I just bought an 86 trx 70 for my daughter and it doesnt run very well. It starts and drives but if I get somewhat aggressive with the throttle, it boggs down and dies. I replaced the carb with new and still runs the same way. I replaced the plug, checked for exhaust leaks, replaced the fuel lines and still the same thing. any suggestions?

 

some bikes have a rubber boot that connects the carb to the engine. they can get a hair line crack that you cant see. you might try taking it off and squeezing it to see a crack. also if you have a oiled air filter it might have to much oil on it. the first time i cleaned my sons crf50 air filter i put to much oil on it, and it did the same thing. i recleaned it and it worked fine.

 

also if you get it fixed yet us know what the problem was. thanks

 

yo son if you get yo daughta a yfz or a rappy she aint be boggin down, then she be fly like a straight g.

 

I had also cleaned the air filter. I dont think I put too much oil on it.
I will check the boot. Thanks, Ill post what I find.

 

Hoyt34, I have no idea what you just said.

 

I have the same ATV for my son, and had the exact same problem. I got mine dialed in by the correct combination of the pilot screw and needle jet. The manual calls for the pilot to be 1 3/4 turns out and the needle in the 4th groove, but. that didn't seem quite right (I do live at 6000 ft. altitude). I can't remember what I set the pilot screw at, but I put the needle in the 3rd groove.

 

I have adjusted the pilot and jet screws several times. I know it runs better with the choke on.

 

Has anyone checked the gas take? Mine bogs to ? Could there be something troubling the gas tank?

 

Is it possible that it is points related?

On my ATC70, I ended up replacing the points - and it fixed all of the 'hard idle, dying after running, etc' problems.

also - on the 70 - there is that little filter by the petcock, make sure that guy is free and clear.


-Wayne