Hello, I just recently put a new piston, rings and head on my sons PW50. Had the entire bike taken apart to clean and lube it. After re-assembly the bike started up fine after quite afew kicks. The problem is when I switch from "start" to "run" the bike goes all out full throttle. My first thought was
a kinked throttle cable. I can still twist the throttle, it just does not increase or decrease the throttle response. I pulled the throttle cable out of the top of the carb numerous times, it seems like it has enough travel.
Maybe stuck? Any help would be appreciated. Thanks!

Check to see if the carb slider is 180 off

did this help? seems mine is doing the same thing.....

Hi, thanks fpor the response. I am trying to figure out what the "carb Slider"
is. Do you mean the throttle valve? The part that slides up and down when you twist the throttle cable? If that is what you mean, then I think it will only fit in one way, but I will check it for sure to make sure it is in the right way.
Thanks

thanks, it is the slider i was talking about. it would not go down because I didnt notice it had a bump on it by where the idle screw goes. I must have forced it down the wrong way that ended up making that bump. I sanded it off and now it drops in sweet! Boooya

I have a PW50 doing the exact same thing. It ran great then all of the sudden it did the full throttle thing going from start to run.

Slide stuck open? What causes slide to stick open?

Thanks!

cleaner1 said:

If you haven't had the carb apart, it could be the throttle tube sticking (the part on the bars - dirt/damage/etc.), throttle cable binding do due dirt or damage, or a dirty slide in the carb.

A leaking crank seal can sometimes cause this too.

also when they fall over the impact will cause the throttle tube to create friction with the bar end and cause it to stick a little. loosen the two screws on the switch and back it off the bar end a little if this is the case.