different frames to use for HT engine

[mikesova]

I was working on a1950's schwinn cruiser that I had planned to put an 80cc HT engine on, but when trying to install it, I found that the crank was too narrow and would hit the sides of the engine. So i'm on the lookout for a new bike to mount it on. I have a mountain bike that I could use, but it has bigger tubes and I just think a mountain bike would be too complicated with all the shifters, etc. so I was wondering about using an older "road bike" frame to motorize w/ small skinny tires? how do these work w/ the engine?

or what about the lowrider style bicycles like this:

are these too small for mounting the engine? I assume they are, but I thought I'd ask.

thanks.

 

[mikesova]

i found an answer to the second part...

http://motorbicycling.com/f31/old-schwinn-stingray-style-frame-will-3805.html

 

[HoughMade]

There is also the option of a wider crank which would be a $20 solution which would allow you to keep the family bike and your original plan.

There is a special wide one-piece crank made for 4 stroke kits, but you would probably be able to get away with what would now be sold as a standard width crank which is wider than your present crank. Check someplace like Aztlan or Bikepartsusa.

 

[mikesova]

There is also the option of a wider crank which would be a $20 solution which would allow you to keep the family bike and your original plan.

There is a special wide one-piece crank made for 4 stroke kits, but you would probably be able to get away with what would now be sold as a standard width crank which is wider than your present crank. Check someplace like Aztlan or Bikepartsusa.

from what I've read it's not just changing the crank, i'd have to change the chain rings too plus another thing. I don't totally understand it. It's no big deal, I enjoyed rebuilding grandpa's bike and I can just do it again with a bike that the engine will fit on. I kind of like the looks of those lowrider bikes. They would have a slightly lower center of gravity.

Here's what somebody else said:

"ok, you have this: http://www.sheldonbrown.com/opc.html

You need this: http://sheldonbrown.com/harris/opc.html (scroll down to Bulletproof American-to-Euro Conversion kit)

Then you just need a bottom bracket, and a crank..
Get a gereric Shimano UN-53BB with a wide spindle, and then a cheap Square Taper crankset.

Done."

what would that cost to get all that?

 

[HoughMade]

I've done this- multiple times. The original sprocket is bolted to the crank- it can be unbolted and put on a new one. A standard one piece crank is pretty universal. The extra wide cranks use an octagon sprocket, but I think they come with one. Otherwise, one piece cranks are standard with the big hole in the middle, small hole to the side. No modification of the bottom bracket is necessary unless you decide to go to a 2 piece crank....but why?

It's just an option. Good luck.

 

[mikesova]

hmm. ok. i'll check it out. anybody got a link to where I could purchase that?

 

[JE]

sickbikeparts.com might have the crank you need.

 

[OSCAR383]

that was my bike pictured in the link to the other site. and i used the stock crank it did rub the clutch side on the engine . when i installed the smaller crank sprocket i moved one the the washers on the crank to the other side and it clears its close but it clears