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NRPkfx400
06-07-2008, 07:37 AM
I went from an Hmf slip on to an fmf header w/slip on and back to just the slip on. When i just had the slip-on on the quad ran great so i decided to go back to just the slip on. So i redid the jetting to what it was when i bought the quad( used with the Slip-on). I started it up hoping to be back to the way i like it and it was backfiring on the slow down or going down hills. When i bought the quad it was pretty cold and now it is around 90 degrees. Does this have any effect on the jetting or do i just need to mess with the fuel screw. I put the stock 130 Main jet in and the stock 22.5 pilot in(this is what i had when i bought the quad). SO give me your opinion on whats up.
NRPkfx400
06-07-2008, 07:53 AM
Oh yea anyone with a Hmf slip-on lemme know what your jetting is that would be a big help. Thanks alot
drzoo2
06-07-2008, 12:12 PM
I take it the airbox lid is on or it wouldn't run with a stock 130 jet.

Temperature plays a huge part in jetting. When it's cold the air is more dense requiring more fuel. When the temperature changes to warm the opposite is true and a smaller jet is needed. If you had just dropped down a size it may have been ok. Any time you change airflow via temperature and/or exhaust your going to have to make some jetting changes.

z
NRPkfx400
06-07-2008, 02:43 PM
I went from a 170 to a stock 130. The 170 was with my fmf header pipe and went back to stock header along with the 130 jet. ANd yes the air box lid is on.
drzoo2
06-07-2008, 05:50 PM
If you had a 170 in there with the lid on you were way over jetted.
NRPkfx400
06-08-2008, 02:16 PM
It ran Way better with the 170 main along with the header pipe.
NRPkfx400
06-08-2008, 04:04 PM
But that doesnt matter any way i just want to know why it is running funny even when i went back to the original jetting i bought the quad with.
drzoo2
06-08-2008, 05:05 PM
Temperature = smaller jet, Popping = fuel screw adjustment. After replacing the pilot also = fuel screw adjustment. Even though you put the quad back to original other factors have changed. Just go through the motion of jetting it like you normally would. By the way I have an open airbox, Full exhaust and cams and my main is a 150. Any fatter and it would puff and bog from being rich. If you ran a 170 there must have been some air leak somewhere. Thats huge....specially with a close airbox. Is your intake boot ripped?

z
NRPkfx400
06-08-2008, 07:27 PM
I don't think its ripped ill check that later.