Stuck Drive Roller...Help!

Discussion in 'Friction Drive' started by blankbox7, Jun 20, 2010.

  1. blankbox7

    blankbox7 Member

    Recently I installed a friction drive 48cc 2-stroke kit on my 20" mountain bike. I had to modify the rear mounts, but assembly was easy.

    When I try to rotate the drive roller, it doesnt spin freely: When I went for a ride, it would only start to move at full throttle and with the bike already moving.

    It is aligned with the tire, I dont see how I could disassemble it w/out taking the engine off, and even then I dont know what to look for. any ideas?

    Attached Files:

  2. moondog

    moondog Member

    Take it all apart and measure everything. The channel not being square or the holes drilled in the wrong places are common problems on these made in China friction drive kits.

    The crank and the roller shaft must be in alignment and square with the channel.

    P.S. I would get one of these.
    Last edited: Jun 21, 2010
  3. moondog

    moondog Member

    Also, is the bolt in the rear of the channel making the channel out of square ?
  4. blankbox7

    blankbox7 Member

    It was at first, but then I added spacers on the inside to prevent the channel from flexing when tightened. I have yet to disassemble and take measures, but thanks for the advice!
  5. blankbox7

    blankbox7 Member

    I began disassembling, and then I ran into a problem: The spindle assembly is held together by 1 bolt, and I need a way to hold the spindle from spinning. (this would be SO easy if I had a pipe wrench...)

    If anybody knows how I could do this, please let me know!

    Attached Files:

  6. blankbox7

    blankbox7 Member

    I finally got the nut off, and then simply unscrewed the clutch drum off of the shaft. I measered the channel in 4 different places, each time coming out the same and at a right angle. The holes drilled for the bearings are also acurate.

    I couldnt pull the shaft out from the bearings (after I took out the spindle screws) I am clueless as to what could be creating so much drag on the shaft :(

    If ANYONE knows what this could be, please let me know!

    Attached Files:

  7. 5-7HEAVEN

    5-7HEAVEN Guest

    Does it?

    With everything but the engine bolted on, does the drive roller spin freely? If not, don't bolt the engine on yet. Are the channel bearings 1/2" or 5/8" inside diameter? I noticed sleeves around the drive bolt. What is the bore of the drive roller? How is it fastened to the drive bolt? Setscrews? If the drive bolt is 1/2", you might want to replace the drive bolt with a 1/2" shaft.

    How are your channel bearings?Do you have spare channel bearings you can install?

    If all spins nicely, install the engine. Does the engine spin freely without scraping the clutch drum? Can you spin the drive roller freely? If not, the engine mounting bolts might be too lopng and binding with the flywheel. It also could be that the clutch drum could be bottoming out in the engine bellhousing. Hardly unlikely, though, because you'd hear the loudest screeching sounds of bare metal.

    Keep us posted.
  8. 5-7HEAVEN

    5-7HEAVEN Guest

    Where did you buy the friction drive kit? Did you try contacting the company?

    Maybe you DO need a pipe wrench. They're cheap enough. The setscrews probably gouged the shaft, which makes it harder to spin the roller off the shaft.
  9. blankbox7

    blankbox7 Member

    The drive roller does not spin freely when the engine is not attached. The drive roller is attached to the drive bolt by setscrews. I would change out the bearings, but I cant pull the drive bolt out of place (with the set screws taken out) what would cause this?

    The engine is not the source of the friction, and the spindle isnt rubbing against anything, so I'm guessing its the bearings, but I need to take out the drive bolt to measure it.
  10. 5-7HEAVEN

    5-7HEAVEN Guest

    Hey, now we're getting somewhere!:detective:

    The setscrews probably have left grooves on the drive bolt. That's why the spindle won't slip freely on the drive bolt. However, that doesn't explain why the drive bolt does not spin freely in the bearings.

    Firstly, shoot some penetrating oil between spindle and drive bolt. Use the pipewrench/channel locks/visegrip wrench to work the spindle around and round. If you're lucky enough to loosen the spindle, reinstall and tighten the setscrews. Shoot some penetrating oil in the bearings and onto the drive bolt where it passes thru the bearings. Then use the pipewrench/channel locks/visegrip wrench to work the spindle around and round. If you're lucky, everything loosened up. HOWEVER, I would advise you to replace the bearings, no matter what, even if it wasn't the problem to begin with.

    Check to make sure that the drive bolt is not bent.

    That is one fancy expensive clutch drum spacer, especially when compared to BMP's four aluminum spacers between engine and friction housing.

    Good luck and let us know how you progress.
  11. Esteban

    Esteban Active Member

    Good advice above.
    Looking down on your very last pix, from the underside of the mount,,, it looks like the drive roller is at a slight angle ! This would mean that the opposing mounting holes for the drive roller are NOT aligned. This could cause binding & would be a manufacturer's defect.
  12. 5-7HEAVEN

    5-7HEAVEN Guest

    How long have you had this friction drive? Did you buy it new or used?

    As an absolute last resort, you could swap in the entire BMP or Staton driveline components to fix the problem. Motor mount holes look bigger than BMP/Staton, though.

    I'm not an engineer, but the whole idea of a drive BOLT instead of an axle sounds cheesy. That drive bolt does not look to be a perfect fit for the bearings. Is that a sleeve I see between the drive bolt and the bearing's center?:whistling: