by Kiwi » Fri Mar 27, 2009 5:18 pm
Spanish Springs?! That's near my old stomping grounds (grew up in Carson City, went to college in Reno). I still ride with my buddies in Carson (we recently rode at Sand Mountain) and my 2007 450X has ... as runs great with:
-Modified airbox including side slits cut out
-Aftermarket air filter with factory backfire screen removed
-stock idle/slow jet
-172 main jet
-NCYS needle on the fourth position (winter) and 3rd position (summer). Note: NCYS is a bit leaner than the NCVS. Done over I'd probably go for the NCVS.
-CRFs Only idle screw
-Pink wire mod
-Factory exhaust header with Pro Circuit T-4 slip-on muffler
-Aftermarket camshaft
Thus, if your bike is all stock (factory exhaust, cam, etc) with the exception of the airbox mods and aftermarket air filter, I'd suggest:
-stock idle/slow jet
-165 or 167 main jet
-CRFs Only idle screw (about 2 turns out)
-NCVS needle on the third clip position
If you later add aftermarket exhaust, up the main to a 170.
2007 CRF450X with modified airbox, Uni filter w/no backfire screen, NCVS needle on 4th, 172 main, CRFs fuel screw at 2, Boyesen QS3, stock smog, 450R cam, FMF Megabomb header, Pro Circuit T-4 muffler, Pro Taper Evo bars, AS suspension