Vintage Whizzer 2 Speed transmission project

Discussion in 'Whizzer Motorized Bicycles' started by ColsonTwinbar, Jun 1, 2016.

  1. ColsonTwinbar

    ColsonTwinbar New Member

    Hey Everybody,
    I'm a longtime member but haven't posted in a few years.
    Heres a project I started on a few months ago (yes it has been going very slow) and is now finally starting to get interesting so I though I would share.

    I first gathered all the components I had and reverse engineered the thing in solidworks. Which i know is kinda ridiculous but it was a rainy winter up here.

    This helped me finalized the modifications I needed to make before I destroyed a few hard to find parts. as well as help me engineer the 3.5 inch pulley that I would need to have made (the larger red component). This will be keyed into the planetary gear drive and ride on a good sized shielded bearing. It is currently just a 3d printed part but will have it turned in aluminum.

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    I used the guts from a bendix manual 2 speed hub http://www.trfindley.com/fl_bike_pages_pics/bndxmsptlst.jpg
    and modified the component that has the three planetary gear axles by cutting off the helical square thread section and grinding down the bearing race. I also shortened the axle and cut the threads where i needed them. For the ring gear/sprocket component I removed the teeth of the sprocket and tack welded it a modified 4.5 inch lawn mower v-belt pully. Reducing this pulley size will give me a slightly higher gearing than the original 5 inch pulley when in my high gear (1:1) while having a decent lower gear to work with.

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  2. ColsonTwinbar

    ColsonTwinbar New Member

    I was lucky enough that I happened to find a clutch arm for the auto clutch, which is much thinner than the stock version, and gives me the space I need for the new bearing but will have to add the clutch cable slot to it.

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    The little axle sticking out was made from a 1/2-13 socket head cap screw with the OD turned down to fit in the bearing and the center drilled and tapped to accept the 3/8-24 threads of the axle. This will be silver soldered in place later but still need to figure out how to lock the axle in place.

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  3. ColsonTwinbar

    ColsonTwinbar New Member

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    With my big tires its a pretty tight tolerance between my frame and tire, as well as my seatpost, but after getting it on there it seems to fit better than the original!

    After its all finished I fear it may have the same problem that the original 2 speeds had -they supposedly eject all their grease because the unsealed bearings have to spin too fast. I found a 35mmx4mmx7mm sealed bearing that could replace the main bearing with a fair bit of machining (of hardened steel) which will be a pain.

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    I have still yet to figure out the best way to shorten the axle on the outside because it interferes with pedaling, but it will require shortening the shifting pin and spring and some strategically placed cable pulleys if I wanted to do a New Departure DD style shifter. Or I could make a fixture that a cable housing could push off of.

    I'll be posing more as the project continues, I hope you guys like this ridiculous project as much as I have been.
     
  4. Tony01

    Tony01 Member

    Very nice. I built a twin js/twin clutch 2-speed auto. I'm working on a planetary geared automatic currently also just working on it in solid works. I will be using an automotive gear set and have not yet figured out how to keep the lube inside due in part to the helical gears (which are a pita to draw!! I gave up).

    Believe me you will love the shifter. Especially if you keep it manual you'll have engine braking in both gears (my first gear in the current and future setups is always freewheeling). That gear set appears to have at least a 1.5x reduction so you're good. I'm running a 1.6 right now which is great for street but I feel like drag racing would be better with a smaller jump to get into the top gear already in the motors powerband.

    BTW if you find a small enough ravigneaux gear set you could get 2 under drives with 3rd direct. I'd love to do a setup like this but it just seems like a lot more work than one sprag bearing and one clutch.
     

    Attached Files:

  5. ColsonTwinbar

    ColsonTwinbar New Member

    Thanks, is that photo the one you made? This one is tiny so I'm hoping it will be strong enough. If I removed the seatpost like you did I could flip the axle of the unit, letting the main (high) gear be the default as far as the spring is concerned and get it out of the way of my leg.
     
  6. Tony01

    Tony01 Member

    image.jpeg Yea it sure is tiny. Keep this updated!! Actually on mine I didn't remove the seatpost, the transmission bolted to the seat tube. I turned it back around to fit a new motor- same transmission and a hell of a lot more chain stretch.

    Gears need to be oiled or they will grenade. I might figure some splash setup and fluid level sight glass.
     
    Last edited: Aug 10, 2016
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