On the road to Ushuaia and KLR650 is having carb issues...any suggestions?

Discussion in 'Thumpers' started by alison's wanderland, Nov 2, 2012.

  1. alison's wanderland

    alison's wanderland Been here awhile

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    I am now only about 10 days on the road (out of 6 months) and my KLR (gen1) has been giving me carb issues for the past week: at 4500rpm (+/- 500) the bike surges/bogs/hiccups when I am cruzing along on asphalt. It feels like the bike is starving for fuel, but runs fine at idle and lower rpm.

    Each day i have tried something new:
    - I changed the inline fuel filter
    - I removed the inline fuel filter thinking it was vapor lock (it's not)
    - I have tried running it on the reserve option on the petcock
    - I already have a .22 cent mod so I added another washer (a 27 peso mod) and it kind of worked (it bogged at 5500 rpm instead and the power loss was so great I couldn't pass trucks, so I ended up removing it)
    - I cleaned the slide thinking some crud got in the way, but nothing was found.

    - Next: I am about to look at the diaphragm for any inconsistencies.

    Any other suggestions?

    (and its not the fuel...I have been traveling with 2 other KLRs, pumping from the same tanks and they have not had any fuel issues.)
    #1
  2. XpressCS

    XpressCS Must. Have. Lumens..

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    Have you tried cleaning out your carb? Or checking for air leaks?
    #2
  3. bomber60015

    bomber60015 Anatomically Correct

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    next time it misbehaves, try opening the gast cap -- if it clears up toot sweet, you found the problem . . . . .
    #3
  4. XDragRacer

    XDragRacer Long timer

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    Diaphragm air leak a possisbility; hole/tear in fabric, or . . . seated/sealed incorrectly.

    Assume main jet is CLEAR.
    #4
  5. bess227

    bess227 Adventurer

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    doesn't take much of anything to get in that jet and make it clog up. had an S40 suzuki thumper that was notorious for that. simple bowl drain did wonders..

    good luck,certainly hope you find it's something really simple.
    #5
  6. Beezer

    Beezer Long timer

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    sounds like a diaphragm to me.... good until 4000 rpm. they can be patched with a small piece of bicycle tire patch until you get a new one. buy the Harly one for their CV40 ... it's half the price of a Kawi part (same part)
    #6
  7. Ranger Ron

    Ranger Ron Been here awhile

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    Don't overlook the petcock. A defective petcock (or vacuum leaks to it) can cause the same symptoms you describe.

    Good luck...

    Ron
    #7
  8. RandoCommando

    RandoCommando Wannabe

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    I was having the same problem.
    Turned out air was leaking into my petcock.
    I replaced the petcock and all was fine.
    #8
  9. Hektoglider

    Hektoglider One with Life

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    good thing to try. Its probably something simple. Verify your petcock= un hook fuel line from carb, un hook vacuum line from carb, apply vacuum to the smaller diameter vac line, and fuel should flow like horse piss, while your there, drain your float bowl with the small hex key. Refill the bowl, and drain it again, what the hell.

    Mine was acting the same way, and it was the vacuum line was leaking air, causing the diaphragm to not fully open, resulting in less than adequate fuel supply. Enough for low speed/idle, but high speed the bowl would run low.
    #9
  10. Adv Grifter

    Adv Grifter on the road o'dreams

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    Pulling the Carb out for inspection and cleaning would be my first move.
    You can try draining the float bowl ... always a good first move as water and crud does collect in the bowl.

    I'd do the same with your fuel tank. Pull petcock, drain and flush tank, clean petcock filter stems with toothbrush. Careful with all O rings and other rubber parts.

    Diaphragm could be the problem too. Inspect, making sure its not pinched or has a small hole. Unlikely, IMHO.

    Once inside the Carb, carefully check the Pilot Jet. It has several tiny orifices which can clog easily.

    After all jets are pulled out use high pressure Air and Flush well with Carb cleaner into orifices where jets seat into. Clean and re-assemble.

    If you can, get hold of a Carb kit and replace all rubber O rings and other rubber parts. Perhaps use a fuel additive once a month or so to chase out crud, debris, water and rust. Something like Sea Foam or whatever equivalent they have in Argentina.

    Good luck ... !y que le via muy bien!
    #10
  11. alison's wanderland

    alison's wanderland Been here awhile

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    That's worth a shot...I'll try that next...

    Thanks for outlining the how to...I'll try that tomorrow. Everything is closed on Sundays so I have a day to check things out.

    OK... lots of options. Have pulled the carb and wiped clean. The pilot jet is clean (did that just before I hit the road since it was giving me idle issues, but that problem is solved) did not blow out the main jet though. I have drained out the float bowl, but maybe worth doing again. Sounds like the petcock is worth giving a better inspection. And the diaphragm. There are no evident tears but I will look for pinholes.

    Thanks for all the replies! Gives me something to work with tomorrow.
    #11
  12. alison's wanderland

    alison's wanderland Been here awhile

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    Thanks for the advice. There is always a harley dealer close by.

    Worth a test...Thanks!

    Next on the list. thanks!
    #12
  13. alison's wanderland

    alison's wanderland Been here awhile

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    After having a fun day chasing an electrical issue (i.e. finding the wires that vibrated loose so my bike would start again)...I finally had a chance to dig into the carb situation.

    Looked at the diaphragm (and even with a second opinion) it looks in good shape. No rips, tears or pinholes. Carb is clean.

    Question about the petcock...mine is modified so it is gravity feed and not based on vacuum, how should I test if is good or not?

    Thanks!!
    #13
  14. Adv Grifter

    Adv Grifter on the road o'dreams

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    First thing is to simply pull fuel hose off Carb, turn Petcock to ON and see how she flows. Do it with fuel cap ON tight. Let it run a while (into container, obviously), see if it slows or stops after a few minutes. If it stops, open fuel cap. If fuel flows again then you know your fuel cap is not venting well enough. They do clog over time, moisture.

    Next up, I would drain tank (save gas) and flush it out. Unbolt Petcock, pull it out and clean the internal filters. Does it look like this? Clean it up, flush out.
    [​IMG]
    This from my DR650 after 40,000 miles without a clean.

    If the Carb is all good then perhaps somehow its an ignition issue? I hope not.
    #14