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DIY Home Built Motorized Bicycle (non kit) Post all about your home built rides here. Weedwacker motors, lawn mower engines ect. This area is for non kit builds


freewheel crank

Post all about your home built rides here. Weedwacker motors, lawn mower engines ect. This area is for non kit builds


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  #1  
Old 11-12-2008, 08:55 PM
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Talking freewheel crank

So I got to thinking about building my winter build and looking at a jackshaft kit. I tell you if money weren't so tight I'd just buy one of Pablo's kits. But I was thinking how can I get that front crank to freewheel?

I was looking through c list and I saw a tandem. DUH! The rear crank for the stoker is a freewheel crank with 2 sprockets. When the guy in front pedals the guy in the rear doesn't have to but the freewheel on a tandem rotates and transfers the power to thew rear- freewheeling.

So the real question is where do I find a cheap stoker set of cranks? I looked at all the bike part sites and the cheapest I found them is $105. For that price I could save up the $$$ to buy the Pablo set.

Anyone know where to get these cheap, used or something?

And better yet has anyone tried this so that they can keep the pedals but use a jackshaft?
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Old 11-12-2008, 11:15 PM
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Default Re: freewheel crank

I am looking to build a Mountain Bike that I can use off road, on official bike trails. It needs to be lite and still look like a Mountain Bike. I was thinking that it would be best if I were to use a freewheel main crank. I would like to have the engine over the rear wheel and fetch the chain down to the main crank. with a freewheel on the engine I would be able to operate the bike with or without the engine running. As a mater of fact I would like to start and stop the engine while still in motion. It would then be able to use the gears to propel the bike in any condition of road. Have fun, Dave
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Old 11-13-2008, 06:48 AM
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Default Re: freewheel crank

I think a clutch would solve the issue on the engine. But I agree withyou if you are running the engine chain to the main crank you need a freewheel up there.

The real question is where do you get one cheap? New or used? Ebay and craigslist are a dead end.

I put an ad on craigslist to see what I get but I haven't had much luck searching for parts like that before so we'll see what I get. I might call and chat with my local guys.
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Old 11-13-2008, 08:05 AM
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Default Re: freewheel crank

Ah the joy of friction drive lol... Just put the engine in a saddle bag and drop it when you need it lol....

All that other stuff is way too complicated for an ole city boy..
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Old 11-13-2008, 08:39 AM
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Default Re: freewheel crank

Honestly I think that's where some of the expense of Pablo's kit comes in. Those things just aren't common enough to be cheap. You could look into a bicycle/parts recycler maybe...
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Old 11-13-2008, 09:38 AM
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Default Re: freewheel crank

I think the more you search and investigate the more you will soon realize that the price we charge for our kits is extremely reasonable. You just can't put all those pieces together for the price we are selling it for, especially if you factor in any labor and fabrication time. Just an example, so you need a sprocket, it has to fit a bike chain or the 415 chain. Guess what they don't make one. So you will have to find a similar one, and you maybe are able to get it for $10-$15. Then you will have to send it to a machine shop to have it machined, there goes another $30 for them to machine it. So now your $10 sprocket is $40. If you continue on that path for most of the parts necessary you will be well over $200 very quickly. Not trying to discourage or practice salesmanship just stating the facts. We have actually provided technical assistance to many that wanted to do their own and they almost all ended up buying a kit because in the end it was cheaper.
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Old 11-13-2008, 06:32 PM
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Default Re: freewheel crank

ghost as I've been doing the research the one thing that sets me back is the price of the crank. the rest of it not so much.

has anyone used your kit with a Weed whacker?
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Old 11-13-2008, 07:19 PM
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Default Re: freewheel crank

The kit as it is designed works only with the China 2 strokes, the way it all mounts together will not work for any other engine. We are working on a kit for the frame mount 4 stroke Honda and Huasheng but that will be a little while.
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Old 11-13-2008, 09:57 PM
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Default Re: freewheel crank

I think if I were to start the build I would just use Ghost0's outfit, like he said it would cost more to start buying each piece. I like the friction simplicity but tired of the slipping. For off road with mud and the like it would never keep up. I still might work on my dual roller outfit and see how that would work. Larger rollers and gear them down with sprockets. The larger rollers get better grip. Have fun, Dave
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Old 11-13-2008, 11:41 PM
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Default Re: freewheel crank

I have been house bound today and will be tomorrow rain. i would have to plan to have days like this if I did not have a wife who still drives.
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