klr 650 compression

Discussion in 'Thumpers' started by side-wayz, Aug 2, 2013.

  1. side-wayz

    side-wayz See Ya in the twisties

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    Klr died on the way to work this morning, getting fuel and spark. I tried doing a compression test and got 35 psi but I read there is something where the valves stay cracked open for an easy start??? Can anyone tell me how I am supposed to check the compression?
    #1
  2. Full Power

    Full Power Long timer

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    KLR is pretty slow, are you SURE it's actually dead ?
    .
    .
    When you say " It has Fuel and Spark" do you mean In the combustion chamber.... or do you mean fuel IN THE TANK, and SPARK at the coil wire ?
    It is possible that the vacuum hose to the fuel petcock has fallen off or cracked.... also a lesser but possible chance that the spark plug has failed.
    .
    . Normal cranking compression is listed in CLYMER as 77 to 124 PSI.
    You might get out the feeler gauges, make sure there is some valve clearance under all four cam lobes.
    #2
  3. Lomez

    Lomez Yea...Sunday too

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    not possible to check compression on KLR....or on many modern bikes for that matter. One exhaust valve cracks open when cranking. Leak-down can be done....if you have the time and tools.

    How do you know you're getting fuel to the combustion chamber? I'd be looking at the primary jet if you have spark.
    #3
  4. CycleDoc59

    CycleDoc59 Wrench Rider

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    Unless something drastic happens, compression
    does not "stop" while you are riding. The usual symptom
    of low compression is increased difficulty in starting...

    If low compression is suspected, the first thing to check
    is the valves; to be sure they are properly adjusted and
    sealing when closed. (sealing checked by leak-down test)

    The automatic compression release prevents normal
    compression checks. And if the valve cover is removed
    and the compression release deactivated, the starter
    can't usually spin the engine against full compression...

    If the bike simply stopped while being ridden, the problem
    is most likely either (1st) fuel delivery or (2nd) ignition related....
    #4
  5. the_gr8t_waldo

    the_gr8t_waldo Long timer

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    drain off fuel from the bottom of the bowl..if you get nothing, you got no fuel! and attention should shift to the vacume enabled fuel petcock.
    #5
  6. side-wayz

    side-wayz See Ya in the twisties

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    haha, hey it gets up to 100 mph at about 7000 rpms.

    It has fuel and spark in the combustion chamber. I'm gonna dig into it some more and see what I can figure out.
    #6
  7. side-wayz

    side-wayz See Ya in the twisties

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    I took the spark plug out and was wet and smelt like fuel. I would think it would at least try to fire.
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  8. side-wayz

    side-wayz See Ya in the twisties

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    yup, got fuel in the carb.
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  9. side-wayz

    side-wayz See Ya in the twisties

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    Its been starting fine and running good everyday and just acted like it ran out of gas. the engine turns over, just won't fire up. I'll have to see how to start testing ignition.
    #9
  10. side-wayz

    side-wayz See Ya in the twisties

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    Thanks for the ideas everybody, I'm gonna do a little more research and hopefully something makes sense to me.
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  11. D.T.

    D.T. Difficult but useful

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    I'd like to know some of the tricks of compression testing with a ACR myself..:ear Service manuals are no help. I suppose you could use a zip tie.

    My SV had a centrifugal that came off the bucket when the cam came up to speed.
    #11
  12. side-wayz

    side-wayz See Ya in the twisties

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    zip ties hold the rest of my bike together, why not?


    I'm hoping a leak down test will work, but I have to figure out how to do that first.
    #12
  13. side-wayz

    side-wayz See Ya in the twisties

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    I'm thinking about taking the spring off that holds the exhaust valve open for the KACR. bad idea or good idea? seems like it'd work but a lot of work just for a compression test.
    #13
  14. side-wayz

    side-wayz See Ya in the twisties

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    sounds like if I took the spring off that holds the exhaust valve open while starting, I could get an accurate compression reading. Mines only reading 35 psi without disableing the kacr.
    #14
  15. D.T.

    D.T. Difficult but useful

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    Cheapo leak down would be take the exhaust pipe off and intake boot off the head. Then put air down the spark plug hole at TDC. Then see where it leaks. Piston would be out the crank breather.


    I'm not a KLR owner, just bored and want to participate. :)
    #15
  16. *Gmoney*

    *Gmoney* Long timer

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    After finding top dead center the same as a Valve adj,
    a leak down test would be simple.
    I do not understand how a leak down test is difficult.
    I think they are saying, its to much work, sell it to me,
    the old saying, its all junk, unless I own it.
    Just ignore those 2 plugs on the left side that allow access to top dead
    center,
    and a way to keep it from turning
    while under pressure from a leak down test.
    Just sell your junk on Hollywood Boulevard
    like most American males.
    #16
  17. side-wayz

    side-wayz See Ya in the twisties

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    just held the throttle wide open and cranked for a while and it started but I had to keep giving it throttle or it died. I notice fuel coming out the bottom of the bike from I guess an overflow tube or a vent tube.
    #17
  18. *Gmoney*

    *Gmoney* Long timer

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    Just foreign material in the needle and seat, float level to high.
    repair carb.

    Don't mind me every-time my KLR carb screws up
    I start calling it junk.
    #18
  19. k-moe

    k-moe Long timer

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    Yep...too much fuel. Check your oil...the float needle is probably not seating, and thereby allowing excess fuel to get into the combustion chamber (and then into the oil).
    #19
  20. *Gmoney*

    *Gmoney* Long timer

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    Moe is right you also have fuel mixed with oil time to change that also,
    or you will be doing leak down tests.
    :clap
    #20