My god grand daughter has a 125 Yahama that her dad put water in the tank (another story). This happened about three months ago and cleaning the carb fixed it. This time I have cleaned the carb VERY good and several times. Currently idles very good, start pushng the throttle and it rev's up a small very small amount and goes dead. Re-starts before you can get off the start button. Smother carb opening some and it will rev on up as long as it is being hand chocked like this. Once you remove you hand from the front of the carb it will slowly cut back till it goes dead.

I had a small engine shop twenty five years ago, but never was much of a motorcycle mechanic. Knowing all engines need fuel, air and fire to run, most engines will typically have the same or simillar problems. This atv seems to be leaning out or starying for fuel. Since having the carb off four / five times I have yet to find the problem. Could float level be to low?

If anyone has any helpful info I would really appreicate the help. I need to know this info too; How many turns is typical for the idle jet or thats what I think it is at the front of the carb on the bottom.

Thanks,

 

typical yamaha horror story. mine had carb problems too. the stealership rebuilt it part by part and it is ok now. runs like a champ.

 

first step- drain the tank
second step- flushthe lines with some b12
third step- check your high speed circuit (main jet), float level, and clean the carb
fourth step-re-fill with clean gas and pour in a quarter of a bottle of heet, available at part stores

 

adjust the float and make sure that you dont have any vaccuum leaks.