How to add a sprocket on a weed eater shaft

Discussion in 'DIY Home Built Motorized Bicycle (non kit)' started by Jeco, Jan 6, 2011.

  1. Jeco

    Jeco New Member

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    My first weed eater bike project

    Happy new year to all!!

    I have this weed eater bike project I need some help with.

    Got this Homelite Mighty Lite 26cc HLT26CDNB weed eater to put on the rear of fold-able bike I have collecting dust. I thought this homelite model have a clutch in it, unfortunately none, must be an older model as I see the specs online for the HLT26CD having clutch.

    Is it possible to add a clutch on this?

    Anyway, I got the casing removed and found the shaft having a square hole. I will use an HT 10tooth sprocket and 44tooth for the big one. Not sure how the engine will handle this though.

    What tools/method can I use to put the spocket on the shaft? Sorry I am not mechanically inclined :)

    Or will this better with a friction drive setup in regards with the motor power output?

    On this I will use a bike peg I suppose.

    Thanks in advance for the replies guys.

    Jerico
     
    #1 Jeco, Jan 6, 2011
    Last edited: Jan 6, 2011
  2. Jeco

    Jeco New Member

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    Got some slotted angle bars for mounting, I think this will be an easy mount.
    Waiting for the sprockets to be delivered hopefully tomorrow, if not I will do Friction drive setup. Less cost.
     
  3. Erich_870

    Erich_870 New Member

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    Can you post up some pics? I've never heard of a weed whacker that didn't have a clutch, so it would be helpful to see what your engine looks like.

    I built a boat motor out of a Ryobi weed whacker, and it works well, so it would be fun to assist you with your build. :)

    Erich
     
  4. Andyinchville1

    Andyinchville1 Manufacturer/Dealer

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    HI,

    I think you will need more gear reduction than the roughly 4 to one ratio you will end up doing what you are thinking about....

    The little Chinese frame mount 2 strokes (center mounts) have an internal primary reduction of about 4 to one (it's hidden under the clutch cover) THEN they drive to approximately another 4 to 1 reduction (the front sprocket to the rear sprocket)....for a total gearing reduction far beyond your roughly 4 to 1 overall ratio.

    Friction drive will give you a better chance at working faster and easier but it may eat tires more often.

    You could try a jackshaft to get better gearing with a chain drive.

    The smallish displacement of the weed eater engine may hamper performance somewhat tho....BUT then again I was thinking of adapting an R/C Nitro .21 engine (3.5 CC!) for bike use!

    Sounds like an interesting project....Good luck and keep us posted!

    Have fun!

    Andrew
     
  5. happycheapskate

    happycheapskate New Member

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    #5 happycheapskate, Jan 7, 2011
    Last edited: Jan 7, 2011
  6. Dan

    Dan Staff
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    Great find Happy. That's gonna help a whole bunch of folks. TY

    Wackerengines

    .flg.
     
  7. Jeco

    Jeco New Member

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    very nice find indeed happy!

    as suggested by Andrew and some search in youtube, my homelite is now with a bike footpeg for now. The chain and sprocket came a bit late.

    @erich
    it does not have a clutch as seen in the pictures attached. That's how it looked like out from the case, with a small shaft that is now inside the peg.

    On mounting, screws from the casing are a bit small. I'm not sure a similar size bolt/nut will do. Should I make the holes larger for a bigger bolt/nuts?
    I'm afraid the holes will break with the motor and tire's force, or this is strong enough?

    Thanks guys!

    Jeco
     

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    #7 Jeco, Jan 10, 2011
    Last edited: Jan 10, 2011
  8. Erich_870

    Erich_870 New Member

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    Well, you learn something new everyday. How will you start it with the pull cord removed?

    Here's my ryobi clutch

    [​IMG]

    Erich
     
  9. Jeco

    Jeco New Member

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    It'll be a pedal/push start.

    Good that you have a clutch on your ryobi, but some say these kind of motors are better off without the clutch, more power without it.
     
  10. Erich_870

    Erich_870 New Member

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    Funny you mention that they sometimes are better with out a clutch because I had to build a clutch lock-up plate because the clutch was always slipping and over heating.

    [​IMG]

    [​IMG]

    Erich
     
  11. Jeco

    Jeco New Member

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    That's a cool way you did on the clutch. You're doing a chain drive?

    My problem now is mounting the brackets, as you can see in the picture I dont have much to bolt on. If I make the holes bigger I'm afraid it'll break easily in no time at all.
     
  12. Erich_870

    Erich_870 New Member

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    It still uses the straight shaft and gear head at the bottom, but now it's a direct drive.

    [​IMG]

    [​IMG]

    If you can drill out the stock holes and make them thru bolts, that will add strength, but they look like solid mounts right now. They are nice and far apart which will greatly increase your strength. If you compare my ryobi bolt distance to yours, yours is much better for the loading your plan to have.

    Erich
     
  13. Jeco

    Jeco New Member

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    Ingenious use of a whacker man! how fast does it go?
     
  14. Erich_870

    Erich_870 New Member

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    Thanks! My GPS says it does 4.6-4.9 mph. The last test run I made was to find the right running depth. I need to make an anti-ventilation plate to go over the prop, but it will have to wait until spring for testing again.

    Erich
     
  15. happycheapskate

    happycheapskate New Member

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    I remember some 2 cycle boat engines that look like that, which are used in Korea and Vietnam on small boats. (saw them in movies and on discovery channel) They went quite fast. Does anybody know the name of the product? I wonder if the motors can be used on motor bicycles!

    Edit: They can, but they only sell the complete product, at $500-600, and the motors are Kawasakis that you can get elsewhere.

    Here: I'm not sure if this is the brand used in the tv show I saw, but they are ready-made 2 stroke 1 - 4 hp weeder style outboard boat motors

    http://www.smalloutboardmotor.com/
    [​IMG] http://www.smalloutboardmotor.com/images/100_1892.jpg
    Island Hopper brand.

    I wonder if these motors can be found in marine shops, used, like if the fan/shaft parts were busted or they were just unwanted or lost under mechanics liens.

    I made one out of a 2 stroke brush cutter once. I made my own prop from a modified edger blade. It was powerful but it blew up the shaft before I could try it actually on the little fishing boat.

    I emailed them to ask if they can sell only the motor without the prop and boat trolling system.
     
    #15 happycheapskate, Jan 10, 2011
    Last edited: Jan 11, 2011
  16. mekano

    mekano New Member

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    They use any engine they can get and goes from there.
     
  17. Jeco

    Jeco New Member

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    I should change the title on this thread....

    Anyway, I managed to mount the motor using slotted angle bar, made the mounting holes bigger for bigger bolt and nuts.

    On my test drive, the bike is a kid's bike with small crank arms on it. Was not really meant for an adult. It was really hard to pedal. The motor almost started when my legs got the cramps and me catching my breath really hard. I Got so dizzy I can't go for another round, hahaha!

    I will have to put the motor on a bigger bike we have here maybe tomorrow.
     
  18. happycheapskate

    happycheapskate New Member

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    I like the DIY approach. I like recycling. So I think its really awesome if you can find a throw-away or re-sold engine and run it to death on a bike. Looks like a good time. 20 or 25cc engines ought to work ok for cruising after you pedal away, but I wonder why people are surprised that the clutches are weak.

     
  19. Erich_870

    Erich_870 New Member

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    Sorry about taking your thread off topic .bf.

    Erich
     
  20. Jeco

    Jeco New Member

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    My fault actually, my chain drive plan turned to a friction drive. I will have to use the chain and sprockets next project.
     

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