New Kit Idea

Discussion in 'Motorized Bicycle General Discussion' started by ferball, Aug 2, 2011.

  1. ferball

    ferball New Member

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    I have been messing around with DIY Weed Whacker friction drive build and the process has been fun. Since I my budget for builds is usually $0 I usually repurpose and reuse things as I tinker in my secret laboratory. So today I had a great for a low cost bolt on kit for motorizing bikes.

    Make a kit that utilizes the gearbox/gear head of a weedwhacker. The gearbox on a weedwacker could be mounted in a variety of ways, to accomadate friction or chain drive and the selling point of this kit is that the engines would be dirt cheap, the gear box are pretty universal how they mate to a string trimmer engine, so you could use almost any 10 dollar craigslist trimmer for a motor, and because it will be using the flex shaft you might be able to come up with an inframe mount if you wanted. Also because the bolt on portion is the gear head, you would not have to strip down the engine and figure out shaft adapters and stuff, and many already have a centrifgal clutch that would function just fine.

    So any way I have a string trimmer gear box, and I have changed from trying to come up with a decent engine mount and drive set up to figuring out a decent gear box mount and drive setup, then the engine becomes plug and play, easily swapped out and changed with out having to reinvent the wheel.
     
  2. ferball

    ferball New Member

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  3. wayne z

    wayne z New Member

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    Take This idea even farther. Do a search for pole saw gearboxes. They're 90 deg and built for more horsepower.
     
  4. ferball

    ferball New Member

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    Is the pole saw gear box as universal as a string trimmer? That is the part I am seeing as being realy cool, most any trimmer engine can be plugged into the thing with very little effort.

    Chainsaw would make better engines, a little more expensive, but the pole saw box might be the interface for saw engines.
     
  5. wayne z

    wayne z New Member

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    Yes, you can buy Ryobi weedeaters that have detachable shafts that also take a polesaw and a tiller,snowblower,ect. Check em out at Home Depot!
     
  6. wayne z

    wayne z New Member

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    You can find the polesaw heads on E-bay pretty cheap. These gearboxes are ready made to take a sprocket!
     
  7. cannonball2

    cannonball2 Active Member

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    You should be able to come up with an inframe with this set up.
     
  8. charles.paskell

    charles.paskell New Member

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    This is a great idea, run with it.

    If they build it, they will ride. lol
     
  9. wayne z

    wayne z New Member

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    And they have a strong mounting point from the saw bar mount., Dang I gotta find one of these.
     
  10. wayne z

    wayne z New Member

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    I have already posted pics of a real nice FD with a weedeater motor and gearbox, on page6 of the DIY threads named "A Strange way to mount a string trimmer" go to last post to see a pic. Explanations and more pics in that thread.
    Don't know how to cross link pics or posts. I wish this site would let us re post pics. Lotta People go un-informed about stuff cuz of this.
     
  11. cannonball2

    cannonball2 Active Member

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  12. wayne z

    wayne z New Member

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  13. Dan

    Dan Staff
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    Great thought Ferball. Would really help folks on a tight budget.

    Was thinking today about a mounting kit, sort of a big erector set so one could make in-frame, rack or front mounts. Would be relatively inexpensive to produce and be all bolt and go. So could be dismantled for new builds. Have a pre-drilled engine plate with the bolt pattern for the widely used engines. Honda/clone (Clonda), HF predator common sized WWs.


    An inexpensive kit would be a great gift to the world. A MB is whole lotta folk's main or only form of transportation. If there is any way I could be of help with your project, just let me know. Read twice today about members here who when their MBs failed, they were not in a position cash wise to fix em and were really stuck. Could be the difference between folks getting to work, doc. and to the store etc.

    Not sure if it is still true or not but used to be people in Europe were having problems getting China girl kits. So could be a market for you as the engines could be bought locally and cheaply as they are already shipped there or produced locally. So providing all the accouterments for a MB would be welcomed, me thinks.

    But again, really great thought.

    .flg.
     
  14. rohmell

    rohmell Active Member

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    Will the 1/4 inch flexshaft be able to handle the torque? I have seen some of the 1/4 inch squares on the centrifugal clutch become round and slip on the shaft.
    Speaking about gearboxes, many people buy the Harbor Freight auger just for the motor to use on friction drives, etc, but that auger gearbox has an output of 150 RPM at full speed. I was wondering if anyone has considered using the output to drive a chainring sprocket, so the gearbox would do the turning instead of pedaling?
     
    #14 rohmell, Aug 3, 2011
    Last edited: Aug 4, 2011
  15. Dan

    Dan Staff
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    Gave me an idea Rohmel. DIY flex shafts. Drain cleaning cables come in many sizes and can buy couplers for them with threaded bolts.

    I have been trying to figure out for years how to or where to buy a 90* worm gear to alow for using a vertical shaft lawn mower replacement engine for a rack mount. They are cheap and low profile. Would make for a great rack-mount IMHO.

    Make it like a boat/ships stuffing box with just some pipe with a zerk fitting. Would be a lot of friction so heat might be an issue. Maybe bearings on either end?

    If this works will call it a "Rohmel gear"

    The drain cleaning cables are pretty much just long, tightly wound springs in a right-hand "lay". They are used to cut roots out of sewers and are amazingly strong. I have cut some huge root stalks out of pipes with em so have great hope for this idea.

    Thanks Mon!

    .flg.
     
  16. ferball

    ferball New Member

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    Waynez setup is along the lines I was thinking. The engine can be swapped out at will with out effecting the drive setup. I am sure a similar chain or belt drive set up could be fabbed up using the gearbox as the drive source.

    I think the 1/4 flex shaft would hold up fine given that we are using the engines they were designed for. Even if they did not hold up, the idea behind the kit is that the engine is "expendable" the only thing that really needs to last is the drive assembly. everything else can come from a recycled weed wacker on e-bay.
     
  17. cannonball2

    cannonball2 Active Member

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    If you are gonna run the straight shaft head the you can just scrounge a sold shaft, and grind the 4 flats carefully in the ends, done it many time on projects and putting to gether junk to use for myself.
     
  18. wayne z

    wayne z New Member

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    I used a short piece of 1/4" keystock, grinded to fit
     
    #18 wayne z, Aug 4, 2011
    Last edited: Aug 4, 2011
  19. momentummotorgroup

    momentummotorgroup New Member

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    ""The Ice King is lame because he hides his ninja love"
    -Finn the Human "

    HAHAHAH!!! That cartoon is soooo not for kids.. So good..
     
  20. cannonball2

    cannonball2 Active Member

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    Done that too Wayne on a mini tiller I fixed up for the wifes gardening experiment worked great and was easier. Was thinking if the engine was further away. Still like the idea of the motor foward(inframe), but looks like the only way to tweek it to fit is to use a flex shaft. I think its up to the job if a good quality unit. I cant tell you how many trimmers came into the shop with a steel brush blade cobbled on to a flex shaft. The shaft wind up was terrible on accel/decel. Yet they hung in there somehow. BishopL seems to be doing fine with the little Homey.
     

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