chain/sprocket/wheel problems

Discussion in 'Frame Mounted Engines' started by johnny q, Oct 13, 2008.

  1. johnny q

    johnny q New Member

    hi guys - I was fooling around with my bike today, trying to get it going. Last time I tried, I wedged the chain between the engine and the engine sprocket.

    Anyway, in the last little while, I have spent a bit of time looking at and working with the drive chain. I shortened the drive chain so it would fit without using a tensioner. That's a good thing, but the chain is still coming off when I try to start the engine. I have noticed a few other things that are preventing me from going for a ride. They are :

    rear wheel is warped - My rear wheel twisted up after I added the sprocket to it. I noticed this the day after I attached the sprocket to the wheel, but I figured I might as well try and see if it would work as is. It looks like the rear wheel has about 1" of wobble when I spin it, and the rear sprocket itself has about 1/4" of wobble to it. Should I bring the wheel to a bike shop to have the spokes added/adjusted and the wheel straightened ? Or would a replacement wheel be in order ?

    the shimano gear changer fits on the rear axle and wants to fall off everytime I try to adjust/space the rear wheel - I don't know if this changer is put on correctly, but it has a C shaped opening where it fits onto the rear axle. Because of the orientation of the changer, this C-shaped opening is such that the open part of the bracket faces up. It wants to fall off of the axle, if the right axle nut is anything but tight. This is making adjusting of the rear wheel really difficult. Do I have this assembled correctly ? I was thinking of bringing the changer to work and welding a washer to it, so it no longer has an open slot and can't fall off when I loosen the axle.

    what do you guys figure ?

  2. Mountainman

    Mountainman Active Member

    might be time to think about safty ??

    man oh man johnny
    that's a lot of things going on there
    and please remember -- your safty is involved here
    you mention taking it to work
    when I worked for the City
    many there would bring in bicycles for a little repair by me
    is there someone at your work who has the basic understanding of bikes ?
    if not -- maybe a trip to a bicycle shop -- could be in order ??

    also -- your picture supplied -- stayed very small on my computer ??

    when it's up -- ride that thing Mountainman
  3. johnny q

    johnny q New Member

    thanks for the reply, MM - I was thinking of bringing the gear changer (only) to work. We have some really good tig welders there - aircraft quality. I was thinking of having the mounting bracket modified so the changer can't fall off of the axle when the axle nut is adjusted. And, yes I agree with you big tinme. I think I might have started with a s*it box bike to begin with. Right now, it seems that I have too many issues with the bike itself to be riding anytime soon.

    Also, I 'm getting some kind of strange error message when I go to modify my profile. Where can I go for some help with that ?

  4. Mountainman

    Mountainman Active Member

  5. brendonv

    brendonv Member

    Well with the wheel, if it went wobbly from the sprocket the actual spokes or rim might be crappy quality. You could go down to ur bike shop and get a spoke tool, there about 5 bucks for a tool that can adjust about 8 different spoke sizes. Search truing bike wheel on you tube and there will be videos explaining how to true the wheel. Its pretty simple to do, if the wheel goes out of whack again just true it again. Its cheaper than getting the bike shop to do it.
  6. fetor56

    fetor56 Guest

    Those wheels need to run perfectly true so anything downstream(sprockets/chain) can be aligned perfectly to match....SLIGHTLY off is acceptable but nothing more.
    Start with getting your wheels true.
    See the relevent videos on How To & IF necessary take it to a bike shop:
  7. Knol

    Knol New Member

    I've got about 100 miles on my new Happytime kit. The chain tensioner provided my by my benevolent vendor was apparently designed by some high-level communist party official specifically to maim stupid American capitalists. The poor thing is a rear wheel-locking spoke-shattering mother-of-all-wrecks in embryo. After trying to justify its existence on my install for about 30 seconds, I dremelled two shiny spots on each side of it on the chainstay, fired up the TIG machine and welded the short side into place. I then float tested the pot metal through-bolts that had yielded under the stress of my little 3/8" ratchet, installed AN-5 bolts over ground / hardened washers and torqued the thing into place using MS21042-5 all-metal locknuts. I used an old idler sprocket from a broken sweeper drive gathering dust in the back of the shop and used the stepped axle it was mounted on to mount it through the Happytime bracket. I still dislike the cheap chain, but with the addition of a decent petcock with pipe threads that actually fit the tank (and no crappy finger strainer,) real ASE reinforced fuel lines and stainless worm-drive hose clamps, my favorite inline fuel filter, a Moroso plug indexer kit and some (1/2 inch reach) spark plug technology less than 75 years old, a plug hot enough to survive the idiotic 1:16 break-in oil ratio, (I'm under warranty) I feel a little safer putting around on the thing.
  8. johnny q

    johnny q New Member

    so I have located another (straight I think) rear wheel that I will be getting wed or thurs. I plan to turf the wobbly one on it now.

    I have a question - I saw an excellent post on here a while ago that outlined how to mount the sprocket on the rear wheel and keep the warpage to a minimum. Has anyone seen this post ?
  9. johnny q

    johnny q New Member

    hey people - I think I just located the info I was asking about - posted by Houghmade -

    There are, indeed, better ways of doing this, but believe it or not, this can work quite well.

    The first thing is to make sure the sprocket is flat and straight before mounting it. My 56 tooth was perfect, but my 48 tooth was tweaked. After I discovered that, I staightened it with a vice, a straight-edge and a pry bar.

    Also, when I installed my first sprocket, I snapped several of the bolts- that is, the bolts that came with the kit. I bought 9 new, good quality bolts and have not had an issue. I numbered the bolts holes with a Sharpie so I could keep track of which ones I was tightening and I could tighten bolts across the circle back and forth: 1 then 6, 2 then 7, 3, then 8, 4 then 9, 1 then 5, etc. I tightened in several steps snug, then snugger, then with the torque wrench 5 ft/lbs, 7 ft/lbs, etc. When it was getting close to tight, I ran a straight edge on the sprocket, the measured the distance from the straight edge to the rim at several locations, the tightened more where it was further away. Like I said, worked well.

    Also, make sure the bolts are centered between the spokes so a bolt does not rest against the spoke and put presuure on the spoke when power is applied.

    Finally, centering the sprocket has never been an issue for me because on the coaster hubs I have used, the sprocket hole fits tight, but close around the hub and centers it perfectly. As an aside, I think it is a grave mistake to counsel people to grind out the center hole instead removing the arm and dust cover and ensuring the hole is actually too small before modifying it.