Motor on a 3 Speed

Discussion in 'General Questions' started by bigredmachine, Oct 20, 2009.

  1. bigredmachine

    bigredmachine New Member

    Hey guys I just joined the forum..after seeing a couple gas powered bicycles on campus I decided to do some research and discovered this site, which has been very informative! Yahoo actually sent me to the "Crash course for NOOBS" post which was extremely helpful. I recently went on craigslist and bought an old 3 speed western flyer bicycle to ride and to later put a motor on...a have a couple questions about this:
    1. Can a motor be put on a 3 speed bicycle such as this that has an internal hub mechanism?/will I be able to just shift through the gears?
    2. The shifter is the whole right handlebar (it just twists to change gears) is this affected with the throttles that replace the current handlebars?
    3. If the above 2 questions havent already counted me out..I go to school at the University of Cincinnati and live in the same neighborhood, which is VERY there a way that I can sacrifice top speed for more hill climbing power?

    If there is anything else I should know please share!
    Thanks! Sid

  2. jimraysr

    jimraysr Member


    I just moved the shifter over to the left handlebar for my 7 speed.

    I personally don't like the rag joint drive, but originally installed it on my spokes, then got a hub adapter and sprocket from Manic Mechanic ( ) which clamps on the hub. We have a three speed trike and I am guessing hub is too large for one of Jim's adapters plus ours has a Zerk grease fitting sticking out in the center (between the spokes) WRONG!

    I was wrong, Jim (Just spoke with them in FL) can make a hub adapter to fit around the three speed transmission. That and the sprocket will work with either a 2 or 4 stroke

    The other choice would be a jack shaft drive ( for 2 strile) using the bike chain and the 3 speed. I am not sure a three speed is strong enough for an engine drive?

    So all I have given you is about the handlebar and shifter, the rest can be answered by fellows with direct experience.

    I think you will find there are a lot of field fixed worked out by the forum guys. That is the fun of it. Always something to tinker with.

    Good luck and welcome to the adventure.

  3. bigredmachine

    bigredmachine New Member

    Sorry im new to this, but does this mean that a standard motor kit wont work for my bike?
  4. jimraysr

    jimraysr Member

    Frame Size

    Most any full size bike will take a 2 stroke, but the 4 stroke takes a lot of space and it took me a long time looking at new bikes to find one that the Honda would mount in.

    It might help if you could post a picture and measure the length of the seat post, bottom tube and top tube.

    I am only on my second build. First is a Schwinn Searcher, Honda, Grubee box and Manic Mechanic hub adapter. Second will be a 2 stroke.

  5. bigredmachine

    bigredmachine New Member

    The size isn't what concerns me..what worries me is the rear hub. Im not sure how the rear sprocket attaches to the hub but it looks like the hub is bigger and extends on the other side of the wheel where the sprocket would go? I know this is far from descriptive so maybe I will try and take a picture...
  6. jimraysr

    jimraysr Member

    3 Speed Transmission / Sprocket Drive

    OK, Most kits include what we call a rag joint. That is two donuts of fabric and rubber, plus two two or three section metal rings, same size as the rubber donuts and having 9 holes total.

    The builder places one of the donuts (after cutting it at one place) inside the spokes and three of the metal sections. Likewise the other two rubber and metal donuts on the outside. Then place the rear drive sprocket on top and start inserting the 9 bolts. The nuts and lock washers go inside.

    Long story, short, the spokes are sandwiched in the center of this mess (sorry) and that is what the motor dirves.

    If you get one of Manic Mechanic's hub adapters, it clamps around your transmission hub and the engine drives the rear wheel same as the regular bike chain.

    Take a look as some of the sponsors of this forum ads and some have install videos that will show you much better how this is all done.

    Also a lot of the guys post pictures of their bikes and you can look at them and see how it all works.

    At first it is a little confusing, but after a while when somebody says the chain idler, you will know it is little nylon wheel between the rear sprocket and the engine that keeps the chain tight and on the sprockets.

    Go to BcycleEngine, they have an install guide:

    Also Thats Dax:

    That is two dealers who have instructions posted.

    Keep asking questions that is the way we all learn.

  7. bigredmachine

    bigredmachine New Member

    Thanks for the info Jim..i need to measure my hub and see if it matches the measurement on the kits. The installation guide mentions a 36.9mm center hole diameter for the rear drive this standard to all kits?
  8. jimraysr

    jimraysr Member

    Sprocket Center Hole Provided In Kits

    I would guess that is the size in both of the spare ones I have, about 1.5".

    I have seen mention of grinding the hole larger with a Drimel or equal to grind the hole larger if you hub was larger.

    I have Drimels, but don't think they are up to the job, especially for your hub. I would use a die grinder for the job myself. You could probably find a metal grinding stone at a tool store like Harbor Freight to use in an electric drill.

    I don't think you would have to worry if the sprocket didn't hit the spokes when you tighten up the rag joint bolts.

  9. Esteban

    Esteban Active Member

    Friction drive would be an alternative that would be much simpler to install.
  10. loquin

    loquin Active Member

    At this point, you need to make a decision as to what type of kit you're looking at.

    The friction drive kits (Staton, Dimension Edge) are, as Esteban pointed out, the easiest to install, They're rack mount, sitting atop the rear tire. They are medium expense, but, if used with a good quality motor, very reliable. They don't work as well in the rain as chain/belt drives, though. (You have to adjust them properly, and keep the air pressure up in the tire.) They do tend to wear the rear tires a little faster than a chain or belt driven kit does.

    Frame mount, (the motor sits inside the frame, similar to a motorcycle) two-stroke kits ("Happy Time") are the low cost solution, but, they are also the poorest quality kits, are the most difficult to get installed and set up, and have the highest maintenance.

    Frame mount 4-stroke (Titan) kits with clone engines are medium cost approaches, which may require a wider crank (which may be a problem finding parts for an old three-speed bike.) They certainly appear to be higher quality than the "Happy Time" kits, but, based on issues posted here, they do not seem to approach the Honda/Robins-Suburu engines in quality.)

    The EZM frame mount kits have good power, are similar to the other frame mounts in installation complexity, but are higher cost.

    Rack mount chain drive (aka Staton) or toothed belt drive (GEBE) are the medium complexity, higher cost, and higher quality solutions.

    The Clone (Titan) 4-stroke rack mount kits are medium complexity installs, and, since they use the clone engines, are medium quality as well. The appear to be about the same cost as friction drive kits.
  11. bigredmachine

    bigredmachine New Member

    I would really like to go the frame mount route just for cost and aesthetics purposes...I'm thinking that I could just get a new rear wheel that has a compatible sized hub and just make the bike a single speed with an engine kit