Help needed quickly please!

[bsjoe]

Yes, reason why i say i need help quick is that im going riding for the weekend in only a few hours before i go

I have a 04' YFZ450 esr full, run with airbox lid on, 178m 48p 2 1/2 turns out on fuel screw cam mod

gheres the problem, when i would go to full throttle, the rpms rev up and then bounce (full down like 600 rpms, then full again then down 600 rpms over and over basicly)


somone told me to go bigger main, i did that and it does it much faster now..


i have a mic and im willing (im desperate) to make the sound for you if you have aim or msn or somthign where we can have a voice convo... idk what it is help wtf.gif

[bsjoe]

okay, felt stupid doing it, but i recorded it


heres what it sounded like with a 170 main

http://media.putfile.com/b4-23


heres what it sounded like after i mader the main bigger to 178

http://media.putfile.com/after



sorry if it sounds a lil weird lol had a hard time not laughing

[GPracer2500]

I'm still laughing...:p

Seriously though, a 178 is pretty big. Even a 172 is pretty big--especially if you're running with the lid on (and the stock filter?). And since the condition got worse as you went up then you should go in the other direction. I'd try a 165. As an alternative you could try your 172 and take your airbox lid off (if you can do that with the stock filter settup).

[bsjoe]

well the esr site reccomends the setup i have currently and other peopel with the same setup reccomend what i have too

i had the 170 main jet on there before and it was running way to lean... could this be topping out on the rev limiter? somone mentioned that
if so how would i know

[WickedATVer]

Sounds like topping out on the rev limiter does it do anything differant when its under a load?

[GPracer2500]

Hmmm. Could be hitting the rev limiter. With stock gearing I would think it would be tough to hit the limiter in 5th though. What gear are you in when it missfires?

If you hold WOT in 4th or 5th starting from a low(ish) rpm then does it pull cleanly--no misfires?

[bsjoe]

no load on the engine, it did it when i was in 1st and second gear on a flat trail when i first got it, stopped riding after it did it and asked for advice, was told to get bigger main, still sitting infront of my house and i put new jet into it today and reved it in neutral and did that

whats WOT?

[GPracer2500]

Well in that case, it probably IS your rev limiter. You can't fine tune jetting in while neutral and other low load situations.

WOT = Wide Open Throttle

[bsjoe]

k thanks whew thought i was in big engine problem troubles:o