In the latest issue of ATV Action (pg 119), they recommend some fixes for the cold blooded starting of the 90. Like, turning the mixture screw in 1/2 turn, and a larger pilot jet (that was PILOT not main!!!). This makes sense to me!! I think the bike is jetted LEAN ON THE BOTTOM, and RICH ON THE TOP.

My reasons for suspecting lean bottom are the hard starting (won't start even in hot weather without the choke, and even then you have to nurse the throtle for 5 min until it is warm). My reason for suspecting the rich top end, is that the plug is always black when I change it. Anybody got an opinion???

 

Check your intake valve sounds like it is tight. My boys ATC70 when it gets hard to start the intake is tight.

 

Yup you got it...a little more pilot jet and your machine will purr like a dream...jetted lean to pass emission standards...happy re-jetting

 

Brand new to the trx90 scene. What size pilot jet are you using? Are you drilling it out or just buying the next larger size. Any other reccomendation for a new trx'er dad! Any suggestions appreciated! I would like to resolve this with both of mine soon!

 

Does any one know where I can get the next larger jet. I have checked with different dealers and no one can help me.
I am Lost

 

pm me if you havn't found the jet