high altitude jetting issues

[smahala1286]

I recently took my bike up trail riding in the mountains and I was having some jetting issues. I expected it to run rich since I didn't re-jet. Currently the bike is jetted for around 5,000ft. The trail I rode started around 8,000-9,000ft and went up to 11,500ft. The bike idled and started fine. The issue was with the low end. It would bog bad at low rpm's then run fine at high rpms. It made it difficult to start from a dead stop, I had to really feather the clutch. If it was in the low rpms it would bog bad no matter what the throttle position was, I had to constantly flick the clutch to get it higher in the rpms. The bike is a 95 rm125, I know 125's have no bottom end but its not like this at lower altitude. Would this be an issue with the pilot jet? What do you guys do for jetting in mountain terrains? A lot of the trails around here have an elevation change of around 2,000-3,000ft. Thanks for the help.

 

[helio lucas]

you could simple carry a screw driver and adjust the pilot screw on the side of the carb. turn clockwise to richen.

you have some stickies on the 2 stroke forum with many links on carb fine tuning (jetting). read some to better understand the efect of jetting...

be sure to have the carb well clean, the silencer freshly repacked, and all the motor in good shape or any attempt to tune the carb will be useless...