plug gap?

[cam2]

what plug gap are you guys running with? yamaha recommends .028 to .031. i'm using the standard BR8ES NGK at .028 and i was wondering if i could get away with a narrower gap like .022 or .024. i use a 50/50 mix of pump gas and race gas because of my higher compression and +4 timing advance so i thought that i may benefit from the narrower gap due to the high octane fuel that i'm running. any thoughts?

[sredish]

Why do you want to change the gap of your plugs. Technically, the larger the gap, the better the performance, that's why people add high voltage ignitions, to increase spark gap for more efficient combustion. A narrower gap is not what you want. Think of the splitfire and the new Bosch plugs, they have multiple conductors to increase the amount of spark area, which is what you would want, not reduce the spark area.

 

I run my plugs straight out of the box, no gapping or anything and that works perfectly and that's what I'd suggest. If you really want to measure the gap and make sure it's right, I'd use the recommended gap from Yamaha.

[FIRST BANSHEE]

I agree, less gap = less burn = less combustion = less power. plus you will foul your plugs more.

[Ducman]

A smaller gap can help supress detonation if that is a problem but it wont help performance, it can also make the idle rougher. In super/turbo charged cars the only reason they make the gap smaller it to keep the spark from being blown out by all the added fuel and air combined with turbulance and to help supress detonation but a smaller gap doesn't help performance unless it is needed.

[cam2]

i was just wondering if the "higher octane" would cause a little problem with ignition if the plug gap was to big because "higher octane" fuels don't burn as easily as lower octane fuels. there's no doubt that i want a better spark but the "higher octane" fuel got me wondering about plug gap with the stock ignition and standard plugs. the increase in octane probably doesn't effect the plug gap by much or if any at all but i was just curious as to what others thought.

thanks guys.

[95blazer]

I had a problem during my last trip to the dunes, actually it is a problem I have been trying to diagnose during the last 3 trips to the dunes. After a 20-30 minute ride my bike would start to miss like crazy from about 1/2 to full throttle. I would then throw new plugs in and it would run fine for about 20 minutes and then do the same thing. Normally if I let it cool down it would start up and run fine until it got hot again. I had replaced the coil, stator, reeds, messed with jetting endlessly all in hopes of solving this problem. I finally got fed up and took it to get it dynoed and jetted correctly once and for all. I picked it up from the dyno, took it to Glamis and what does it do after 20-30 minutes, you guessed it. After messing with the main jets, and needles some more without any results, a buddy in my group said I should reduce the plug gap. So I pulled the plugs that were missing like crazy and reduced the gap from .028" to .023", I fired it up and it ran perfectly for the rest of the weekend. This was a problem they had encountered before, hence the suggestion. It turned out that my combination of 160psi+ compression, combined with Slower burning VP C-12, +4 advanced timing, and the banshee's notoriously weak ignition, was allowing the spark to be extinguished before it would ignite. Just somethng to think about, it sure as hell made my weekend!!!

 

Derek

[Leadfoot350]

When you use a magneto ignition you reduce the gap. Builders recomend 18 to 22 gap. The stock ignition is weak as hell and with added comp it will get blown out.