spark plug gap

gian · #1 11-06-2009, 01:07 PM

is there anyone who could help me to find the correct spark plug gap, i dont have tools for measuring the gap ,maybe i could use any cards but i dont know what are their thickness

Venice Motor Bikes · #2 11-06-2009, 02:32 PM

Some people run the gap small (.024 - .028), But I run mine @ .030

bairdco · #3 11-06-2009, 02:38 PM

i run mine at .30, too. there's no accurate way to measure without a gapper or some feeler guages.

you can walk into any auto parts store and they usually have a candy jar full of plug gapper wheels on the counter. they're like a buck or 2.

Pablo · #4 11-06-2009, 02:51 PM

Real cheap. .99$

I find larger gap doesn't add a thing. 0.020-.025" is fine. Norm runs around 0.015".

Venice Motor Bikes · #5 11-06-2009, 03:02 PM

I haven't seen any real performance difference in small or big gap on these engines either...
From what I know, a smaller gap is suppossed to be better for higher RPM's & a bigger gap is better for low RPM & idle quality.

I just run mine on the big side, (but not too big) because I figure a bigger spark spark equals a better burn...

**BarelyAWake** · #6 11-06-2009, 04:35 PM

Another .030 here... I dunno why, it just is.

GearNut · #7 11-07-2009, 12:32 AM

A typical business card or matchbook outer cardboard is about 0.018" That'll get you close enough if you fit it a teensy bit loose.

xlite · #8 11-09-2009, 09:24 AM

There is a significant difference between small and large gap. In dyno testing large gap gives measureable increase in performance (saw this myself) but fouls easier. Small gap runs better with fouled plug but slightly less power.

When plug gets dirty and misfires I've got home by knocking the gap down. Also had to decrease gap during experiments with light on the white wire.

I use any old piece of Harbor Freight stainless safety wire (.031") laying around to gap mine.

**Norman** · #9 11-09-2009, 10:18 AM

here is some thing I do to the china spark plugs and I run a gap of 0.017 to 0.020 on them.
I was told abut this by a guy who does chain saw racing says it uncovers the flame Kernel for better combustion does it work? Beats me I do it for fun.
If you guys want to build a dyno testing system there is plans on the net to make one using a hyd.pump and assorted material I think it was on a racing kart forum I've see it and down loaded the plans years ago but never did make it. I guess I should have. I'll try to do some looking and see if I can find a link you guys might be able to do the same if your wanting info on a homemade dyno.