I know...Here we go again....
I put a new exhaust(Supertrapp) on one of my warrior's and my other warrior
got jealous so I had to put a new one on it...
I went with HMF this time...I am extremely impressed..Wished I had put this on the
other one....Anyway, it sounds great and really added some "umph" on the bottom
end(torque/HP)...However, the problem I have now is it "sputters" / "cuts out" when I really
punch the throttle and it sputters all the way to full throttle...I put the main jet in that HMF
sent with the pipe(152.5)...Same result...I adjusted the needle from middle to 2nd lowest notch...
Smae result...I tried a 155 main and the problem remains...The bike idles well and does well
with low throttle..It's just when I "hit it" it wants to sputter and then back fire when I let off...I tried
to get a 45 pilot jet from Yam. dealer and he says they have to be special ordered...Should I order
the larger pilot or try something else...I have tried messing with the fuel and the idle screws to no avail...
Any help would be greatly appreciated...I really like the pipe just wanna make the bike run as well as it
did with stock pipe....is typically said to control 3/4 to full....The plug is greyish black, not wet...And it's not
the parking brake, it doesn't have one....

 

I run a HMF on my warrior with a K&N and open air box and here is what I ran with a dyno jet kit.

Needle on 4th and a 150 main

Started with a 148 but was just a little lean so went to the 150 and ran great.

 

Did you check to make sure the exhaust isn't leaking. If the exhaust gasses are leaking out between the header and exhaust port, or between the header and silencer it'll throw jetting off more than you might think. I know that I had to loosen the header bolts to install my hmf, and although my gasket was still fine, maybe your gasket was damaged from shifting the header, and is causing the leak. A simple way to check for the exhaust leak would be to take something light and fluffy like a tissue around the joints while the engine is idling, and see if any air is leaking out to blow the tissue. The leak could be small enough to not feel the air moving against your hand and still be bad enough that it makes jetting difficult.

 

The magic potion was the following:
Main Jet- 150
Needle- 2nd notch from bottom
Multiple drilled holes(5/16") in air box lid...
Ran for about six hours in all diff. types of terrain and
it runs like a new machine...Very pleased with the sound and
operation of the HMF pipe now....[img]i/expressions/face-icon-small-smile.gif[/img]

 

Did you leave your air screw at two turns?