Moped/motor bike project

Discussion in 'Motorized Bicycle General Discussion' started by sseisup, Jan 1, 2010.

  1. sseisup

    sseisup New Member

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    I got an old moped with no rims and a dead motor. I came across a free 20" bicycle and cut it up to bolt the pedals in. I don't want to cut the frame but can't afford moped parts so I'm looking at putting on one of those Ebay 80cc kits on the thing. I plan on building some kind of bolt on frame to hold the motor just behind the front tire if it looks like it will fit once I can afford a motor kit. Then I have to come up with some kind of front break. It's the dead of winter, 2 feet of snow here, so I thought this would be a fun project. Now if only I wasn't poor. Any thoughts?

    [​IMG]

    :-||
     
  2. KClowlife

    KClowlife New Member

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    Looks pretty sweet to me. With that rear rack, seems like you might even be able to put one of those Honda 4 strokes on the back if you wanted. But I hear those are more expensive than the normal ones, so may not fit your budget.

    I don't have one myself yet. So I'm watching others projects with interest.
     
  3. professor

    professor New Member

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    It would be easier to can the moped idea and just put the motor kit on a bike.

    1) how do you get the drive chain to the rear wheel- looks like the frame might be in the way?
    2) you need to build a loop for the motor mounts to attach the engine.

    It WOULD be nice to have the suspension that the moped affords. If you can do one and two you are golden.
     
  4. Nougat

    Nougat New Member

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    Part out the moped at mopedarmy.com, and buy a proper bicycle and engine kit.

    A bicycle engine kit isn't going to be easy to fit into that frame. It looks like a Puch, and you could probably get a used engine and proper wheels for it for less than you'd spend on a bicycle engine kit - again, used, mopedarmy.com. Puch parts are plentiful and cheap.

    Edit: I should also mention that that moped frame is a whole lot heavier than a bicycle frame, and the pedal cranks are super short. Pedaling it is like riding a clown bike. They didn't ever intend for those machines to actually be pedaled; it was just to fall within the legal territory of "moped." They are actually small motorcycles.

    So, even if you were to get a bike engine kit on it, you would burn through the clutch in no time (trying to take off from a start, because you can't pedal it up to speed), and the finished machine would not be fast enough to get out of its own way. For me, that's neither a safe enough nor satisfying enough end product.
     
    #4 Nougat, Jan 1, 2010
    Last edited: Jan 1, 2010
  5. Nashville Kat

    Nashville Kat Active Member

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    This is a 20" bike right? Not a moped? It's kinds wild. I might re-sell it on ebay.

    Yeah, it's hard to judge frame clearances. Why not just a motor in the middle? Use a smal sprocket to compensate for the small wheels.

    Something more radical might be to get a three wheel hub, shorten the axle and offset the motor to one side, to make a tricycle with two close wheels in the back- maybe a tank, or staorage bin on the other side?

    I'd get some nice alloy BMX rims either way. Annodized alloy is always popular: lightweight, and enhances resale value besides looking great.
     
  6. Nougat

    Nougat New Member

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    The machine in the picture is a Puch moped frame with 20" bicycle wheels on it. The mopeds came with wheels about the same size, although wider and sturdier, and with drum brakes front and rear.
     
  7. sseisup

    sseisup New Member

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    The moped is an 1984 tomos silver bullet, but it shares many parts with Punch. The moped army isn't much help as I live in Minnesota and they don't have much of a presence here. I could ship the parts but money being an issue and all I figured doing it as a 20" bike with suspension would be a cheap way to get it riding until I can afford the parts as nothing last forever anyway. The main thing is to not ruin the moped parts I have while trying to get it going. I have other bikes I could put a motor in, but I really think this would be fun. I was going to put a smaller sprocket on but I think the extra power is worth the lower speed to extend the clutch life as has been pointed out might be an issue. I am considering changing the sprockets and pedals so I can get the thing up to speed. There is a ton of help for bicycles around here, even free bicycle parts but every time I mention adding a motor people say "why don't you just pedal?"

    This thing is a three way love child...

    .flg.
     
  8. Cannonfish

    Cannonfish New Member

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    Sseisup, you have a cool project in mind. Although if inexpensiveness is the goal, I'd think that either a straight-up MB kit build (no expensive and/or time-consuming adaptations required) would definitely be cheaper, followed maybe by a used moped.

    Adapting transportation devices to something they weren't intended for is a heck of a lot of fun, but (at least for me) always ends up being more expensive and less practical than I thought.

    Having said that, I hope you follow through with it - cause I want to hear about it and see the pics! :)
     
  9. Nougat

    Nougat New Member

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    Ah Tomos, okay - you can still get all kinds of parts for those, too. You said the motor is dead; how dead is it? Frozen solid or does it turn? If it turns, and if the piston and cylinder look decent, you can make it go.
     
  10. sseisup

    sseisup New Member

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    The motor was seized and covered in RTV silicone. I had to hammer the piston out because it was siliconed to the walls. The cylinder walls are shot (rusty pitted), the rings broke and there isn't a gasket in the whole motor. I left the moped at my parents and my dad says he gave away my rims and tires to a guy so he could make a trailer. The cables and wires are all shot from sitting outside. I got the front shocks to work but the rear ones are frozen. I recovered the seat with a leather jacket from the thrift store for $4. I rewired the lights to a battery and have been riding it as a bicycle (it's not that heavy).

    I love the comment of you could build it cheaper by using just a bike, that being said I hope you finish it. I got quite a smile out of that. It's an interesting thing, I'm glad people are interested. Thanks guys!
     

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