Sprockets and such. Second noob post of the day!

R

RatFink608

New Member
Ok, so I've never built a chain driven bike before and I have a question concerning the sprockets on the rear wheel. How can I keep the pedals attached and functional while adding another sprocket to the back wheel for the engine to drive? If I just slap another sprocket on it, It would still pedal, but I don't want the pedals to be driven by the motor once I'm using the throttle....if that makes sense... I need some way to keep the pedals separate from the engine drive. So far, I can't think of anything that I can do to do this. Any help AT ALL will be greatly appreciated :-||
 
Think of it this way. You pedal, the bike rolls and then you stop pedaling but the bike continues to roll and the pedals don't move. That's what happens with engine power. As long as the clutch is disengaged the bike will roll normally with just a little drag from the chain/sprockets and clutch cross shaft.
Either a manual or a centrifugal clutch disengeges the rear wheel from the engine. The rear hub is a free wheel design and unless you are using a shift kit there is no connection between the engine and the pedals. If you've never driven a manual transmission car then it will take a little practice to master but it will become easy quickly.

If you are installing an engine kit this thread might be in the wrong section.

Tom
 
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Ok, thanks. I'm using a chainsaw engine, not a kit. So I can just put another sprocket on the back wheel and it shouldn't keep moving the pedals while the bike accelerates?
 
All the chainsaws that I can think of have the sprocket on the same side as the pedal drive chain, and do not have the gearing to suit, you may have a little trouble with this idea?
 
Theon said:
All the chainsaws that I can think of have the sprocket on the same side as the pedal drive chain, and do not have the gearing to suit, you may have a little trouble with this idea?
Click to expand...
Ditto:
It won't be a bolt-on application. You'll have to find some way to disengage the engine from the rear sprocket. Attaching an engine to a bicycle that isn't meant to be mounted on or drive a bike takes some mechanical experience and some engineering.

Good luck but others have done it many times. Keep reading the DYI threads and you'll get there.

Tom
 
Well, I got to looking around on Dax's website, and I found a steel freewheel hub. I think that is what I'm looking for but I'm not sure. it looks like it will keep the engine drive and pedals separate but still functional on their own. Am I correct? I just want to make sure before spending $$! I'm also thinking about just buying an 80cc kit. seems a whole lot easier than trying to mess with a 42cc chainsaw motor that isn't built for bikes anyway.
 
It depends on your mechanical talents and the tools you have or have access to.
A kit can be installed with a minimum of either but only experience will provide you with a safe reliable motorized bicycle.

The kits, though easily installed still need an understanding of basic mechanical theory to be successful. Roller chain drive and sprocket alignment is an area that is often misunderstood by a new builder. A basic grasp of electrical connections and fastener (nuts & bolts) use is also essential. (don't overtighten them)

I suggest a kit for your first effort as opposed to a DYI project. It will provide you with experience and there is a world of information here to draw from if/when you need it.

Good luck and let us know what you decide to do.

Tom
 
Thanks for the tips guys. I think I'll probably go for a kit. I have a pretty good garage setup and am good at mechanical work. I think I'll probably go with a kit though... I'd just rather spend more time riding the thing than working on it and buying new parts. Are DAX's 2 stroke kits any good? I'm looking into one of those. Also, does anyone know about how much they cost? I didn't see a price on the website.
 
RatFink608 said:
Thanks for the tips guys. I think I'll probably go for a kit. I have a pretty good garage setup and am good at mechanical work. I think I'll probably go with a kit though... I'd just rather spend more time riding the thing than working on it and buying new parts. Are DAX's 2 stroke kits any good? I'm looking into one of those. Also, does anyone know about how much they cost? I didn't see a price on the website.
Click to expand...

Friction drive that beyotch...
Rear mount and swap the sprocket for a roller of sorts...build a lift and rock out
 
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