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.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Similar Content

    • By Josh Munn
      Hi guys i recently bought a klr600 thats was running but had issues the guy i bought it off had fitted a manual timing chain adjuster but it had jumped a tooth and would hardly run i fixed that but it seems like the timing is retarded any one had this issue not sure what it uses as a pick up or if it has an auto advance. Cheers 
      I also own a 81 xl185s, 81 xr250, and a 83 xr350. Cheers
    • By CantleyCustoms
      Hello guys,New to the forum.
      Quick question,I have a 1994 klx650c i recently purchased and am in the process of upgrading it.
      Have a trial tech vapor speedo ready to fit,however just wondering about the stock instrument gauges etc.
      Is it literally a case of unplugging the old dash and fitting the Vapor? Is the Dash used to complete the stock wiring circuit? e.g-if i unplug it and leave it unplugged is it going to effect the running of the bike? What about the dash lights,how would i go about wiring these up?
      electrics really isn't my strong point,got the basics covered but way too complicated for me.
      any help greatly appreciated,any more info you need please feel free to ask.
    • By rodrigonehme
      Hello, This is my first post and I'm new to TT.  I recently acquired a 2008 KLR650 (which by the way I absolutely love) and I'm working on adjusting my valves, I already measured its clearances and found this helpful online calculator: however I'm unsure of what the shim factory setting size is and it is essential to get the right shims. Does anybody know what the factory settings are?
      Thank you!
    • By RT_Chris448
      Recently we did a project bike with Dirt Bike Magazine's KLR650 and we were pretty excited about the results.  Check out the article on this fun project here:
    • By DougBurgoyne
      Hey guys,  
      A super duper THANKS for all the help, laughs, and fun I've had here, and the bike I put together based on advice and lots and lots of reading material you've provided on what is the best vehicle forum I've ever encountered (been on many over the years). . 
      Just when my bike was absolutely the bike I wanted it to be, my riding buddy (who is my father in law) bounced of his DRZ well up 4610 here in Oregon and broke his leg, and good. Tib/fib  job requiring rods, screws, plates, and a kitchen sink to put back together. If it wasn't for the MX boots I got him, and "forced" him to wear....there would have been all sorts of nastiness sticking out of the skin. No doubt about it, as both lower bones broke at sharp angles making spears inside his leg. As it was, everything was contained. He is going to be down for quite some time. I bought my drz to ride with him initially as he had a KLR650 and had an interest in backroad and moderate trail riding. On our first trip out (Brown's camp easy/mod trails) after about 10 times picking up his KLR with over-inflated 50/50 tires (mine stayed on 2 wheels all day long) he said "I need a bike like yours". Within a week he had his DRZ too! Then over the fall and winter we did all the mods and fixes to get them ready for this spring/summer.  It was kind of a miracle I even convinced my wife to let me get a dual sport bike. I'm 50 now, and have a degenerative vision disease called RP. Basically, I'm missing quite a bit of my vision field, but have decent vision straight ahead (unlike macular degeneration). I'm not in denial that good/full  vision is important for safe motorcycle riding on the street...and the reason I'm a 90/10 dirt/street guy. My argument was that we won't get hurt just poking around the woods, old man style, with occasional pavement work to connect trails (thus the need for dual sport over dirt bike).  Well, my father in law shot that theory down, but good!  He has dealt with so much pain over the last month, and met several dual sport riders in for riding injuries (some that make his look like a kid's day camp) that he decided he is out of the game. Unfortunately for me, that means I'm out of the game too. My wife is so worried I'm going to get injured badly, that it's not worth the fight. I don't want her and my daughter stressed and worried every time I go riding. My father in law was doing great on the roads and trails we've been riding. And just loved riding the DRZ. But he's 70 and looking at Jeep Wranglers with lift/tires for his forest adventures going forward. Not a bad call imo.  So...I've sold 2 DRZ's and a KLR in about 1 week (here in Portland OR, I could have sold 4 more DRZ's in the same time if I had them!).  His 1100 Honda shadow cruiser is on C.L. now as he is cleaning out the stable completely. Sad, sad day. It's only been a month since our last ride and I'm already missing the dirt big time. Even sold my daughters doodle bug. Oh well, life goes on. 
      Take care guys, ride safe (inside your skill level), gear up...and have some fun for me!!