Hello,
I got a 85 trx 125 yesterday that's has not ran for over a year. I got it up and running today After cleaning the carb out very good. After it has ran for about 15mins it dies and is very hard to re-start. As it is dieing, if I close the choke it will continue to run. But as soon as I open the choke it dies? Can any one help me?

 

I am having the same issue with the ATC 110 in my case what is happening is after cleaning the carb thoroughly the horrible rust in the fuel tank gets back into the fuel line and clogs either the line or the filter that is behind the fuel shut off valve. What I assume is happening is there is not enough fuel going in the carb so restricting the airflow sort of balances it out allowing it to run with the choke applied. I am not familiar with the 125 but it sounds like the same problem.

 

That's funny you machined that. I was wondering yesterday if that is what's wrong. I did clean the gas tank thoroughly before putting gas into it. But I guess there could still be some rust in it. I hope that's all it is. The inside of the carb looks grate so I don't know if it needs a rebuild or not? Does any one know the stock setting on the little screw on the front of the carb? I was thinking like 2 1/2 or 1 1/4 turns out from fully closed?

 

Never mind.... i get her running! I had the wrong gasket between the intake and the carb. Thanks for all the help!