A couple of Jetting Questions

[ryan]

Well it is definately time to rejet my carb on my 01 CR 125 cause it is waaay too rich at least on bottom end. I was thinking of going down on the main one or two sizes, But I am really not sure which way to go on the pilot? Right now the jetting is stock 380 main, 45 pilot. Would really like some advise!! Thanks, Ryan:confused:

 

[canvet]

Hello Ryan;
The pilot jet and air screw control up to about 1/4 throttle. Leave the main jet alone if the bike is revving out clean. Leave the needle alone if there is no hesitation in mid-range. Lower numbered mainjets are leaner. Lower numbered pilots are leaner. Try dropping the pilot a size, if this helps but is still a bit rich, try another size smaller. Moving your air-screw out will also lean out the bottom. Good Luck.

 

[Ricster]

If you have questions on jetting and tuning a carb in general, Eric Gorr's link and web page have these in depth topic's. I am doing a lower end rebuild with the info off his pages.

_______________________________
Ricster
YZ 250
YZ 80

 

[MXP1MP]

What I ran in my '01 CR was this and it helped alot, #40 pilot with the 2071 (last 4 numbers most important) Needle in the 2nd clip position and left the main stock air screw at 1.5 turns out. this made a big improvement by changing the needle the bike needs it badly! I never got to test it out but I heard the #2171 needle is better than the #2071 needle. This will improve throttle responce once I put in that jetting specs the bike ran ALOT cleaner and bogged ALOT less on the bottom and overall.

 

[ryan]

Well I already ordered a #40 pilot and a 370 main, if this doesn't help enough I give the #2171 needle a try! Thanks.

 

[Adrenaline]

I run a 50 pilot, 20-68 needle, 360 main and a/s at 1 1/4out. I have FMF fatty pipe and run 25 race gas and 75 pump. 32:1 motul 800 2T at sea level. Runs flawless.
ADR

 

[Adrenaline]

one more thing

the 21-71 and the 21-70 needle are so alike. When I was going through what you are the 21-71 didn't do anything. If there is a 21-73+ needle go for it