Jetting after pipe & silencer

[shawn900]

I just put an FMF SST pipe and FMF shorty silencer on my 01 CR 125 and was wondering if I could get some recomendations on what to change my jetting to. It is all stock except for the pipe and silencer. My neighbor suggested 50 pilot, 370 main, 2nd clip, air screw at 1.5 turns out. Oh and I am at sea level or right around it. I really haven't had a chance to ride it except for once and the inside of my number plate had quite a bit of black spooge on it if that helps. I would appreciate any input. Thanks

 

[skhasky]

the 50 pilot and the 370 main sound right. So does the 2nd clip. I would however change from 1 1/2 to 2 1/2 turns on the air screw. Basically, it sounds like it is set rich on the bottom. Turn the air screw out 1/4 turn at a time until it doesn't stumble at 1/16 throttle. Basically, warm it up and bring it up to about 4,000 RPM in second gear. Now, close the throttle and let it drop to about 3500RPM and whack the throttle open. If it wheelies it's perfect!If it hesitates and crackles, it is rich - so turn the airscrew out another 1/4 turn and try again. If it bogs (Buwaaahhh) then it is lean, so turn the screw in a quarter turn. When it is right, that bike will tool around at 1/16 (just a crack) open on the throttle with the sound of a bumblebee, not a crackling/popping (rich) or heavy breathing (lean) sound.

Good Luck!

 

[skhasky]

One more thing... how cold is it out there? If it is as cold as I think (40's) then you may need to use the 380 main for now and the 370 in the summer. You may also need to set it at 3rd clip with air screw around 1 3/4. I forgot about that cold-dense air!