Having trouble keeping chain tight

Discussion in 'General Questions' started by plinko, May 25, 2010.

  1. plinko

    plinko Banned

    I built my bike and runs well.Just one Issue.The 415 chain will not stay tight. Chain Is broke In.Not overtightened.And pulley seems to not be shifting.And sometimes when I stop my bike and roll It manually and feel pressure on the chain.Certain areas seem looser than others.Someone please advise me on this Issue.

  2. motorpsycho

    motorpsycho Active Member

    it's the rear sprocket. they are not very precise and almost all of these kits experience the "loose, tight , loose" chain syndrome as the bike rolls. the sprocket will not be perfectly centered on the rear wheel in most cases. I have the same problem and i've struggled with it. i have it centered on the rear wheel as best as possible, but i still have the same problem as you are having. I've just learned to live with it, but i have a spring loaded chain tensioner coming that may solve the problem. The chain tensioner that i got, is not for motorized bikes, but it's much better looking than the stock idler wheel that the kits come with. the difference is that the one i got has spring tension, so it will move up & down as the chain gets loose, and then tight. it will keep the chain at a constant tightness as it rolls. I have not gotten it yet, so i'm not sure exactly how well it will work yet. it was cheap, and it's made from aluminum with a high speed bearing in the tensioner wheel..plus, it's adjustable.
    There are also sprocket adapters that allow you to get the rear sprocket centered perfectly on the back wheel, but they are expensive.
  3. plinko

    plinko Banned

    Redid the sprocket with a micrometer and eliminated 90 percent of my problem.Took a while.But It's a lot better now.Think I may go to tractor supply and pick up a sprocket and drill out the holes and see If that will be better.Steel was not chromed.But,Seemed to be heavy duty and weighed more than the stock ht sprocket.
  4. this works pretty good

    This is an autotension system made from the stock one and the bar from the through the frame mount. nuts were welded so the pivot bolt can be locked in place with nut.

    Attached Files:

  5. motorpsycho

    motorpsycho Active Member

    The tensioner that i got was not exactly what i had in mind. But i was able to make one out of the peices from it. It's actually a tensioner for a downhill / mountain bike that has been converted to one speed. it takes the place of the derailer.
    I was able to modify it to make it into a floating chain tensioner. I got a longer 6 mm screw to go through the side cover. I put a brass bushing into a peice of aluminum that i made, and the bushing slides over the longer side cover screw. the tensioner moves up & down freely because of the bushing. i added a spring to supply tension so the tensioner is always being pulled down. the gear on the tensioner is steel, and the whole thing rides up & down with the chain keeping constant pressure on it, and it keeps the chain tight. even tho my chain does the "loose, tight, loose" thing as it moves, this tensioner eliminates the loose spot by moving down as the chain gets loose, and putting tension on it. it works great and it made a world of difference. riding my bike before, i was always afraid that the chain was going to come off because it would start bouncing up & down. most people put their tensioners at the rear so there is more chain wrapped around the rear sprocket. but i put mine in the front and it does the same job. I wanted to kind of make it blend in with the motor because i don't like the look of a tensioner bolted to the side of the frame.
  6. Tinsmith

    Tinsmith New Member

    I went with a spring loaded sprocket tensioner setup. Haven't touched it since I put it on over a year ago.