I’m having an issue with my sons Tao Tao cheetah 125. I replaced the stock(restrictive) air filter with an performance one. I also changed the the carb to a PZ22 Keihin carb with 35 Pilot Jet N424-74C style and #88 Main Jet. Since then the engine has an air sucky sound. The bigger issue is no matter how I change the idler screw and air fuel mixture the bike will not idle without dying or having the choke half on. It’s also backfiring. My next step is messing with the jetting. I’m assuming the engine is getting to much air. Since I’m new to jetting which jet would I be chancing and am I stepping the jet up or down?

 

If you need choke on to get it to idle, you need a bigger idle jet, so more fuel. The main jet also affects the idle but if it runs OK off choke once into the "mid range" this would indicate main is not far off. The sucking sound is characteristic of a "performance" air filter.

 

would changing the the idle and main fix the back firing and boggy throttle? You are correct if I ride the bike with half choke it performs enough to be ridden. After about 20 minutes like that I can take the choke off and it will run as long as your Hitting the throttle a little. If it idles for to long it will shut off

 

If you need choke for it to run right once off idle, you need a bigger main jet. Change jets one at a time, and try the bike out before changing the other jet. Most bikes with carbs won't idle for too long before stalling, being singles, one misfire at idle is enough to make them stall.

 

I changed the idle Jet from 35 to 42 and now the bike idles good. My main jet is the same 88. I don’t feel to much of a lag but I may go one size up to try. It still back fires a little. once you let off the gas from running wide open or close to wide open for an extended period of time

side question I have the Tao cheetah 125 2020 when I limit the throttle with the screw for my son it loses power when turning right. I’m guessing it’s the cable the throttle cable. If so is there a fix. If I take the limit screw out and let the throttle have full range that problem does not exist. Any suggestions or has anyone seen this?

 

The limit screw, if fitted, shouldn't make any difference. Are you sure you haven't adjusted the cable length screw by mistake? That is the one on the outer cable coming out of the box on the handlebars. If it has one, the limit screw is on the front of the box.

 

for sure I am adjusting the limit screw. The cable does not have a screw. I’m leaning towards the cable be too short because without the limit screw it does not behave the same if I can load a video I will.

 

Most quads I have come across either have a cable adjuster on the control box or on top of the carb, on the end of the outer cable, many have both.