Mounting question for rack

Discussion in 'Rack Mounted Engines' started by D_Station, May 17, 2009.

  1. D_Station

    D_Station New Member

    Hey, so im working on a bike, and im gonna do a chain drive. I want to mount the motor on a rack, and i was wondering how you guys effectively attach the motor so that it stays still. I don't want to put the motor on just to have the torque twist it off the rack or anything. Thanks for the help.
    D Station

  2. bamabikeguy

    bamabikeguy Active Member

    I'm presuming Staton's mount is notched to fit over the axles, similar to the GEBE set up?

    If it is, these are the basic steps I do to attach the mount to the frame.

    There are (2) 5 mm. holes over each axle slot. I attach a 2 1/2" pc. of steel above the axle slot, and drill a 3/8" hole through the steel pieces.

    Then you will have to cut the ends off the motor/axle mount.

    First you will have to establish the distance between the axle and the bottom of the mount. I have a threaded rod with 4 wingnuts I slip in the axle slot, but first time I simply tied a golf club in that slot, to serve as the "axle".

    Then you put the mount over the "psuedo-axle", measure the distance in millimeters, axle to bottom of mount.

    Cut the excess, clamp the mount to the steel piece, to drill the 3/8" hole, and whoola, the mount is now part of the bike

    Attached Files:

  3. fetor56

    fetor56 Guest

    Search the different vendors & see their chain drive rack setups.Some are better than others,then please ask more specific questions.

    PS...i'll help narrow it down:
    Dax,same thing)
    Last edited by a moderator: May 17, 2009
  4. 5-7HEAVEN

    5-7HEAVEN Guest

  5. 5-7HEAVEN

    5-7HEAVEN Guest

    :idea:Follow D. Staton the vendor kit guru.

    He uses a hinged U-bracket up front, a support strut to brace that mount and a rear support strut to lock down the rear of the gearbox.
  6. D_Station

    D_Station New Member

  7. D_Station

    D_Station New Member

    and ill make sure to make my questions more specific next time. Thanks so much for the help i really appreciate this forum alot
  8. bamabikeguy

    bamabikeguy Active Member

    Looking at the picture, I'd still put two legs on it, and extend it down to the two dropouts above the axle slot.

    Having the engine supported only off the seat post would be unique, that's for sure.
  9. fetor56

    fetor56 Guest

  10. 5-7HEAVEN

    5-7HEAVEN Guest

    JMO but weedwhacker engine would not be effective with chain drive.:whistling:

    You will probably be needing 19:1 or higher (numerically) gear ratios. If you were to put a 10-tooth sprocket on the engine, you'd need a 190-tooth sprocket on the rear wheel.

    Unless you use a jackshaft. Then 10-tooth on engine and a 44-tooth on jackshaft. At the other end of the jackshaft, place another 10-tooth sprocket. Then a 44-tooth sprocket mounts on the rear tire.

    That combination will give you 19.36:1 gearing.

    It's easier to use friction drive.:idea:
  11. D_Station

    D_Station New Member

    ok, thanks for the info, and just wondering, what sort of motor would be suitable for a chain drive then? and yeah, my motor definitely is way weaker than i thought, its only 18 cc i discovered, so i might get a better motor
  12. bamabikeguy

    bamabikeguy Active Member

    18 cc? No way.

    The 30's-40's cc type 2 strokes would be 1.5 hp+++, you're talking about moving 200+ pounds up and down hills, not beating up tender blades of grass.

    Even the 25cc Red Maxes won't pull the new fangled clutches.
  13. D_Station

    D_Station New Member

    yeah, thats what i figured, so i am definitely getting a better motor, ill see what i can find, but so would you say, like maybe 50 or 60 cc then?
  14. loquin

    loquin Active Member

    35-50 cc.

    Many folks use the robbins suburu or Honda 35cc (apx) , or the Honda 50cc 4 stroke engines.

    I have a mitsubishi 43cc 2-stroke engine.

    the 35-50cc engine range is about right. Many states have laws which limit engine size to 50cc or less...
  15. bamabikeguy

    bamabikeguy Active Member

    Not for a rack mount, 90% the engines in this category, chain, friction or belt, are Japanese units, less than 40 cc.

    Those bigger numbers, are the mostly Chinese made units that fit between your legs, mostly chain driven, but the Whizzers use belts.
    Last edited: May 18, 2009
  16. D_Station

    D_Station New Member

    and yeah, i weight about 150 pounds and have a kinda small bike, this is more of a summer project and show off to friends kinda deal. Idk about riding it to school or anything, but yeah, im definitely gonna get a better motor then
  17. fetor56

    fetor56 Guest

    35cc+(the quality of the motor has alot to do with how it performs)
  18. bamabikeguy

    bamabikeguy Active Member

    Since you are into robotics and metal working, designing it yourself, dave's thread about "chainsaws, weedwackers, snowblowers...." would probably interest you.

    There are few more DIYer's that have some nifty setups, and a lot of them are in that thread above.
  19. D_Station

    D_Station New Member

    Last edited: May 26, 2009