Chain Tensioner custom idler gear (home made) pics too

Discussion in 'Transmission / Drivetrain' started by double trouble, Sep 20, 2011.

  1. By the way , this is my second post so bear with me. I have not had a little motor bike in 35 years. nothing ever like this. Its for my kid ,but I might buy or build another. They are fun. I bought this one used for $130 . It needed a lot.
    I had to make a custom idler gear because the 2 different cheap plastic ones were broken. I think the back wheel was bent when the chain locked. I put a new back wheel on with a new tire. The previous owner gave me a back wheel but it needed truing too.
    The idler setup is the upgraded spring loaded one with a 2 bearing home made split gear from a pulley setup i bought at a flea market for $2 . I used the halves as a race press to put a bearing in a Neptune washing machine and they were lying around till I had the idea to flip them and use them as an idler wheel. I had some heavy moly industrial chain lube that works well on the chain.. I had to reinforce the idler slot with a piece of angle iron too. It bent badly when I ran out of gas and the chain locked up. It handles the extra weight of my metal idler.

    Here is a link to another site I was asking questions about before I found this one with pictures of my bike.

    Looks pretty good except I have to cut the angle iron down with my cut off wheel. lots of other questions too.

  2. motorpsycho

    motorpsycho Active Member

    wow, that's pretty crude looking in my opinion.
    most tensioners have the chain running under them, not over the top of them.
    this keeps more chain in contact wit the rear sprocket (more chain links are wrapped around the sprocket.
    with yours it's actually taking some of the chain off of the sprocket.
    I'm not saying that it's right or wrong...whatever works for you.
  3. happycheapskate

    happycheapskate Active Member

    I didn't like the moly chain lube I tried. It had a hardening agent which built up on the derailleur pulleys and chain. Oh well, everyone uses different things till they find what they like.

    Welcome to motoredbikes! Here is your photo on Sadpanda hosting service. (free)


    That is cool you are getting a mb for your kid. I would have loved one of these when I was a child. I rode bicycles from kindergarten and still do. The mb is my "poor man's motorcycle".
    Last edited: Sep 21, 2011
  4. crude but working

    I did not know the chain would be better off under the pulley. The bracket did not look to be mounted that way and the spring would not work like that. I'm new to all this. I did cut the angle off the bracket so it does not look so cheesy.
  5. RedBaronX

    RedBaronX Member

    yeah, as in "if you start building one, you'll be poor! at least that's how mine is turning out... (but I'm also upgrading parts wherever I can)

  6. not too bad

    I just upgraded the spark plug wire from an old prestolite 7mm wire off my spare coil wire from my old 75 hp Johnson . it fit perfect . we'll see if it runs tomorrow.
    I have a new picture with a couple accessories on it. need to figure out how to post without image shack.
  7. happycheapskate

    happycheapskate Active Member

    Double Trouble, your idler looks like that kind many have made on this site. (lifts up bottom run of chain returning to wheel cog). I don't see why it should have any trouble unless the spring is too tight or too loose, or the arm sways, allowing chain derailment. It looks ok. Does it move a lot when you dump the clutch to start the bike?

    Use . It's free and very reliable. You don't need an account. I "send a beer" to the owner of site sometimes, to say thanks.

    Maybe it will work here. This is the home-made idler/dampener on mine, as you requested.
    [​IMG] It's on my user page or pm for details. I made it for $20. Before I installed it, I had major vibration, now I can use my mirrors and my feet do not get numb at all, been using it for months.
    Last edited: Sep 21, 2011
  8. Mine is o.k.

    I cut the angle iron today. Of course I cut my spring by accident and got a spark from the grinding in my eye. My plastic face shield was sitting next to me. I took it off to check why I cut the spring and forgot to put it on when I threw sparks in my eye. Really pretty funny. The eye is o.k. after a few hours. Not the first rodeo with a grinder. Took the bike for a 10 mile cruise. ran great. I like my free roller idler setup so far. I might need a softer spring because of my stupidity , but its all part of the learning. A rubber idler would be quieter so I might look for one off an old dryer tumbler . I get lots of ideas this way. free stuff too. My new pic is in the gallery.