Backfiring

[EXerHonda400]

Somewere around october, i crashed my quad and i am just now getting to do the work on it that it needs. I replaced one a-arm, and a tie rod. But now i am getting a backfiring problem, it is backfiring through the carb and through the pipe. I have checked my valve clearances and i have cleaned the carb twice and the pilot screw is in the right position. I was thinking that the timing was off, but i am not sure. Any help at all would really really really be appreciated. THANK YOU VERY MUCH:)

[Cody_300ex]

Your propley running lean. Might want to do a plug check.

[cals400ex]

what kind of bike do you have?
what are your modifications?
what size pilot jet you using?
where is the fuel skrew located at?

[2004TRX450R]

Sounds like you are lean. Make sure that when you crashed you didn't dammage any of the intake track including the white pipe that goes from your air box up under the tank and make sure it isn't disconnected anywhere. You may need to screw out the pilot screw a little anyway even if it is at the spec it calls for.

[EXerHonda400]

I have a 400ex with an R4 Pipe, i have also put in a K&N Power kit, wich includes the main jet, but not a pilot jet. My pilot screw is at 3.5 turns out which is what the book calls for. All intake tubing is fine and undamaged. THANKYOU

[ReconRider25]

you mightve shook something loose in the electrical system. also, if its been sitting for a while, try putting fresh gas in.

[Joecool1264]

Check your exhaust/ silencer connections. Mine was sucking air though a connection point, a friend showed me, we tighted it up problem solved.

[Greg Z]

make sure your CARBURATOR is on tight!!! make sure there is no little gaps. When i was working on my carb for a bit it was like that and i noticed in like 2 min that my carb was ON but it wasnt on tight and it wasnt far in the boot and it would pop evrey so often so check that

[cals400ex]

what size main did you put in?
if your have a dynojet kit, i assume your using their needle too. where is the clip located on the needle? is the washer under the needle or did you leave it out?

[mustang93]

Originally posted by EXerHonda400
I have a 400ex with an R4 Pipe, i have also put in a K&N Power kit, wich includes the main jet, but not a pilot jet. My pilot screw is at 3.5 turns out which is what the book calls for. All intake tubing is fine and undamaged. THANKYOU

3.5 turns out :confused: :confused: :eek2:

[EXerHonda400]

The size of the main jet is DJ146, and yes i did put the needle in, and the clip is 3rd from the top, also the washser is on top of the needle as the instructions called for. THANKYOU to all who have been responding.

[mustang93]

are you running an air box lid? if not you need a DJ170 main...
I woulnt run the stock piolet w/ the mixture screw at 3.5 I would get a larger piolet (42) and run between 1 to 2 turns out.. 3.5 turns is past the max recomended for the stock carb.

[cals400ex]

yep, i would put in a 42 pilot jet. right now i have a 42 pilot jet in at 2 turns out from lightly seated on the fuel skrew.

[Mongo]

Sounds like you have water in the fuel lines........ Try cleaning the petcock, Line, put new filteron THEN... clean carb.

Ron