap. I recently put in new plugs for the riding season and set the gap to 0.019 to 0.023 in. as per the workshop manual in General section, on page A.9. I thought while I was setting the gap that it was to small. My engine is not running quite right, not to bad, but not quite as smooth. I have noticed in the same workshop manual in section Electric System on page M.10, it states the gap is to be 0.0275 to 0.0314 in. I looked in the owners manual and it states the gap to be 0.7 to 0.8 mm, which is the same as the 0.0275 to 0.0314 in. So the same "Workshop manual" has two different measurements. What does everyone use? Could the smaller gap cause a misfire?
du907
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paso750
paso grand pooh-bah
Posts: 5568
Joined: Sun Jul 18, 2004 12:00 am
model: 750 Paso
year: 1987
Location: southern Germany

Re: Spark Plug Gap?

Post by paso750 »

A smaller gap can cause a weaker spark, hence there`s less power to ignite the air fuel mixture.
The recommended gap for the P750, 906 or the 750 and 900SS is 0,6mm. 0,019-0,023in are 4,8-5,8mm and I doubt the 907ie uses a smaller spark plug gap than the other engines. So I wouldn`t set it any lower than 0,6-0,7mm.

G.
Tamburinifan
paso grand pooh-bah
Posts: 1543
Joined: Thu Jun 21, 2007 12:00 am
model: 907 I.E.
year: 1991
Location: Gothenburg, SWEDEN

Re: Spark Plug Gap?

Post by Tamburinifan »

I use 0.8, seems to work well.
Gert

907 I.E. -91
M900 -97
MTS 1100s -07
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