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Main Area => General GS500 Discussion => Topic started by: addison on April 20, 2007, 10:44:48 AM

Title: Plug Gap
Post by: addison on April 20, 2007, 10:44:48 AM
I have a 2004 F and changed the spark plugs out and gapped the new NGK's to the owners manual specs of .09mm. That gap is HUGE. Anyhow, I could not get the bike to start with that large of a gap. So, I pulled the gap to .03 the same as the ones I took out that the dealer had installed when I bought the bike and it starts up fine.

Am I doing something wrong?
Title: Re: Plug Gap
Post by: manofthefield on April 20, 2007, 11:39:49 AM
are you mixing up metric and english units?
Title: Re: Plug Gap
Post by: addison on April 20, 2007, 11:47:05 AM
Hmmm...don't know. The book says .09mm and I bought a gap tool from the bike store (looks like a silver dollar) and it had a .09, didn't look to see if it had mm after it. Guess I need to check that out because the gap I had it was outrageously huge!
Title: Re: Plug Gap
Post by: gsJack on April 20, 2007, 01:36:53 PM
GS500,E,F spark plug gap is .035" for all years, from NGK:

http://www.ngksparkplugs.com/part_finder/motorcycles/step4.asp?id=2380&type=reg

.09mm/25.4=.0035"    It must be .9mm in metrics.

.09" would be way too big and would not start.

.03" would run, but .035 would be better per NGK specs.
Title: Re: Plug Gap
Post by: sledge on April 20, 2007, 02:22:51 PM
I will go with Jack and the Man, and say you are getting the units or the decimal points mixed up.
The manual states the Plug Gaps as being:

In metric....0.8-0.9mm
In old money....0.031-0.035" (or 31 to 35 thou`).
Title: Re: Plug Gap
Post by: addison on April 23, 2007, 08:07:14 AM
Yup...I was looking at the inches side. Amazing what happens when you flip the gap tool over! Now I feel like a retard, lol

Thanks for your help....