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Old 05-21-2008, 02:05 PM
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Pablo Pablo is offline
Master Bike Builder & Forum Sponsor
Join Date: Dec 2007
Location: Duvall, WA PNW
Posts: 3,649
Default Re: Motor starting to miss

So uphill it "misses"....give me a slight more amount of info...does the engine go flat for power, or does it just "pop" a miss....???

Indeed get a new NGK plug and a nice 7mm auto sp wire with 90 boot.

Then use a good oil at 25:1 or 30:1, depending

What needle slot are you using?

Remember a 67 cc engine is not a torque monster. I think the compression ratio is really low, so again this limits torque - plus worst of all the power band is narrow and you ain't got gears to keep the power in the band.

Also, you can check for intake tube leaks and match the intake and exhaust ports. The intake manifold is a notorious bad match to the port PLUS is has weld protrusion that you can clean up.
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