Carb Problem
 

Hi all
I've got a problem with my 2003 XT, I have changed the can and link pipe to a GPR one but now it pops and farts like mad, it pops on the over run a little and just dies at about 4000rpm, I have leaned the mixture till it backfires through the carb, then tried to richen it at a 1/4 turn at a time but no joy.
Any help would great.

Mike:confused1:

Sounds like you are still way too lean and a serious pilot screw adjustment is needed.

A good explanation is here:
http://www.horizonsunlimited.com/hub...379#post283223

You can find plenty of others with a search.

The XT should be jetted rich enough to cope with a new exhaust. Start with the simple stuff - pilot screw adjustment is free. And doesn't need the carbs extracting. From memory you can go about 6 turns out without the screw dropping out.

Just be careful - it is easy to burn you hands in there as there is very little space. Some nitrile gloves should help a bit.

Why did you lean it out ???

Like said, you need to richen it up to deal with the exhaust..

If you're losing power too like you say, you could raise the needle one setting.

Try to adjust the mixturescrew out 3 turns. If it still pops when enginebreaking, go up one size in pilot jet, and start adjusting the pilotjet again.

Well I have tried adjusting the screw at 1/4 turn at a time, but no joy, I have closed it and opened it fully trying to find a mid setting but nothing happens to the revs.
Its a pain, so i,ll order jets and a service kit and start again,
I think it,s running rich as the problem gets worse with the choke and the can is heavily sooted ...:rain::rain::rain:

The popping normaly comes from a untight exhaust. Air is sucked in when you release throttle, and makes the unburned gasses explode in the exhaust.
Try to block the exhaust when it is running a listen for places where it is untight.

Set the carb to standard specs and then raise the needles on or two nothes. That should do the trick.

Check also the litle membrane on left site of the carb. It causes some popping if damaged.

Is this the enrichment diaphragm?

If so, I replaced the one on the previous XT. Its job is to prevent bog down when you open the throttle after decelerating at high revs. Replacing it fixed that problem on that bike.

Good news , the carb parts arrived this morning so its stripped and rebuilt now,bigger primary jet and all other parts renewed.
I now have it close to perfectish on the mix now, will do a long run tomorrow and report back.
Great help and a good forum
Thanks
Mike

All fixed and working now.
Great