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View Full Version : 04 yfz450 stumble low end



TRX450RACER174
07-18-2007, 09:36 PM
Hey guys i have a 04 yfz with a low end stumble, i read the sticky and no one seems to have the set up we have so here it goes, list of mods is, drop in 13/5.1 piston, lrd pro4r carbon exhaust, pro design intake and every thing else is stock no cams or anything, the jetting right now is 182main, 50 pilot, ndsr needle on the middle clip, it has a low end stumble and i am going to change to a ncvq needle and 42 to 45 pilot any other help is appreciated thanks. This bike is also running on c12 as per the engine builder dont know if that changes jetting much, i work on Honda's mostly just trying to help out my teammate.

250r4life
07-19-2007, 12:35 AM
i put the boyesen quickshot 2 on my bike and love it...

i have an HMF full system, a 48 pilot and the accelerator pump on it, and it runs perfect from off idle all the way up... before the accelerator pump i had the same off idle bog, and sometimes punching it would kill the bike, and most other times it would stumble and i would have to ease onto it...

GPracer2500
07-19-2007, 10:31 AM
If the "low end stumble" is occurring when the throttle is punched then focus on the leak jet. Go smaller.

250r4life
07-19-2007, 10:48 AM
how you coming along on getting your bikes ready GP? we're past the half way mark for the offseason...

GPracer2500
07-19-2007, 12:29 PM
Originally posted by 250r4life
how you coming along on getting your bikes ready GP? we're past the half way mark for the offseason...

I'm making progress but it's slow. I've got almost all the parts together for the CR500. The CR250 frame swap is just a matter of going out there and doing it. I need to get moving so I'm not rushing to get ready for the first trip....

250r4life
07-19-2007, 04:25 PM
get going-hopefully dune season will be here before we know it :D

man, i've been working on bikes so much and am tired of it- im ready to go ride again...

the YFZ & raptor are done and ready, so that is nice... i thought the 250r was ready after i rebuilt it, and it is through 1-4th, but i did something wrong cuz i cant get it to shift into 5th or 6th, so im in the process of tearing it down and will be rebuilding it here within the next week or 2... and then i've still got to do a few things to the 185 i picked up...

but between my bikes, my buddy's bikes, and the 2 odysseys we are customizing (taking them to the powder coater on saturday) for somebody, we've been busy...

MAaudioX10
07-19-2007, 10:04 PM
Originally posted by TRX450RACER174
Hey guys i have a 04 yfz with a low end stumble, i read the sticky and no one seems to have the set up we have so here it goes, list of mods is, drop in 13/5.1 piston, lrd pro4r carbon exhaust, pro design intake and every thing else is stock no cams or anything, the jetting right now is 182main, 50 pilot, ndsr needle on the middle clip, it has a low end stumble and i am going to change to a ncvq needle and 42 to 45 pilot any other help is appreciated thanks. This bike is also running on c12 as per the engine builder dont know if that changes jetting much, i work on Honda's mostly just trying to help out my teammate.

All I did was go from a 45PJ to a 50PJ. Had a horrible stumble on the bottom end. Currently, I don't have ANY at all!