Idle speed changes from proper speed to fast

[saferider1]

Got a new Taotao Evo ATM150 150cc. When the engine is cold and just started, it idles at the proper speed. After the bike has been ridden a while and the engine is hot, the idle speed increases and the wheel will spin about 5 turns per second when the bike is on the center stand. Any ideas?

[jpackr]

I have an Adly Thunderbike 150 that did the same exact thing. After checking everything from intake manifold leaks to anything else I could check with no success, I adjusted the idle screw to lower the rpm AFTER the engine is warmed up. The next day when I started the engine cold, it idled perfectly. Not sure why it worked but it worked.

[gy6girl]

I had this problem.

I solved it by adjusting the needle on the diaphragm, in the carb.

If not familiar...
Remove the two screws on top of the carb.
Under there is a diaphragm and a big spring, so be careful.
It can shoot out of there.

Pull out the diaphragm.
Inside the tube, connected to the diaphragm, is a single screw.
Unscrew that, and pull out the needle.

You will see there is a clip on the needle that fits into a groove, and there should be like five grooves there.
Note which groove it's on.

What worked for me...
Is moving that clip up a few grooves.

After putting it back together...
Tighten the idle screw on the side all the way, then back it back out a half turn to full turn.
Then adjust the throttle screw to get the right idle speed.

This worked for me, and helped with gas mileage.

Try different positions on the needle as well.
I moved mine to the top, but then dropped it down to the middle groove.

Hope that helps.
Not sure why it worked for me, just learning all this stuff, but it did.