So we had an awesome trip to Dumont and Armagosa. First ride back and I am backfiring and slight hesitation? It was cold (20 degrees) but other than that I haven't changed anything? So it pops and slighly hesitates under load, and only at high revs. I jetted down to DJ175 and lowered down needle one clip from top. Better but still backfiring, also plug showing a bit white on the tip. I don't really want to lean it out anymore, any ideas?[img]i/expressions/face-icon-small-confused.gif[/img]

 

Check all connections where you could be getting an air leak from. One of your clamps/hoses may have vibrated loose.

 

Have you ever rode when its cold before?
Sounds like my symptoms when i was running lean
last winter.

 

Yeah last winter and it was fine! The only change I have made was adding the Dynojet kit this summer.

 

Ya know, a DJ175 is about the same as a Mikuni 165 (stock.) It sounds like you are just lean in general, not to mention cold air is more dense, meaning you need more fuel. It sounds like you need to jet up, way up. Your needle should be somewhere between groove 4 or 5 (you are on #2) your main should be at least a 185 or 190 DJ. Do those two things and I bet it'll run a lot better. I hope you weren't running it that lean at Dumont, your DS sounds like a similar setup to my 2001 which runs a #185 or 190DJ main and the stock needle in the 4th slot as I recall.

 

Have you checked your valves lately? Could be tight on the intakes.
If not the valves then I agree with the "richen it up" consensus

 

Before Dumont I ran DJ180 3rd clip hear at 5000 feet. At Armagosa I ran it the same and it ran great. At Dumont I put the airbox on and it ran ok. But since I came back it pops with the same jetting? I read Dynojet trouble shooting and with my symptoms they say I am rich so that is why I dropped the needle and jet size. Maybe I should go the other direction and see what happens? I checked for loose hoses to the carb and plug wires etc. everything seems ok. Could I have burn't a valve at Dumont by running it lean?

 

Check your battery. The connections can work loose sometimes and that can cause funny things. . . Usually I wouldn't describe it as popping but, worth a check as well.

 

Dune Me I believe you were right, sort of. I took your advice and checked all my electrical connections. I am not sure but I think the cdi connector was loose. All is good again! Thanx everyone for your troubleshooting expertise!