Any suggestions on rejetting for higher elevations,  6000-9000 ft. ASL?

You could go lower on the main jet, and if that doesn't work (enough) change the needle.

 

''Normal'' procedure is for motorcycles:

1) idle,
2) pilot screw
3) slow or pilot jet
4) main jet
5) the needle
6) accelerator pump (if equipped).
7) read the plug.

http://www.jetsrus.com/FAQs/FAQ_rejetting_101_how_to_rejet.htm

 

Temprature and humidity also have effect.

Edited August 27, 201511 yr by crazybond700

 The first thing you do going up in elevation is go to a lager pilot.

 The first thing you do going up in elevation is go to a lager pilot.

 

You mean smaller?

 

 

For 6 to 9 thousand feet at similar temperature to sea level i think the corrections are about 0.92, so multiply your jet sizes by 0.92 and that roughly gives the sizes you will need.

 

Dropping the needle a clip would be a good start.

You mean smaller?

I think he means larger, as in bigger !

You mean smaller?

 

 

For 6 to 9 thousand feet at similar temperature to sea level i think the corrections are about 0.92, so multiply your jet sizes by 0.92 and that roughly gives the sizes you will need.

 

Dropping the needle a clip would be a good start.

 Quit reading a book for jetting. I live at 6500 and ride mainly from 7000 ft to 13000 ft. Dropping a needle only at altitude without jetting does zilch. You go up in pilot jet size (Loss of atmospheric pressure if you have to have some logic) down on the main jet. Also riding at elevation is very hard on water cooled trials bikes as the cooling system cannot handle the demands on the motor.

 Quit reading a book for jetting. I live at 6500 and ride mainly from 7000 ft to 13000 ft. Dropping a needle only at altitude without jetting does zilch. You go up in pilot jet size (Loss of atmospheric pressure if you have to have some logic) down on the main jet. Also riding at elevation is very hard on water cooled trials bikes as the cooling system cannot handle the demands on the motor.

 

Its been a while since ive read such misinformation on carburettion. Maybe YOU should read a book on how carburettors work, and while you're at it Aristotle's Mechanica for an explanation on torque.

 Yes there was a time I was stuck thinking that way. Seems about `96 I started jetting my mikuni`s with a 30 pilot. During my rev 3 years I even had a few bikes running a 35. Now a days the Keihin on the gasser gets a 120/ 50 combo at home. About 8000 I switch to a 115/50-55. Above 9000 a 110 main. At about 3000 feet I go back to 125 and 48. Also remember the bikes have come with too lean of pilot jet stock for many years now. And we are talking trials motorcycles. 

L is right on this one. Live and ride at the same altitudes and went from 45 to 55 on the pilot, second clip and from 125 main to a 110. Runs great from 4000 to 12000 feet. 12 Raga 300.