spark plug gap makes a big differnenc.....

[borntofli]

Have been struggling with this engine for a while..... Long story short... It turns out the problem was the plug was gapped at .018 , and when I regapped it to .028 zooom zooom zooom..... I must have dropped the plug.....

 

[bluegoatwoods]

I'm glad it turned out to be something simple and easily fixed.

Plus it's a good reminder to all of us to not forget the simple things.

 

[maniac57]

Yup. Always remember the basics.
Fuel
Spark
Air.

 

[paintgun]

I'm wondering if that's not what's wrong with mine. Having 4-stroking problems. It's still in the break-in stage. Only a week old with around 20 miles on it.

 

[bairdco]

i did some experimenting a while back. gapped as low as .010 and the bike stil ran, but barely.

went as high as .050 and it still ran. barely.

between .020 and .040 there was no real difference.

optimum seems to be .025-.030.

stock 66cc.

 

[biknut]

i did some experimenting a while back. gapped as low as .010 and the bike stil ran, but barely.

went as high as .050 and it still ran. barely.

between .020 and .040 there was no real difference.

optimum seems to be .025-.030.

stock 66cc.

I agree, and further I recommend not making the gap any more than this because it puts demands on the magneto coil that will shorten it's live.

Too much gap when running a stock magneto raises the current draw enough to burn up the magneto coil at sustained high speed running.

Now I run about 0.025" gap with no problems.

 

[paintgun]

As soon as I get mine back ride-able, gonna gap the plug at .025. It's at .018 right now.

 

[allen standley]

I concur! I do a 25 gap.

 

[maniac57]

I got to thinking about how I always eyeball my plug gaps and decided to check all my junk to see where my eye was.
Four engines, four plugs between .020 and .030!
Guess doing it long enough gives decent repeatability.
(I do still have a plug gapper though I hardly ever use it.)

 

[paintgun]

Well, I gapped my plug out to .025 and it seems to run a little better now. Still have the stock Chinese junker. NGK next week. The 4-stroking is not as bad now. A bit more power than before. Not a whole lot, but noticeable. Again, she's still in the break-in stage. Time will tell.