300ex backfires

[DGR]

hi
when i release the gaz on my 300ex , it makes somes backfires. what should i do to solve this ? i turned the fuel screw one turn but it seems to help only a little bit. What should i do:confused:

[TheFontMaster]

Check your pipe to make shure there's no cracks or leaks.

[DGR]

there's no exhaust leak
:confused:

[300ex_rider1121]

check ur spark plug... when mine back fired it had a dirty spark plug

[JDiablo]

you need to re-jet from what it sounds like you are running lean.....i most likely mistaken because i suck at jetting so get a better opinion on this then mine...but you need to go up on your pilot:confused: :huh

[DGR]

no it'S not the case ... i really think it's a jetting issue ... what should i do to solve this ??? maybe the pilot jet is too small :confused:

[bradley300]

you need a bigger main jet, find out what size is in your quad right now and go buy the next five or six sizes bigger and start trying them out, start with the smallest first, go until the motor cuts out on top end at full throttle/high rpm, then gop back 1 size. should do it

[ghak99]

Originally posted by bradley300
you need a bigger main jet, find out what size is in your quad right now and go buy the next five or six sizes bigger and start trying them out, start with the smallest first, go until the motor cuts out on top end at full throttle/high rpm, then gop back 1 size. should do it

Bradley300 might be right, but I have heard and personally had poping while decelerating and it was a lean condition with the pilot jet. The fuel screw helping some would also lead me to believe that the pilot jet is too small, or starting to plug up. You might give your carb and jets a good cleaning first.

[300ex_rider1121]

just check the ****ing spark plug thats wat was wrong wit mine but go ahead and waste money triying to fix the wrong ****ing thing

[Out_Sider]

Originally posted by 300ex_rider1121
just check the ****ing spark plug thats wat was wrong wit mine but go ahead and waste money triying to fix the wrong ****ing thing

dude, calm your *** down. i'm sure he'll get a new plug along with doing the jetting changes.

[DGR]

yes i will change my plug but it is NOT causing the trouble ...
:rolleyes: what pilot jet size would you recommend me ?? stock is 38 .