I have a 1985 YTM 225 DR that runs good at mid/high speed, but the idle is not as good as it could be. I've checked the air passages in the carb, air filter and played with the air adjustment, but nothing has helped. I decided to try a smaller pilot jet and it improved. I actually put a small drill bit in the pilot jet just to test my theory. Iowa elevation shouldn't effect this condition. Anybody know what size pilot jet is orginal equipment...I currently have a #20.

 

See if Yamaha's parts archives go back to 85. You can find them on there website. Otherwise just call a dealer and ask.

 

The parts breakdown don't go to that detail and the dealer couldn't answer the question.

 

hello, don't know what I was thinking, it shows the size of the pilot jet (#20). I took a closer look and it had been drilled out, put a new one in and it runs like a champ now.