Engine keeps flooding after short amount of cranking {SOLVED}

Discussion in 'Thumpers' started by Kino, May 30, 2021.

  1. Kino

    Kino Adventurer

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    did a rebuild on a klr 650 and am now trying to start it.
    The engine cranks over when i press the starter and is also getting spark and compression.

    At first it fired up for several seconds but immediately died, after a few more attempts it started to leak fuel from the header (which isnt tightened yet with the clamp). I have tried several more times without using the choke and it floods everytime. I adjusted the pilot jet to 1 and 3/8 turns out and it has the same issue. I then took the carb off and inspected every jet and hole and used compressed air to clean it once more. After putting it back in the engine floods again even after only 15 seconds of cranking.

    Some things are still on my mind that i'm trying to eliminate.


    Choke:
    The choke lever only stays to the right side, it will never stay on the left, the choke cable looks old but doesnt seem broken. I am still sceptical of the choke and will try to install an enricher without a cable.


    Carb:
    At the time of restoration of the carb i didnt use carb rebuild kits. I am now planning on taking the carb off once again and doing a complete rebuild with new parts. I also saw the diaphragm is damaged and will replace it too.


    Manual petcock:
    I have a new manual petcock installed on my gas tank and it works fine, i'm just mentioning in case this could case an overflow of fuel compared to the stock vacuum petcock.

    The spark plug is new, but perhaps cleaning it after being flooded 10 times is a good idea.

    I am pretty sure the carb is at fault but i dont know yet where exactly. I hope rebuilding it properly will fix my issue

    for now i am really curious what you are thinking, what part is failing and why is my engine being flooded fast and consistently ?

    Thanks
    #1
  2. Grinnin

    Grinnin Forever N00b Supporter

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    You have a leaky float valve in your carb.
    #2
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  3. Kino

    Kino Adventurer

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    Thanks I will put a new one in.
    (for the record: i checked the float clearance and it's good)
    #3
  4. Zuber

    Zuber Zoob

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    Yeah, leaky float needle. Also, since you'll be right there... Try lowering the float just 1/2 mm below specs. It almost always makes these engines run cleaner with better mileage.
    #4
  5. Beezer

    Beezer Long timer Supporter

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    but the KLR runs lean already unless you do the 22 cent mod (don't bother to drill the slide).

    and yes, I agree... needle is not sealing. cranking the engine should not have any effect one way or another if you have a manual fuel valve. btw, you did plug the vacuum line right?

    and my favorite bitch about the KLR... they need more fork oil than the book says. pull the springs and collapse the forks. fill until oil is 170mm from the top of the tube. thats a starting point. more oil = less dive and more stability
    #5
  6. Kino

    Kino Adventurer

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    I have stiffer springs and good oil level in there , will put some air pressure on the forks if they should still feel too soft.

    and I just rebuild my carb again with a new float needle, hope my klr starts and runs smoothly now
    #6
  7. Kino

    Kino Adventurer

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    I put the new float valve in, after about 30-45 seconds of cranking (not using the choke, didnt open throttle) fuel started spilling out of the header. I left the muffler off to spot the flooding faster.

    Unlike before, now there is also fuel dripping out of the overflow hole.

    I am guessing either i didnt install the float valve correctly or the float itself is perforated and sinks. Something is still causing fuel to gush into my cylinder.

    Does the float valve have some sort of gasket i'm not aware of ? Does it need to be installed in such away that it seals ? i just placed it in there without pressing on it.
    Before installing i used compressed air into the float valve hole to make sure there wasnt any stuff in it

    What do you think?
    #7
  8. Kino

    Kino Adventurer

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    The issue has been solved, i added a manual petcock during my restoration and didnt remember how the fuel hoses had to go on the carb, the fuel line was installed on the vacuum connector and the real fuel inlet wasnt utilized.

    As soon as a realized this i plugged the vacuum hose and put the fuel line on the right place. The engine now runs smoothly and starts on the button.

    Thank god i'm not gonna have to pull the carb off anymore :D
    #8
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  9. Beezer

    Beezer Long timer Supporter

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    oh yeah.... and if you get the chance, remove the screws that hold the manifold to the cylinder. replace them with bolts. the ones they use on the case with the smaller 8mm heads are best. you can also use Allen heads but have to cut down a wrench to fit in the tight space. then you can remove/install the carb and manifold together as one piece. the manifold is flat with an O ring & slides right in... way easier than fighting 2 gobs of rubber. glad you got 'er fixed
    #9
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  10. Kino

    Kino Adventurer

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    Thanks beezer that's a golden tip , i already have a bunch of the 8mm engine case bolts lying around from my old engine (perhaps you remember i swapped in a new 2012 block during the restoration).

    I did a few rides today and it went great, the new engine has 150 miles on it and it's hard to be patient and ride below 4000rpm :(
    I wanna unleash the beast !

    Will be doing a thread showcasing my glorious klr 650 soon, it turned out real beauty !
    #10
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  11. Beezer

    Beezer Long timer Supporter

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    don't worry about the RPMs or the miles. the most successful break in's I hade were to drive it normal. use engine braking, vary the rpms, climb some hills... work it a bit harder after each heat cycle. I've done the MotoMan break in too (full on from the start)

    personally, I think that RPM limitation is a lawyer thing. 4000rpm is 55mph with stock gearing. might be a coincidence....
    #11
  12. Kino

    Kino Adventurer

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    yeah you're right, i've read the motoman article too and it makes sense. I'm having a blast out here !
    #12