Help Please - 34L "popping"
 

Hello all,
Im on the road and my bike is worrying me. Firstly i think its overheating, but im not sure, how the hell do i know- when i touch the engine its very hot and it hurts. Also, on the open road she rides well, when i slow down to 2nd / 3rd gear range (ie slow ridng) it give little backfires, not shotgun blasts, but popping sounds when i decelerate to change gears. Been fiddling today with pilot screw, and i thin k its a bit worse now. Also, usually its a bitch to start her in the morning but today she started ok and later on was difficult to start when hot.

Help!
Jim

Your symptom are those of an over lean mixture.

The popping when you close gear is called over run and while it is normal of large singles, popping is the sign of too much air in the fuel mixture..

Tell me, does this occur at closed throttle only ??

If it is hard to start, is this even with full choke ??

There are many reason for hard starting and a lean mixture is one of them.

You could try unwinding the pilot screw a little and trying then. If adjustment doesnt help then a larger pilot jet maybe required.

Have you changed the exhaust system or air filter etc ?


Wind the pilot screw in until its seated (not too tight now) and then unwind 1.5 turns and start from there.

The XT is aircooled so yes it does get hot. Check your oil is bubbling though. You can buy oil temp guages which replace the oil cap.

Leaks or settings
 

Jim,

We meet again?

If she runs fine for the rest I would not worry too much. Even if the idle mix is too lean, this has no influence whatsoever on the mix with open throttle.

- Is the popping only when you close the throttle? If yes, there's a hole somewhere in the exhaust system or the enrichment device is gunked up. It's the thing on the l/H side of the left carb, little cover with the vacuum operated valve, vacuum from the throat of the second carb.
- If there is popping, with the engine not pulling at the same time, your mix is indeed too lean, but as carbs do not get offtune by themselves it must be something like the intake rubbers leaking air, that's the black thingies between carb and cilinder head.
- Hard starting: Adjust idle mix: heat up engine. With a flat screwdriver turn in pilot screw till engine speed drops, then turn out till max engine speed is reached. do this slowly, gove engine time to react. The higher engine speed will be over a range of screw settings, leave it just before the point where the speed starts to drop again. This setting should give you good starting with cold engine, full choke

Succes! and happy travels!
Auke

mixture
 

Hey Jim,

Not good to hear you having problems so early in the trip! Where about are you guys now? I definatly agree its a mixture thing, Mac,(bryan) bike does the same thing ansd its very lean, my bike however i feel is running slightly rich, this never gives me hastles to start when cold, but can be a little tricky when the bike is hot. i normally just use a little patience and wait as opposed to kicking new vents in my boots! Are you guys still in S.A.? will give you a call if you are!

All the best, regards to Anniken!
Cheers,

Chris:scooter:

Thanks Guys

Turns out there was an air leak in the intake rubber, which fortunately I had a spare of.. She's running pretty now!

JIm