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?

are you mixing up metric and english units?

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!

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.

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`).

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....