Back wheel won't free wheel (clutch wont disengage)

Discussion in 'General Questions' started by ayo2001, May 7, 2016.

  1. ayo2001

    ayo2001 Member

    Ok I apologize for my ignorance in advance but like the question says in the title I can't get my back wheel to Freewheel. I hold in the clutch but it still doesn't freewheel, keep in mind though that I just installed a brand new engine on the bike so that may be my problem. Do new engines have trouble getting started ? is this a common problem ,do I have to lube or grease up one of the sprocket wheels,is something stuck? The engine is a 80cc btw, please help guys
     

  2. FurryOnTheInside

    FurryOnTheInside Active Member

    Disconnect clutch cable.
    Remove sprocket cover.
    Visually inspect the bucking bar.. That's the little bar that you can pull out from the centre of the drive sprocket. It should protrude from the sprocket shaft about 6mm or so so the clutch actuator cam can push against it. If it doesn't protrude then they forgot to put the ball bearing under it at the factory. This is a common problem. You should be able to pull out the bucking bar and see it in there with the aid of a flashlight, all shiny and silver and covered in thick grease.
    If it isnt there, there bucking bar doesnt protrude. You might need a magnet to pull it out. Look inside.. Just darkness and no shiny greasy ball? Then you need a common ball bearing same diameter as the bucking bar.. 6mm I think. Grease it up and drop it in, then replace the bucking bar.
     
    Last edited: May 7, 2016
  3. ayo2001

    ayo2001 Member


    OK I had a look and everthing looks fine, Mabey the chain is hitting the clutch cover or something?
     

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  4. FurryOnTheInside

    FurryOnTheInside Active Member

    Can you wheel the bike forward? I thought it was just not freewheeling.
    The drive sprocket can have burrs that should be filed off.. But that doesn't stop the chain seating or the clutch disengaging..
    If you can turn the wheel and chain but it always turns the engine, then check your clutch cable is properly seated in adjusters. That's all I can think of. The clutch arm is moving when you pull the lever though?
     
  5. Timbone

    Timbone Active Member

    Very often, a new HT motor has a sticky clutch. Very common. Remove the clutch cover on the pedal drive side and tap the clutch drum a few times with a hammer. As you activate the clutch arm, you should see the clutch drum move out about 1/8".

    That's what makes the rear wheel freewheel. The drum is lifted off the clutch pads.

    For reference: to get more bite in the clutch pads, tighten the flower nut. For less grab, loosen the flower nut.

    While you are in there, you may want to add a bit of grease to the small drive wheel...
     
  6. FurryOnTheInside

    FurryOnTheInside Active Member

    Please show me the top view of your engine (assembled).
     
  7. FurryOnTheInside

    FurryOnTheInside Active Member

    If the lever does move all the way but the clutch doesn't open, the problem must be in the cable, cam, or bar. (?)
     
  8. ayo2001

    ayo2001 Member

    Here it is
     

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  9. crassius

    crassius Well-Known Member

    first, take out the spark plug to see if motor CAN turn, if so, investigate clutch
     
  10. ayo2001

    ayo2001 Member

    Ok so I took out the spark plug, and now it moves when I pull the clutch in, it's still a bit a tough though probably because the engine is brand new.
     
  11. FurryOnTheInside

    FurryOnTheInside Active Member

    If the wheel still turns the engine all the time: Search "flower' in the search function at the top of the page and read read read until it all becomes semi clear. Be careful removing the little brass screw as it strips easily.
    Let us know what you did and how it went. :)
     
  12. ayo2001

    ayo2001 Member

    OK I'll keep you guys updated, my only problem now is that my chain is close to hitting one of the engine mounts, do you guys think I have my engine mounted incorrectly? (See pic for example )
     

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  13. FurryOnTheInside

    FurryOnTheInside Active Member

    No it looks normal and your chain is out to the left of that, I'm sure that's fine. I'm waiting to hear about your missing spring or something. I think that is the "pressing" issue. See what I did there? I'm a punny guy..
    I think it's time for a new clutch cable, and wth happened to your pedals? :eek:
    Anyway.. Clutch adjustment with flower nut. Supposed to be a spring under the plate. Carefullll with the brass screw. You tried tapping it with a plastic mallet like Timbone said?
     
  14. ayo2001

    ayo2001 Member

    Yeah the pedals were cheap and one just completely broke off, but anyway the clutch side is what I'm supposed to be hitting with a rubber hammer? (See picture) is that going to loosen up anything? Oh and I checked under the clutch plate, there was a spring in there so I'm good there.
     

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    Last edited: May 7, 2016
  15. FurryOnTheInside

    FurryOnTheInside Active Member

    Oh well, as long as youre not riding it like that, lol. If I had a penny for all the times I've had a pedal or a stunt peg hit my head/back a moment after crashing a bike, lol.
    I dont know what the mallet does, I never needed it! Sorry. Can't hurt though? The engine sat on a shelf/truck/ship/warehouse/shelf for months/years before you got it so things like pads and plate might have stuck together? I guess.
    Yeah you can feel that light spring when you press on the clutch plate with your hand while it is held open by the locked lever, while you were taking out the little tiny screw and messing with the flower nut, unscrewing it up the thread on the clutch mandrel to the very top to try to get more seperation. But you've had the plate right the way off? The flower nut can be right on the very top of the mandrel. Well my flower nut is anyway. Reading another thread now that's not really normal. Have to check that out... The plate on mine does not sit level and even when clutch is opened. Don't know why. Yours I can see the light hitting the top of the mandrel so the nut is definitely on further than mine.. But then it is a different engine.
     
    Last edited: May 7, 2016
  16. crassius

    crassius Well-Known Member

    hard to tell from pic, but one should always try to get rear mount studs as close to perpendicular to frame as possible since that is where all the force is - I also always use a piece of PVC pipe there to keep frame from being sawn in two
     
  17. ayo2001

    ayo2001 Member

    Here's my only problem now, I tried to shorten my chain to length so I wouldn't have to use that stupid cheap Chinese chain tensioner that came with it but in doing so I may have shorten it too much ,now when I try to feed the chain through the drive sprocket and the Hub sprocket on the back Wheel it seems a tad bit too short. The picture you see attached is the small piece of chain that I took off and when I add it to the chain it's long enough, but I'm trying to use what I have so I don't have to use the chain tensioner. Any suggestions?
     

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  18. FurryOnTheInside

    FurryOnTheInside Active Member

    File any burrs from the sprockets that may impede proper seating of the chain on the teeth. Check that the chain rollers are properly contacting the troughs between teeth and that the chain is not being supported by the "shoulder" / bulge of the sprocket instead. Compare the tooth profile (looking from the side of the bike) to those you see on bicycle sprockets. They may appear very square at the top/tip of the teeth. File this square edge. It would wear off anyway. This may help your chain to engage smoothly and feel less tight.
    So is your clutch disengaging now? Was it just stuck like it's been sitting on a shelf til the grease dried out? What worked to free it up? Anyone doing a search for the problem will find this thread now it contains those words so it would be good to say what worked for you.
     
  19. ayo2001

    ayo2001 Member

    Well when I removed the spark plug that's what really got it moving in the first place, I guess the compression really had it stuck but anyway I tapped it with a rubber hammer on the clutch side and that helped a little bit too now it's moving smoother but I'm going to put a little grease on it to make sure it doesn't have any problems there or anything and I'll also try to file some of the sprockets down so I'll keep you informed, I just need to get my chain on so I can test it.
     
  20. crassius

    crassius Well-Known Member

    you could put a 1/2link in the chain, but I always use the standard tensioner

    new chain will stretch about 1/2 inch during first week or so

    putting an extra piece of PVC in rear mount will take more slack out of chain
     
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