Back firing 400ex from a slip on pipe.

[kuz400ex]

I have a 400ex with a white bros. ref box and an E-Series slip on pipe with 10 disks.With the pipe on I noticed that their was alot of back pressure, back firing from the bike every time I was going down a hill with out the gas on. So reading the instructions from the pipe I jetted the carb with a 160 main jet. I am still getting the back pressure. I need some other suggestions to help get rid of the back pressure back firing.

[Guy400]

Richen the air/fuel screw in 1/2 turn increments and see if it gets better. Also check for exhaust leaks where the slip-on and head pipe join.

[AtvMxRider]

I'm with Guy check for an exhaust leak. Mine doen the samething when I installed my e-series.

[250x#93]

Yup I had a dg pipe that was a slip on and it leaked around the head pipe a lot and it when pop pop pop CRACK!!!!!!!! pop pop all the time. But when I got my t-4 it fit on my head pipe nice and tight:devil:

[cals400ex]

why don't you go get a new exhaust gasket like one that comes on the bike from the factory. it will slip over the end of the header and will give you a nice tight fit when you put the silencer on. i think these gaskets may be around $10 at a dealer.

[kuz400ex]

I have checked for leaks all around the slip pipe and came up with nothing. I turned the air mix screw in 1/2 turn and took off the air box lid also. That helped alittle but I will have to keep tunning it i guess.

Thanks guys

[White_Knuckles]

Popping is a lean idle condition. Turn the "air" Fuel screw out to richen. Really! 2 and 1/2 turns out to start if you have the stock pilot jet.

[mcmike]

It's an exhaust leak. Pay real close attention around where you have your clamp. If yours is like mine and everyone else I know, the the clamp isn't wide enough to seal around the expansion cuts. Or its cracked around where the pipe welds to the base of the silencer.

[bandit390]

The exhaust gasket from honda will be to big to fit inside the E-Series slip on. I used exhaust repair kit, from any wal-mart/etc. It fixed the problem.

[RIjon]

Use RED RTV

I had the same problem