help! mounting motor higher to clear bike sprocket

Discussion in 'Mounting Techniques for Bicycle Motors' started by grim650, Dec 16, 2014.

  1. grim650

    grim650 New Member

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    I have a 80cc motor I've purchased from venice motorbike. When I put motor on it hits the bike sprocket be for it can slide into place:-||. The sprocket is to big. I read about getting longer stus for the mottor and using motor mounts but also read not to use motor mounts. Are there any other options or ways of mounting the motor higher ?and so it stretches to each part of the bike frame.
    if anybody wants to post pics of how they macgyvered there motor on feel free! I'm stumped
     
  2. grim650

    grim650 New Member

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    Here is a pic of the bike I'm useing. It's a old schwinn cruiser
     

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  3. maniac57

    maniac57 Old, Fat, and still faster than you

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    The easy fix is simply use a smaller front sprocket. All single speed sprockets interchange so it's easy to find another, smaller gear. Makes it easier to pedal as well.
    I used one from a kidde bike for clearance on my WCC chopper build...found the bike free on the curb. One of the 12" kids bikes, Tonka or Transformers or something.
     
  4. bluegoatwoods

    bluegoatwoods Active Member

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    I've used a smaller sprocket, too. It works and it makes starting from a stop a bit less clumsy.

    But you might run into another problem. If you keep that engine low, with the front mount attached to that curved portion of your downtube, then you might find that the curve, a few inches above the motor mount, interferes with your exhaust.

    ..............you know.......I think I have a photo of a way to get around this. It's one of my older bikes. I had the problem that I just described. I'll look and see if I can find it. Then I'll be back.
     
  5. bluegoatwoods

    bluegoatwoods Active Member

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    Here you go.

    002.jpg

    The front mount adapter that I made was two muffler clamps with a bridge in between.

    I'll digress just a bit here to cover something important. You'll notice that I also wrapped that downtube in neoprene rubber. The consensus around here is pretty strongly toward the position that one should not (repeat, Not) use motor mount dampeners. There's some good reasons for this. I won't fill this thread with that. It can be found in other threads if you're interested.

    I went ahead and did it, in this case, because I wanted to make sure that I filled the hole completely. I also didn't feel that it made much difference, again in this case, because I knew that I was going to be able to tighten those muffler clamps very solidly. But in general I agree with the notion that one shouldn't do it. So I recommend not doing it.

    Anyway......back to the point........

    The muffler clamps are bridged by a piece of steel that measured, I think,
    1 1/4 or 1 1/2 wide by 1/8 thick. The actual motor mount studs passed through a piece of steel of the same dimensions that was mounted cross-wise to the muffler clamp bridge.

    Now let me warn you against a mistake that I made. You can picture the place where the cross crosses the bridge. It's a square, right? 1 1/4 or 1 1/2 inches across.

    I drilled one hole in the center of that square in order to bolt the cross to the bridge. It didn't seem like a problem. Until I ran the bike and found that the engine was actually able to pivot on that one point and lean over. That's bad. Causes all sorts of troubles. I shoulda' seen it coming. But I was thinking about other things.

    I repaired that by sneaking in under there and adding a couple of small struts to stiffen that assembly.

    But a much better way would be for you to, instead of drilling one hole in the center of that square, drill four holes near the corners. That engine won't pivot on that.

    001.jpg

    It was actually quite a good motor mount once I got the pivot problem sorted out. I've forgotten how much it raised my motor. Maybe you can get an idea from these pics. But it seems to me that it was well over an inch. I doubt if it was two inches. Somewhere in between, probably.
     
  6. bluegoatwoods

    bluegoatwoods Active Member

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    It gets better! I've still got the remains of that motor mount!

    01.jpg

    It looks like I used a few leather strips in there as well. I'd forgotten that. But I kinda remember it now. And I know why. I didn't want the edges of those muffler clamps 'biting' into the surface of my frame.

    02.jpg

    Maybe this'll help you out. It's cheap enough, not difficult and it'll certainly raise your engine.
     
  7. fatdaddy

    fatdaddy New Member

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    Just get the large mount U-bolt kit. or make one yourself. It holds the engine up out of the downtube slot on the engine and will give you more room. Try putting a flat plate across the front mount and see if it raises it enough. unscrew the front studs and use anything flat across the front of the engine where a plate would bolt to and check for clearence.
    fatdaddy.
    warning: They sell a large frame kit that wants you to drill a hole in yer frame. DO NOT get that one, NEVER drill a hole to mount yer engine. It'll crack yer frame.
    use one like this instead
    http://www.ebay.com/itm/U-Bolt-Engi...138?pt=US_Bicycles_Frames&hash=item43cf77514a
     
    #7 fatdaddy, Dec 18, 2014
    Last edited: Dec 18, 2014
  8. Commander Billypool

    Commander Billypool New Member

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    Yeah got an old bike too, The idea is making the bike worthy of the efforts to get around the block here. Your options are don't or do includes mounting a 3 speed or greater with a roller or disk brake attached to the wheel or hub. Remember straight wheels are a must on these. Mine works with the sick bike jack shaft but you may find less expensive shifting kits with motor mounts this kit featured was difficult to assemble so keep it in mind you are going to be a hour or two without question if you get there. Anyway the bike you are working on should likely be set aside for one more suitable try to set one up with replacing an engine easily in mind that's my view on it mine is likely going to be rarely used but it has what most of them do more or less .
     

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  9. xlander

    xlander New Member

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    Are you talking about an 80cc 2 stroke?
     
  10. fatdaddy

    fatdaddy New Member

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    Prolly is xlander, I can't really think of any 80CC 4 stroke bicycle engines, Can you?
    fatdaddy.usflg
     
  11. KCvale

    KCvale Well-Known Member

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    There is not any 80cc 2-strokes either, they are 66cc.

    Jut get a http://sickbikeparts.com front mount that fits you downtube.
    It comes with bolts and spacers and the muffler clamp and you can space the heck out of mount with ease.

    [​IMG]

    Just make sure your rear mount hits your seat post at a 90, adjust everything from there as that will be where all your force is.
     
  12. fatdaddy

    fatdaddy New Member

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    66/80cc depends on where yer standing at the time. In the US we only measure the cylinder itself. in other countries, ie China, they include the head dome. Which WOULD make it closer to 80cc. Most everyone knows if ya say 80cc that you mean the 66/80cc engine.
    fatdaddy.
     
  13. KCvale

    KCvale Well-Known Member

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    Displacement is stroke x bore, period.
     
  14. xlander

    xlander New Member

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    They are considered 80cc by the Chinese manufacturers that make them because they use a different area of measurement.

    The reason I asked is because finding help and solutions on a forum helps if the post is in the right section. This is the 4 stroke section. Which means more help would be in the 2 stroke section. Also anytime looking for a similar 2 stroke issue wouldn't be looking in this section.

    Not trying to get all moderator notzi but it makes sense to move this to the appropriate place.
     
  15. Jon D Montgomery

    Jon D Montgomery New Member

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    I need a way to get the motor mounted. Way too far to the front post. Are there any pre made mounts on the market for the1937 Columbia bikes or do I need to fudge it into position?
     

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