I put pc t-4 slipon on my 03 250ex now it cuts outs on excelleration , backfires bad on decelleration What can I do. :

 

I have had the same problem. What fixed me up was I was running too rich. I dropped the neddle in my carb. one notch by moving the c-clip on the needle up one groove. Check too see if your quad puffs black some under heavy acceleration aor run it pretty hard for a while and check to see if your spark plug is black, if so you are running too rich. If that fails, make sure your carb. is getting enough air. If the air is being choked to the carb, it will make you run rich too.

 

by just replacing the slip on and doing nothing else, you CANNOT be too rich, it should not effect it much, but if it does it would allow more airflow out which would encourage more airflow in,, ....... your too lean, i had this problem too but i went T-4, lidless and twin air filter, had to rejet MUCH richer to get the acceleration back to normal, the backfiring will never totaly go away, due to decreased backpressure
jetjock16.
in your senerio i would just go up one or two sizes.

 

Generally, a backfire on decelleration means you are running LEAN.

You should do a plug check with a fresh plug to know exactly what is going on.

 

Well guys thanks for the info. I put on new pipe, K & N filter, removed airbox lid. Removed stock 95 main jet replaced it with 102, moved c- clip on needle up 1 notch, it is in middle notch now. There i is very little backfire now on dexcell, But there is still a little sputtering after 3/4 throttle. Do you all have anymore ideas?

 

your main jet is lean....try to go up 1 or 2 more sizes, i think you're getting close to having it jetted right

 

You moved the clip UP??
If indeed you moved the clip UP, you made it LEANER.

If you want the midrange RICHER, you must DROP the clip!
This will effectively RAISE the needle, allowing more fuel to flow through the midrange.

Also, you must do a proper plug check with a NEW plug if you want to know what is really going on in there.[img]i/expressions/face-icon-small-wink.gif[/img]

 

Sand Warrior, read the directions again, when your lidless you are under stage 2 instructions, it will call for a larger jet, i am lidless at sea level with aftermarket pipe, the stage 2 directions call for a 110, unless your at like 8000 ft or higher you still to lean, causing your accell problem, once again i say the backfiring will not go away with the T--4 as it is a straight through pipe, not enough back pressure to totally eliminate it.
Jetjock16.

 

Did your T-4 use a gasket or just metal to metall. The first one they sent me was the wrong one . Wondering if they sent me the wrong one again. This is a slip on.

 

Just metal to metal, and boy did i have to push it on thier hard to get it to fit all the way, The directions i was referin to would be the ones that come with the dynojet kit, you do have that kit right? if not tell me and ill post you the instructions for your application.
Jetjock16