How to Solve Chain Clearance Issue?

Discussion in 'Frame Mounted Engines' started by npk1977, Aug 7, 2007.

  1. npk1977

    npk1977 Guest


    My frame's width is not great for these kits, and my chain was rubbing against the frame. To fix this problem, I put the chain tensioner really close to the sprocket, so that the chain passes the frame at its widest point.

    However, even after using a self-tapped screw to hold the tensioner in place, the chain still keeps coming off! I shortened the chain, but now it's too short to have the tensioner close to the sprocket.

    I see four options:

    1) Get a longer chain, but putting the chain back together seems like a real pain in the ***. I spent an hour trying to do it and I could not.

    2) Flip the sprocket, so that it's concave facing in. I think that would solve the chain clearing the frame issue, not sure about chain rubbing the wheel.

    3) Try to spread the frame apart 1mm with brute force.

    4) Do nothing, let the chain cut a nice groove in my frame :) This is not really an option.

    Help! :)

  2. azbill

    azbill Active Member

    try using washers between the sprocket and the frame
    2-3 should help !
    Last edited: Aug 7, 2007
  3. clear your frame/chain

    Check out the way Whizzer gains a little space for belt clearance. There are notches built into the frames that allow another 1/2 inch of clearance on the inside of the tubing for their belts. You will probably have to actually cut these into your frame to keep the same motor position & rear sprocket the same as it is now. If you change either or both of these it can cause other clearance problems in other places.(crank arms) A straight chain path is a happy chain path.
    So option #5...
    Cut your frame tubing to allow approx 3 inch notches (for vertical travel)where the frame actually looks flat in these areas. Flatten the pieces that you cut out & weld or get somebody to weld the flat pieces back into the hollow space that you create. I can send a pic of a Whizzer frame if that will give you a better visual. This will weaken your frame if not reinforced well, so beef it up on the opposing side of the tubing.
  4. npk1977

    npk1977 Guest

    Guys, I used the washer technique, it's fantastic, thank you.

    Also, thank you for the whizzer idea. Turns out I didn't need it.

    HERPER Member

    i was just about to tell you the washer option, i had a similar problem when i began and i had to do the same thing. the only downfall.. its makes its painfully hard to put the wheel back on the frame when you pop it off. at least for me, becuase you had to spread the frame and slide it in all at the same time..good time for another person
  6. Jacking out for clearance

    Hi guys, Yes Whizzer has always used a "Dimpled" frame which gives clearance and is strong. I did this on one of my bikes by making a 1/4 inch plate 1-1/2 to 2" wide, ROUND all of the square corners, and with a 5 lb hammer, pound the dimples into the tubing, when you are done it will look a little like a B U TT crack. this works very well, but mine was chromoloy and was very tough to do.

    Your wheel is hard to put back on with washers? Awww gee amigo, do what I did, go out to wifey's lil Honda, or Hyundai, or Kia or whatever and get her sizzor jack.

    Place this in the dropouts and in two or 3 seperate jack open, let it relax, and repeat, get your dropout to be about 1/8 to 3/16 wider than the rear wheel assy.

    When you tighten back up, it will "spring" in for a very nice fit.

    I hope this will help someone.