I have a 125cc honda clone atv put new carb on it ran and started good for a few days now it's a b*tch to start when the engines cold I have to raise the idle a good amount just to get it to stay running it'll start up but die instantly without raising the idle choke doesnt do much after its started only works for getting it to run I've adjusted the a/f screw and needle every which way possible did valves they maybe a hair tight but i dont see that making it that hard to start cold especially since once warm it'll start right up and idle at normal rpms it's also a 2 1/2 month or so old engine if that means anything has a PZ20 carb

 

Have you tried cleaning the carb out. A new one can block just as easily as an old one if there is dirt coming from the tank. Also fit a new plug, in case it is a faulty plug causing the problem. After that, check valve clearances, first sign of them closing up will be difficult starting.

 

I haven't cleaned it only because I figured iafter warm it runs fine that it shouldn't be clogged otherwise I'd think it'd not run right at all and I've done the valves but hasn't fixed anything. I've moved e clip from middle to bottom but that just made it bog heavy under about half throttle my next thought is maybe new tank and petcock incase they're pulling something threw fuel filter i've also tried a new plug with no results

 

Gotta agree with merryman. I would clean the carb. Did you put on a new fuel filter when you changed the carb? Reuse old fuel lines? Doesn't take much to clog parts of those carbs.

 

Yeah I put new fuel filter on only thing i haven't changed it fuel lines i have an extra carb I'm gonna clean and toss on see it anything changes and if not i'm gonna try new tank and petcock see if the issue lies between there because this is probably my 3rd carb works good for a few days then i gotta turn idle up to get it to warm up then i can put it back down to normal rpm i have another atv same model runs and starts no problem so I can't figure it out