Sudden carburetion issues with KLR 650?

Howdy all,

My KLR has been running smooth since I purchased it and did a thorough carb cleaning about 18 months ago.

A couple of weeks ago I was riding my '01 KLR 650 (about 6000 miles on it now) home from work and it stopped dead with no warning about 30 yards from the garage. It was as if I'd bumped the kill switch. I was in the middle of a 90 degree right turn into my cul de sac. Attempts to start up again were unsuccessful -- the starter was turning, but it wasn't catching.

Since I was already planning a tune up, I went ahead and pulled the tank off, changed the plug and oil. While the tank was off, I noticed that the radiator fan blades were worn on the back then saw that the wire bundle that powered the fan had been completely cut through. Figuring this was the reason for the sudden stop, I repaired the break and put the tank back on.

I tried starting again. It caught this time, but only if I rolled on the throttle and kept the rpms between 2- 3000, and then it sounded rough, back-fired, and was blowing a little smoke. If I let the rpms drop below 2000, it would just die.

I pulled the plug again and it was all black at the tip as well as the bottom 4-5 threads, but didn't feel oily. I also double checked the wire bundle I'd mended and it was fine (I've tested that it will come on when the engine is warm). I wasn't sure where to start looking at this point so I took the carb off and gave it a once over. Nothing there that I could see. When I got everything back together again this time, it started readily and idled ok (little rough?) but rolling on the throttle had to go slowly and starts to die at 2000 rpm. Almost the opposite of what it did after the oil and plug change.

I have yet to check the air filter.

Any thoughts what might be going on? I'd rather fix this myself if I can. Local shops are booked out 4 weeks...



Check the battery cables for tightness.

Make sure your clutch and sidestand neutral safety switches aren't the problem.

Unhook the fuel and vacuum line from the petcock. With a couple of lengths of hose, hook 1 to the fuel and 1 to the vacuum port. Put the fuel line in a container and the vacuum line in your mouth. Turn on the petcock, suck on the vacuum line and see how much, if any, it's flowing. It's not unheard of for gunk to build up in the petcock or have a sticky internal diaphram.

Well, I don't think its the electrical. It'll start easy enough and idle for 10 minutes. Though it is idling really very low on cold start (it's 70 degrees here and I didn't give much choke). Also, since it will idle I'm not suspicious of the clutch / side-stand switches.

I pulled the air filter and its not air. Checked the petcock, plenty of fuel flow with vacuum.

It still wants to cut out if I get close to 2000 rpm. Any other ideas?

I think there are two separate issues here. The first problem with the black smoke and fouled plug I would guess to be a needle/seat problem. Probably some junk was holding the needle off the seat and flooding the carb.

The second problem with the symptoms opposite of the first problem I would think is a slide diaphragm not seated properly or maybe even torn.

Good luck


I'm trying to think of things that would make it just die suddenly with no warning like it did, and then run like it is now, afterwards.

Has the Doohickey been replaced on this bike? A broken Doo or Doo spring could cause your symptoms, especially if it caused the engine to jump time.

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