Thread: Rough Midrange
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Old 08-13-2008, 07:53 AM
Bikeguy Joe Bikeguy Joe is offline
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Join Date: Jan 2008
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Default Re: Rough Midrange

Originally Posted by Hicksy View Post
I'm running in my 66cc beastie, it's only got 80km on the clock at the moment.

She fires up easily enough using choke, within 2-3 mins runs well with choke off.

Low range pulling is fantastic but when I get the speed up it sounds like it's faultering. Almost like it's only firing every second stroke.

The plug has no residue on it, still shiny silver, running 20:1 mix, blue smoke at mid throttle to WOT.

Any ideas???
Break-in is best accomplished with the use of various throttle positions and engine speeds- don't be afraid to run it up once in awhuile, it's not going to grenade just because it's new. Baby-ing a new engine will not help in any way.

Now, these engines are piston ported crude old school engines. You are a little rich in the mid range from the sounds of it. These engines will break into a four cycle when they are not loaded (going up hill/speeding up/ect) if they are set right. If you are trying to speed up from mid range and it still is four cycling, you are too rich. If it breaks into a clean two cycle with application of throttle, you are in pretty good shape.

In my experience at least, if you get these things to run in a nice clean two cycle all the time, they are too lean and suffer not only in power, but engine longevity. (wristpin, bottom end bearings).
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