Engine seems to idle to high when clutch is engaged

N

Neko

New Member
Engine idles what seems to be to high. just seems to keep rising. Should I make an adjustment to the throttle cable? I have a cjhinese 80cc with the needle carb.

thank you in advance
 
Sounds like a lean condition. A lean condition is certain death for a 2 stroke engine. Check for leaks with a can of carb cleaner by spraying around areas suspected of a leak. Intake, Carb, Head gasket, intake at cylinder.. Spray in those areas and see how it affects your idle. If there is a leak, it will slow the motor down as it sucks in the Carb cleaner. IF you find a leak or leaks, fix it right away or you will burn your motor up. If you find no leaks, then you need to raise you carb needle 2 slots. Hope this helps... Enjoy the ride...
 
hi neko; the cable can be adjusted but it sound like a vac. leak. tighten the intake manifold while it idles, if you can.
 
thank you for all help. I adjusted the cable and made slack so to speak and now it is running like a champ. Doesn't feel so dangerous. Actually use the throttle.
 
For those who haven't had much experience with two cycle engines or motorcycles that have them...........they are quite radically effected by air leaks. A four cycle engine isn't effected quite the same.

It's a common scene when you are around a cycle event where 2 cycle engines
are common to hear the things start running away with themselves like the carb is stuck wide open. An air leak somewhere will do it almost every time.

It is something to become familiar with if you are younger builder/rider as sooner or later you'll experience this situation. Or you'll be around a paniced owner that this is happening to for the first time. But ya gotta locate the leak and shut the engine off in order to tighten things up. (and beware of tightening things on a hot aluminum engine as it doesn't take too much to do the trick) With so many of the motorizing kits coming in from China being two cycle it would make sense to learn about this as soon as possible after you get your bike together.
 
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With these nikasil liner engines a lean run could spell instant death. Learn to recognize a lean condition.
 
So keep an ear out for running. and see if there is a leak? Do I wait until it is excessive or is an occasional race of the engine to be expected. Thanks
 
How do you apply rvt on the carb. I found a spot where it si sucking in air where the carb meets the neck of the engine. there is a clamp but it is incifient.
 
Where exactly is it leaking? On a couple of mine, the cuts in the carb were too deep and when I slid the carb on, it went on until it stopped, but the cuts were still allowing air to be sucked in. I ground them off with a belt sander. If you have to do that, you can use a file, dremel or ??? to do it. No silicone RTV needed.
 
Yeah the cuts are too deep I have ground the nipple off so that I can get the clamp back in there. It never ran away on me. just a little durring idle We will see if this takes care of it.

Thanks for your help
 
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