Belt drive kits for the basic 80 cc two stroke

Discussion in 'Spare Parts, Tools & Product Developement' started by buzbikebklyn1, Jun 2, 2009.

  1. buzbikebklyn1

    buzbikebklyn1 New Member

    I've been looking for belt final drive kit that can be retrofitted to the basic 80cc two stroke frame mounted kit...
    I need to do away with the extra chain so I can keep my rear brake disc.
    Any vendors out there market anything like that?
    Tom.M -AKA- buzbikebklyn1:D

  2. MotorBicycleRacing

    MotorBicycleRacing Well-Known Member

    How much would you be willing to pay for such a belt drive upgrade?
  3. ocscully

    ocscully Member

    To the best of my knowledge no one offers a kit to accomplish what you want, Belt drive to the rear wheel. Jim from Creative Engineering is working on a custom toothed timing belt drivtrain for a couple of motorized Spoilers/choppers. You might contact him to see if he has anything ready for resale to the general public. You also might look at the Sick Bike Parts Shifter Kit. Its essentially a jackshaft system that mounts to the motor and transfers the drive to the right side of the bike and then to a freewheeling front crankset (included with the kit) and then the normal bike chain drives the bike from the right side.

  4. Tom,

    I've been working on it, along with a gazillion other things :grin5:

    When I first started looking at building up a Schwinn Spoiler, I wanted to retain all of the original functionality and looks of the bike.

    Kawasaki asked if I could do a belt drive set-up with the Chinese in-frame 2-stroke. It was a perfect solution to a number of problems. With the disc brake there is very little room in the rear for a drive...The belt set-up is perfect.

    I'm going to use an SRAM internal 3-speed hub as a transmission that will be mounted just behind the seat post. This set-up will freewheel with the engine off, so that the bike can be easily pedaled when necessary.

    I couldn't find any commercially available cogs that could be used without a lot of modification, so I bought lengths of hobbed material to make my own cogs. Notice that the smallest diameter bar is a different color. It is steel for the engine cog.


    1) Shop photo
    2) Cog Material, an assortment of timing belts, cog to hub adapters, and some other bits we make here at the shop.
    3) Cog adapter fresh off the CNC, and a custom made Cog ready for the rear wheel.
    4) Adapter and Cog mounted. Everything cleared perfect so that the rear disc brake did not have to be modified or cobbled up in any way.
    5) Belt and a mock-up of the SRAM and custom bracket. I wire tied it to the frame just to get some measurements.


    Attached Files:

  5. Happy Valley

    Happy Valley Active Member

    Wow, some fantastic looking production from scratch going on there and nice shop. Oh, to have that skillset.

    My partner is a bicycle mechanic with 20 years of wrenching and with experience innovating transfer hubs on custom MTBs for a clientele of racers and hard core enthusiasts.

    Though using chain, the ideas are similar and offer some very interesting possibilities, chainline alteration and transfer gearing.

    Horizontal dropouts welded in place to mount the transfer hub, nice touch with the QR skewer and threaded adjusters.


    In this particular application, the final drive goes to a 14 speed Rohloff hub.
  6. uncle_punk13

    uncle_punk13 Guest

    What make/model is your VMC? Gawd I can't wait for the economy to pick up again so I can get back to running those for my livin'...:cool:
  7. Cool stuff HV...I don't know that much about bicycle stuff. I assume this was done to increase ground clearance for rough terrain riding?

    There is some question as to whether or not the internal hubs will handle the torque from a small engine. I have read that the Sturmey Archer, and Shimano hubs don't last. A local bike shop said that SRAM hubs were the toughest that they had used. I don't's a experiment. One thing is certain: with this set-up, if a hub does fail, it's easy to swap out.

    I do know that these hubs have to be set-up properly, (the shift cable adjustment), and I would assume that smooth shifts under engine power would greatly increase hub life.

    UP13...The CNC is a Leadwell MCV750XL. It has a 20X30 envelope, box way, Fanuc control, 24 station tool turret, 40 Taper, RS232 data tranfer port. It is a great old machine, very accurate.

    I know what ya mean...I haven't had any commercial work since mid December. Everything has just dried up!

  8. Happy Valley

    Happy Valley Active Member

    Hey Jim

    In the case above the transfer hub was used to alter chain line to fit around the fat 3.7 endomorph tires. That particular frame already has loads of ground clearance. My bud has used geared transfer hubs to offer multi primary drive ratios choices.

    As to the torque question, I don't think it will be a problem strictly speaking. A 200 lb. mountain biker off the seat and cranking (200 ft-lbs) is creating gads more torque than any small engine can muster. (Honda 50cc 40 ft-lbs).
    Drive train slap might be a bigger issues but seems that would be buffered substantially with belt drive.
  9. fasteddy

    fasteddy Member

    Know what you mean about work.A friend of mine who is an auctioneer in upstate NY has sold out 3 local machine shops in the last 6 months.

    When things pick up who's left to do the work?

  10. HoughMade

    HoughMade Guest

    Kings Sales and Service sells an adapter to allow the use of a disc and a sprocket for the chain.
  11. Hough,

    The Schwinn Spoiler frame is different.

    You can be assured that I have looked this frame over very carefully.

    The idea is: don't alter the original bike! Add an engine without cobbling-up the rest of it.

  12. HoughMade

    HoughMade Guest

    I should have been more specific, Jim. I was referring to the original poster's issue.
  13. Quenton Guenther

    Quenton Guenther Motored Bikes Sponsor

    Hi everyone,

    Sorry I haven't responded to this post earlier, but my little machine shop is working overtime! There are several ways to convert to belt drive and several have used the rear belt drive system on the new EZM kit. Simply install the Whizzer rear belt sheeve and make a "V" belt pulley to fit on the output stage of the motor gearbox [or drive system on the EZM]. Our EZM kit is setup to either use the chain sprocket or pulley at the output stage of our drive system, and the rear belt sheeve can be purchased from any Whizzer dealership or from Memory Lane Classics [Ohio]. The sheeve from Memory Lane Classics is a repop of the vintage assembly and only requires a series of washers, nuts & bolts to attach, whereas the unit from current Whizzer sealers requires the brackets [more expensive] to mount to the wheel.

    Have fun,

    Attached Files:

    • 1f.jpg
      File size:
      174 KB
    Last edited: Jun 11, 2009
  14. I would be concerned if one was to put a belt drive on a HT unless you have a pull start HT then it should be ok because if you bump start it will the belt hold? Also there's the gearing. It seems a belt drive needs a bigger pulley on the back wheel to distribute the load a bit better on top of getting the right gear. With a HT you'll need that rear wheel pulley smaller and that may add to the strain of the belt.

    Just my 2 cents.
  15. KilroyCD

    KilroyCD Active Member

    Large, about the only way to start a Whizzer is to pedal it (whether it's on the center stand or if you're riding it), so the belt can usually take the strain of a bump start. That is, as long as it's a decent quality belt like a gates, NAPA, Goodyear or similar.
  16. srdavo

    srdavo Active Member

    doesn't the compression release allow the whizzer to turn over a little easier?
  17. Kilroy is right Large.

    I'm using Browning belts that are rated for 12H.P. at 2,000RPM. The HT countershaft spins at about 1,400RPM near the upper end, and the engine produces ? < 12H.P.

    The critical thing with cog belts is tension...they must be tensioned correctly at all times.

  18. strotter

    strotter Member

    Looks cool