Backazwards build? Start with 65cc moto, chop build into mtb? Does anybody do this?

forties

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I would love to try something like this... is this even possible?

1. Buy used kx65
2. Sell off body, swinging arm, fork, wheels and other bit you don't need.
3. add sweet dh mtb fork, custom crank setup, custom hardtail rear.

I haven't really thought this through deeply yet.. but I think the cranks gonna be the difficulty.
 
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forties

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Weight could be an issue too. I have never had a 65.

Looking at the frames on the "motoped" style moped stuff got me thinking about this backwards approach.
 
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Tony01

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I’ve done both backwards builds; hardtailing an old dirt bike, and swinging an old schwinn cruiser. My best advice is leave it the way it is and only modify the power plant, wheels, seat subframe, etc. It looks like it has 14” rims? Probably about 20” OD, I bet if you go to big wheels, lengthen the swingarm or fab a new one, it would look cool... lot of work tho...
 

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indian22

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One of the great benefits of this forum is you can actually see different versions of "your" concept so you don't go into the work blind. Tony's great builds shown here present graphic evidence of how one man's quite different designs worked using the concepts that you're contemplating. I too used a small vintage motorcycle frame style (Simplex) as a base to mount a Honda clone 5 speed. Your imagination coupled with your skill sets or with those possessed by others can result in a great bike. Innovation not repetition of another's work creates infinite possibilities of design and performance.

Hope you enjoy the process though hard work it's fun and satisfying.

Rick C.

resize simplex.jpg
 

indian22

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Thanks Forties remember that it's your build and your concept and design. Categorizing right or wrong are absolute death to innovation of design. Only you actually have a vote that matters in this area. Matters of safety however do matter and are pretty well developed for bikes with or without motors. These things need to be pointed out when a builder is constructing an inherently unsafe bike.

Some designs are really expensive to build and require skill sets that not all posses but which can be learned, but those which have skills can and do produce some cool stuff. I've been asked which is my favorite all time forum build and my answer is, it hasn't been built yet. So build some cool stuff and that only happens when you build that which pleases you.

Rick C.
 

wheelbender6

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I would think that forties' approach would only work on a motor bike with a single cradle frame. Adding a pedal crankset to a double cradle frame sounds too difficult.
 

indian22

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It is hard but that's what I did with the Simplex (shown in a previous post, this thread) frame design which consists of duplex tubes and I added a pedal bracket, which no Simplex ever had a pedal function. I cut all the original frame tubes from the head tube and built a much longer and taller frame from 1" DOM tube which was necessary to house and support the large integral 5 speed/engine case and the added weight/power. It's performed well for several years and lots of miles.

Rick C.
 
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forties

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What cranks did you guys use? Wide ones yeah?

Thanks Forties remember that it's your build and your concept and design. Categorizing right or wrong are absolute death to innovation of design.
Well not looking to do anything complex, just want a fun mini moped. Thing is, legal or not, the moto frame combined with a small wheel "look" may be asking to get pulled over. The 26" wheel look is your more typical bicycle image.. still 50/50 on if this mini thing is a good idea. Anyways some junk I have gathered so far..

crashed moto with bent front end and trashed bodywork
new bicycle triple tree style front end with disc brake
20" front disc bicycle wheel, 20" rear disc wheel.
steel head tube, and donor steel bmx frame for the rear
 
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forties

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I might scrap the 20" thing and just do the normal 26" or 29" wheels. But 20 might make geometry easier coming from small wheels on the mini frame. Car transport is a little easier too.

I should just scrap this idea and pull the motor and stick it in a mountain bike... :p

Idea of a moped legal neighborhood cruiser that looks like a mini motocrosser is appealing though.
 
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