Idle Problem

JimKamenidis

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Jul 14, 2010
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guys please help, my motor runs very well and I like it very much etc.
But from the first day I have a very frustrating but particular problem, when I stop with the clutch disengaged the motor can't stay alive unless i rev it slightly!
Can you please tell me what can my problem be rather than the idle screw?(because I think I have tested that solution!) :cool:
 
@Jim
On top of your carb where the throttle cable comes out there should be a long nut that when turned will pull on the slide in the carb. you can also adjust the nut where the cable goes into the housing on the twist grip housing. Keep in mind a little goes along way. If none of this does the trick you may want to try,(this happened to me out of the box)with the motor off, giving it full throttle and twist the idle screw all the way in. Then let off the throttle and back out the idle screw to an appropriate position. Bon chance!
 
Regardless of the engine type, that normally comes from a vacuum leak if the fuel mixer is not buggered up. So take off the carb and manifold to check the gaskets and seal everything. If the carb slips on to a spigot and doesn't have an "O" ring, you can put some blue silicone on it.
 
Thanks for the replies !
And what position should the choke be at?

Every engine is different, everyone lives in a different climate. I only use 1/2 choke on first start of the day (I purge air out of the carburetor, about 5 pumps). Choke handle up in center. After engine warms up enough (a few minutes or about 500' of riding), I take all choke off. Handle down.
 
Jim, first up. ignore any advice to adjust your idle by tightening the cable. Not good. If you do that, the idle will vary as you turn the bars from side-to-side.
Adjust the cable to allow about 2-3mm slack. (Just enough so that moving the bars side-to-side doesn't quite move the carb slide.)
Then adjust your idle by screwing in the idle screw on the LHS of the carb.
(You should have mentioned what sort of engine you have - I'm assuming a Chinese HT 2-stroke with an NT carb.)

An air leak would cause your engine to idle high, not low, so you can rule that out for the moment.

As Ron said, you'll have to sort out the choke for what works best for you. I use full choke for one attempt, then an attempt with no choke and it fires right up.
 
aussie i don't know your setup but, on mine if you adjust the cable your doing so at two fixed points. If the cable, ie idle moves when you turn the bars you've got some weird unsafe issues going on. The length of the cable remains stagnant regardless of where the cable housing is. By adjusting the nuts on the cable housing your simply applying pressure to the return spring inside the carby, thus pulling the slide up and adjusting the idle.
If it makes you feel any better jim, I had your exact problem when i first built mine. Problem solved and many miles of happy riding. Good luck to ya!!
 
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If the cable, ie idle moves when you turn the bars you've got some weird unsafe issues going on.

No, a cable inner will always pull slightly when the casing is bent.
I'm not making this up, do a test - it's a fact. I'm speaking from long years of experience riding motorcycles.


The length of the cable remains stagnant regardless of where the cable housing is.

Not true - see above. I'll correct this. Of course the length of the inner cable stays the same, but because it's being bent around a circumference it's shorter relative to the outer casing.

As I said earlier, do a test. Don't just try to think out the logic. Believe me, I'm right.

Further to what I just said, I have a question - what is the purpose of the idle speed screw?
 
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