Chain Tensioner chain tensioner...use a rear derailer?

Discussion in 'Transmission / Drivetrain' started by CPC, Apr 10, 2009.

  1. CPC

    CPC Member

    Ok, Im sick of using the junk chain tensioner my kit came with....noisy, not enough adjustment, PLASTIC above all things, and no bearings. So I was brain storming and think I can use a spare rear derailer as a spring loaded chain tensioner. Has anyone tried this approach yet?

  2. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

  3. CPC

    CPC Member

    wonderful, sorta like I had in mind, guess Ill have to get off my butt and give it a try! Thanks!
  4. nsideus

    nsideus Guest

    This is real simple works great and takes about 20 min. The one in the picture is 4.5" the one on the bike is 5.5". Make sure the arm moves freely where it connects to the original mount.

    Attached Files:

    Last edited by a moderator: Apr 11, 2009
  5. CPC

    CPC Member

    thanks, Ill give that a try if the rear derailleur doesn't work as planed or is tooo noisy....I want quite, and next project after tensioner is a new exhust setup, cant get fiberglass wrap in the stock muffler, so going to fabricate my own with expantion chamber and hopefully a noise reduction by at least 50%
  6. nsideus

    nsideus Guest

    The derailer works great only problem is the springs tend to break around 1,000 mi. Might be more of a problem for me because I run a 56th they are not very round.
  7. nsideus

    nsideus Guest

    I need to add a note here. The derailer tensioner may only work on 4-strokes 2-strokes create too much pressure at start up and may cause chain to bind. The simple tensioner above may/has bind also, a solution is limiting the movment of the arm (working on this). The bar spring tensioner works very well on the Grubee 4-strokes the picture above is on a 4-stroke.