Anyone had this problem?

Discussion in 'Motorized Bicycle General Discussion' started by ADDICTED BICYCLES, Oct 4, 2009.

  1. ADDICTED BICYCLES

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    So I just went for a night ride, 21 km run. About half way, I hear this horrible grinding noise. I stop, clutch, idle, still there. I realized it was from inside the engine, and not the bike. I waited for the engine to cool, and then I removed the right side panel. When I looked at the gears, it seemed fine, until I noticed that the long slotted flat head screw holding the small sprocket on, was about to come off! The grinding was the screw itself, grinding into the panel! There is a small ground disc on my cover now, where the screw was grinding. So, I used an allen key to jam the gears, and tightened the screw as much as I possibly could. I replaced the cover, and started her up. It was fixed, got me all the way home again. :) Whew, That was a catastrophy narrowly averted! If I've learned anything about these engines, is you need to learn to listen to it. The engine will tell you when something is wrong, and when you detect a difference in it's performance, you should stop immediatly and inspect, don't run it to see if it will fix itself. lol, You may avoid a breakdown with a fast reaction time. :) So, has anyone ever had this happen? Why would it have come loose in the first place? Will it likely happen again? Thanks guys, later. :)
     
  2. BarelyAWake

    BarelyAWake New Member

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    entropy = everything's falling apart o_O

    No - I've not had that problem yet but I'm glad you mentioned it, it's another thing to look out for lol

    I just assume that my bike is always disassembling itself heh, I don't run about tightening stuff alla time but I do like to keep an eye on it. I suspect that you put a few miles on yer bike given you're also a commuter.

    Speaking of which, it's almost time for my Sunday distance cruse :D

    *dances*
     
  3. ADDICTED BICYCLES

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    Nice! :) That's why I love this forum. :) You have a problem, you fix it, you post it, and perhaps help out a fellow rider! Sweet. :)
     
  4. MikeJ

    MikeJ New Member

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    Hi Addicted -

    You asked, "So, has anyone ever had this happen? Why would it have come loose in the first place? Will it likely happen again?"

    Answer: YES! Twice now to me! And I am prepared for it to happen again a long way from home.

    IN MY CASE.... There seems to be a sequence of preceding events. When riding, I noticed a long stretch (maybe a couple of hours) of metallic "pinging" sound, as if the piston was smacking the cylinder head. Then I suddenly lost total power to the drive wheel, even though I could rev the engine (until I shut the engine down; then the engine would not turn over when attempting to start it).

    I took off the right cover, just like you. In both cases, the screw you speak of completely loosened itself and the woodruff key fell out of the shaft. The application of blue Loctite from the previous event did not hold; maybe it softened with heat over time. Without that woodruff key, the 20 tooth sprocket cannot turn, though the crankshaft does.

    With tools that I carry, I reassembled the sprocket along side the road. I was 55 miles from home at the time. The second time I reassembled, I put a dab of gear grease found in the gearbox on the threads. It is too early to tell if that will help. Upon reassembly, that "pinging" sound did not reoccur.

    The woodruff key (the original) is beat up and severely deformed. I need to order a couple more, and maybe a new 20 tooth gear as a backup. I replaced the screw once just because the original one was beat up from the factory.

    Expect this screw loosening to happen again. Loctite is not the final answer. Maybe check before each ride for a while. Periodic inspection and having tools available to fix along side the road is in your best interest. Hint: take a clean cloth with you. Spread it on the ground under the engine before you open the gearcase. If you lose that woodruff key in the grass and don't have a spare, you will be peddling. In my case, if I have to call ladyfriend for help, I owe her two expensive dinners. Two dinners will buy a lot of support parts!

    MikeJ
    760 miles to date. 65 miles after the second loose screw event.
     
    #4 MikeJ, Oct 4, 2009
    Last edited: Oct 4, 2009
  5. Norman

    Norman LORD VADER Moderator
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    If you use a hand impact wrench on that screw it won't come loose. You can get the tool at sears,harbor freight etc. cost about $10.00. I show how to use it in my posts.
     
  6. Kevlarr

    Kevlarr New Member

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    I wish I knew where to get the washers that are on my moped hub's sprocket. They're a flat washer but on the face it looks like there's the impression of a star washer in them. I have a heck of a time getting the nuts and bolts loose even when they're not fully torqued.

    If I could find where to get these washers I'd use them everywhere on my bike and they'd probably work perfectly in this application.
     
  7. Norman

    Norman LORD VADER Moderator
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    most good hardware stores sell the toothed washers some go kart shops sell them and the nuts
    with the built in teeth on the nuts. Might even try lowes or home depot some have draws that have the (special) parts in them.
     
  8. mick29

    mick29 Member

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    I had a strange squeeking coming from my brand new motor i started it up for the firt time it was great went for a ride all ok second ride it started squeeking and got lowder and lowder it ended up beening a bearing the one on the shaft that runs the front sprocket i pulled it all apart all i did was give it a spray with CRC i have done over 200kms since not a squeek thanks mick29
     
  9. ADDICTED BICYCLES

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    well, I've ridden it hard since the screw came loose, so far so good. I guess for everyone's future referance, check the screw holding your little sprocket on the inside right of your engine. Not sure what this part is called, but it would be the end of your ride if it lets go. I was sooooo close! One more good twist and I think I would've had a catastrophy. Be safe out there guys! Keep em rubber side down!
     

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