High idle on 50cc two-stroke?

[soundbeltfarm]

Got a ktm 50cc and i have noticed that the bike is starting to idle a bit high when luke stops and then idle slows to normal after about 3-5 seconds.
what could the cause be?
i am sure i have seen this spoken about before but i can not find it searching for it.

Thanks Karl
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[F5 Dave]

Most likely cause on a fairly new bike is the throttle cable is a bit snagged on something or damaged, or carb crud.
Other than that it could be running lean with an air leak. These will be the crazy auto ktm huh. Man they are loud & seem to rev like crazy. Look like fun though.

[soundbeltfarm]

thanks for the info.
i done a few searches on a couple of other web sites and it seems like i need to turn the air acrew out a quarter turn or look for an air leak from the carb to the manifold.
yeah the bike is loud and it flies.
i am changing the clutch a bit so instead of using the cupped washers for the clutch stack i am getting springs of a ktm mini adventue and using them with a couple of shims so it takes away a lot of the on off engagement and then luke will get used to standing while riding.
at the moment it is like a bloody light switch it either on then bang into power band or not engaged and just idleing.
i went onto ktmtalk and found heaps of info on there.
also i rang a few local ktm dealers about the above and they didn't seem to know what i was trying to do.
i rang patterson oconnor in rotorua i think they are and the parts guy there was awesome to deal with.
he got back to me within ten mins with all the parts i need and prices.

[F5 Dave]

Mark Patterson there is pretty handy with suspension too.

If you want to quieten it down a little a reversal end cap (basically a cap bolted onto the end of the muffler that has the outlet pointing away from the original so it has to reverse) will knock a few dB off it without touching the power. Cycleworks down wgtn make them for some mufflers, easy enough for someone to knock one up.

I doubt many local dealers would have spent any time with small bikes, they just want to sell them & only hear when the lad grows another 6" to trade up. You can see their point I guess.

erm, air screw out on most 2 stroke carbs lets more air in leaning the mixture. Either way you can try it both ways & see if it works. If the screw is located on the airbox side of the slide it is an airscrew & should work as I've described so I'd try turning it in first.