Left side Deraileur

Discussion in 'Performance Mods' started by andyinchville1, Nov 23, 2007.

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  1. HI All,

    Just looking at my mountain bike today and got to thinking....would it be possible to attach the derailleur (obviously it would have to be modded) so that it would run on the left side....It would then be possible to use maybe 2 sprockets for the engine to drive (would have to find a more sturdy mount than the 9 hole rubber mount....maybe using the disc brake mounting system and having twin sprockets made for that)....I realize that the derailleur would want to "wind up"
    when the engine is compression started but maybe that problem could be solved by welding stops onto the derailleur to limit "wind up"....Probably could only fit 2 or 3 sprockets at the max on the left side without major widening of the chainstays but heck I'd even be happy with 2 speeds at this point.....what do you think?

  2. I was thinking about this myself - it would be sweet in theory... especially if you used lightweight sprockets.

    I don't have the tools or technical know-how to pull this one off but I'd love to see someone do it.
  3. Haggard

    Haggard Guest

    I tryed couldnt get it to function right. messed with it a couple days but no luck . whenn deaccelerating, because the sprocket doesnt freewheel, the chain and derailuer would get bunged up as the chain would theoreticly be pulling in the opposite direction if you follow me. .let me know if you get it to work
    Last edited by a moderator: Nov 28, 2007
  4. Alaskavan

    Alaskavan Guest

    Couldn't you avoid a lot of problems by having a freewheel on the left, and a pull-start on the engine?
  5. Hmmmm....Interesting that you have already tried Haggard....Back in the old days my sister had a 10 speed where the front chain rings would freewheel and the read cogs were fixed (the selling point was that you could shift while coasting).....seemed to work OK....maybe a problem with the derailleur you were working with or maybe there is a special anti wrap up mechanism on the derailleur for that type of setup?....In any event, I think the bike is still at my grandfathers house in Michigan....I will definitely have to look at it when I visit later this winter.....
  6. HI Alaska,

    Good points....but I wonder how difficult it would be to retrofit a pull start on a happy time?
    Hmmmmm....but then again, may have to widen the cranks to allow for the recoil mechanism width.....aaarg....one step forward and 2 steps back?.....I wish a factory could just make us the ultimate setup....Ooops but then again that's no fun because then we wouldn't have to mod anything then!
  7. 5-7HEAVEN

    5-7HEAVEN Guest

    :cool:Andy, there are retrofit pullstart assemblies for happytime on the market.

    I'm thinking about installing a pullstart mechanism when I install a jackshaft for my twin-engine project.

    While tinkering with my "RODGER Box", I realized that an adaptor pawl could probably be attached onto the engine's crankshaft snout. This would protrude through the aluminum cover so that the starter pawl could be engaged with a cordless drill's socket attachment. Then the engine could be cranked and started ala 1909 EXCELSIOR DOHC.

  8. HI 5-7 any links for the recoil start for the happy time?....I saw one awhile back but it was for the GGG model (give gas go....centrifical clutch model happy time type engine)....I like the drill start idea....have to carry a holster to carry the drill tho....Hmmm
  9. 5-7HEAVEN

    5-7HEAVEN Guest

    :cool:Andy, I too saw the retrofit parts online, but I forget which site.

    That cordless drill might be the screwdriver-type, less than 2 pounds, and strapped to the frame under the tank.

  10. Bean Oil

    Bean Oil Guest

    A left-side derailleur would have to be completely re-engineered from scratch to be an exact mirror-image of the traditional right-side unit to work well and reliably.

    I wouldn't necessarily like a freewheel dealibob (sprag, one-way, etc...) on the motor's drive chain path because then there'd be no more engine braking upon throttle closure.

    /me thinking out loud