Clutch slipping clutch?

Discussion in 'Transmission / Drivetrain' started by pokerhelper, Sep 26, 2010.

  1. pokerhelper

    pokerhelper New Member

    Admin, I reposted this here, this should me more appropo section sorry, ty :)
    Hi everyone, I wondered if anyone knows if this is the cause of my problem?
    I went to the store, and while I had my "80" cc chinese 2 stroke motorbike parked outside, some kid was playing with the throttle... (the security guard told me he told him to leave the bike alone) He opened the throttle all the the way up, and when I came out there was a puddle of gas/oil mixture on the ground, its like the float bowl was overflowing and gas was pouring out of the carburetor. (that taught me to close the fuel petcock next time I park it anywhere)
    The gas collected on the area below the clutch arm...
    Ever since then, the clutch slips so much I cant even get the bike started...
    when that brat opened the throttle, and the oil gas was leaking out, could it have worked its way through that crack where the metal meets on the engine, and got on the clutch pad?
    I dont want to overadjust the clutch before I know (I did search for similar)
    I can remove the spark plug, and then it will turn over without having to fight the compression.
    It would start perfectly before, this is the only X variable that I can think of that could have caused this.
    Does this sound plausible to those who know more than I do, and is there a fix? (Oh, why did Mike go to Windsor when I need him, must have been a Wiz in or something, lol)
    If you can help, I would appreciate it, thanks everyone :)

  2. motorpsycho

    motorpsycho Active Member

    even if he twisted the throttle 100 times, that would not cause the carb. to flood over.
    these carbs rely on vaccuum to suck the gas into the engine. so, gas will should only come out of the carb (into the engine) when the engine is running. these carbs do not have accelerator pumps like car carbs. do. an accelerator pump "squirts" gas into the engine and that's why when you used to pump the gas pedle on your dads old carbureted car, you would flood the engine. you were allowing the carb to squirt gas into the engine every time you pumped the gas pedal until the float bowl ran empty.
    the puddle of gas you saw was more than likey from you leaving the petcock open . these carbs. are gravity feed, and the carb. will seep or leak gas out of the overflow if you leave the petcock open. on top of that, the float set up in these nt carbs is not the best set up. the float can jostle sideways from vibration, which will not allow the needle & seat to close all the way...which results in the carb. flooding over while sitting still, engine not running. another thing is that if your carb, has a primer button, sometimes they can stick. the primer button pushes the float down every time you push it. so if the primer button was stick in the down position, the float would have been pushed down, and even if the float bowl was full of gas, the needle & seat would be open "asking" for more gas. if this is the case, then the float would never be able to close because the primer button was holding it open...and gas would just flow into the carb, and out the overflow tube because you left the petcock open.
    so, the "brat" probably had nothing to do with the carb. flooding over.
    it was by your own ignorance that you did not close the petcock.
    as for the gas getting into the clutch area, i guess it's possible, but the clutch cover has a gasket on it, which seals i doubt that gas got into the clutch.
    if gas and oil had gotten into the clutch , the gas would eveaporate and the oil would leave a little residue on the clutch pads. but, the residue more than likey would wear off after trying to start the engine a few times.
    if you have never seen the clutch in one of these h.t. engines, you are in for a big surprise. the clutch pads are just peices of rubber.the heat alone can cause the clutch to slip and "polish" the pads, which makes them very slick and smooth.
    you need friction (or a rough surface) for the clutch to engage and if the pads are smooth and shiney, more than likely the clutch will slip.
    just like the brakes on your car. if you smooth and polish the rotors and pads, you will not have very good brakes.
    Last edited: Sep 26, 2010
  3. Al.Fisherman

    Al.Fisherman Active Member

    Nice reply.... It is IMPOSSIBLE for gas and oil to get into your clutch by the way you describe. Look at the clutch housing, it's cast into the right engine side. In order for a fuel mixture to seep into the clutch the engine would have to be submerged in gas/oil above the engine valley. Ant liquid will run out of the valley before entering the clutch assembly.
  4. HeadSmess

    HeadSmess Well-Known Member

    mmm, tis strange.

    but of course, i can always see certain other aspects.

    ok. so the carb flooded. can only be caused by faulty float needle and or seat. or incorrect height of float.

    but maybe having the throttle closed with the jet needle almost completely obscuring the main jet was enough to hide such a problem?

    so then having the throttle WO, allowed the fuel to trickle from the main jet? especially if the fuel height is only a few mm too high...

    it does. thats the lowest point for fuel to emerge in case of overflow. at least on my carb it is.

    so it could have maybe slightly been the brats fault...but whos the brat in this story? :lol:

    but then the clutch slipping....hmmm... yep, i agree, ive never had an issue with copious amounts of fuel in that "valley"...bad bit of design there btw...


    my carb flooded just the other day. its getting tired. :(

    it then filled the crankcase... lucky the piston stopped at tdc huh? i didnt know at the time...

    i then jumped on to start it and stopped short when it hydralic locked on me... the gorilla in me forced it over anyways, and i got a nice squirt of fuel from the head gasket :eek: i think i may have damaged something finally :lol:

    maybe fuel has escaped via a faulty gasket from crankcase and into clutch? or crank seal even... just a theory. just a theory.

    personally, id blame the kid for about five minutes then get home, find the problem and forget about it :)

    in fact, on re reading...maybe the fuel is still in the crankcase? and the clutch was on the verge of slipping and now with the hydralic lock.... another theory :)

    but all based on experiences :)
    Last edited: Sep 27, 2010
  5. motorpsycho

    motorpsycho Active Member

    nope because the jet needle does not seal the main jet. even if the needle is all the way down, there would still be enough room for fuel to come out of the main jet and flood the carb.
    when you set your idle, you are raising the slide, which raises the needle, which lifts it up away from the main jet. so with the idle set right, the needle is away from the main jet anyway.
    so it would have flooded over with the throttle closed no matter what.
    i still think that it's a needle and seat / float issue, and the fact that he left the petcock open.
    Last edited: Sep 27, 2010
  6. Al.Fisherman

    Al.Fisherman Active Member

    If fuel got into the crankcase the float needs to be looked at. You might have a saturated or faulty float/needle/seat/float tab. Thus not closing off the fuel supply. There is only so much fuel that the bowl can hold before the float/needle closes the supply off (seat). With a good float system you could work the throttle from off to WOT all day long and no flooding should occur. Make sure you check the primer plunger and its not touching the float until you press it down.
  7. HeadSmess

    HeadSmess Well-Known Member

    actually, ....i shut my mouth :lol:
    Last edited: Sep 28, 2010