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View Full Version : What jetting would you suggest I start with?



IQRaceworks
05-12-2010, 11:57 AM
What jetting would you suggest that I start with? I've seen several guys with mods identical to mine, and it seems like the jetting really varies a lot.

Stock 2005 motor (all new internals), cam mod, full Yosh RS-7 exhaust, Boysen Quick-Shot pump cover, stock intake with K&N and no airbox lid.

I bought this YFZ with a locked up motor, so it wasn't running when I got it. The previous owner said he jetted it and it ran good.....but who knows.

Currently it's got a 158 main, 42 pilot, and the stock needle (I think) with the clip in the middle....3rd position I think. When I pulled the motor apart, the top of the piston and head looked pretty black...so I don't think it was lean.


From what I've seen...some guys with these mods are running as small as a 150 main, and some go as big as a 168 main. The pilot jets all seem to be around a 42-45.

What would be a good starting point? I'm at 900ft.

Thanks!

02bwraptor
05-12-2010, 06:01 PM
Main jet ? 150
Pilot jet ? 45
Needle ? OCFHN
Clip position - #2
Idle mixture screw ? 2 turns out.

i got this from gt thunder http://www.gtthunder.com/Jetting.html

250r4life
05-12-2010, 07:06 PM
i would think you would be somewhere closer to a 170 mj, and a 45 or 48 pilot...