Folding bike with happy time and a jack shaft kit?

Backhillbiker

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I want to build a folding bike with a 66cc 2 stroke and a shift kit. Does anyone think i can mount the engine and shift kit on a montague paratrooper frame, maybe with a little welding? Ive seen a paratrooper with a rack mounted friction drive, and i saw a dahon or something similar with 20in wheels with a regular HT setup, but i want the shift kit
 
This is an electric drive. Goes faster than I feel safe and stable.
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I like the gears, although the deraileur tension wheel is a bit too low for off-road riding.

This electric is more stable but is a single speed and only does about 15mph. I is an excellent city bike:
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I have a 3 speed hub shifter Dahon as well. Well built bike. I've had the same thoughts as you, to gasify it!
The Montague is an interesting bike. I don't think it would be very hard to motify.
paratrooperlg2012.jpg
 
Thank you for the reply! Ive seen the bikes in your pictures, ive been scanning this website for information the past three days, you are a very active member Steve. Thank you for all the help you have given to the community! Anyway, i have downloaded quite a few pictures of people off this forum of folding bikes with motors. I already have a few plans for bike builds in my head. I built my first HT motor on a scrappy bike and now im addicted. My dream build right now is a folding mountain bike with gears and a light engine that can be ridden with or without engine power decently. Electric is cool but its not for me, i like mechical tinkering and the price/performance ratio. I want something i can put in the trunk of my car and go ride a trail, and also i think its a cool idea to always have spare motorized transport wherever you go. One other build I want to look into is a grubee gas tank frame (undecided on if id want a 2 stroke or 4 stroke). There are some nice looking bikes on here, good inspiration!
 
ive tried looking into this a couple of times. i also like the motorized folding bike concept for the ability to carry it in a trunk or rear seat, small wheel size (20"), and ease of riding for almost all height riders. I am almost definitely looking into a 4-stroke friction drive versus a 2-stroke or shift kit.

the issue to resolve for the friction drive is proper fit with the smaller frame and different frame mounts. for friction drives, the roller should sit slightly forward of the middle of the tire for maximum performance. i am not sure if the 26" friction drive kits have allowances for the smaller folding bike frames or can be modded to fit. i tried emailing Staton friction drive guys but did not get an answer and they pointed me to some $700 kit...

take a look at some old videos of guys with friction drive kits on 20" folding bikes.


 
Friction drive is the most common i have seen attatched to a folding bike, but i want the ability to immediately cut the engine and pedal. As far as i understand friction and belts cant do this quickly. I have considered a rack mount instead of a frame mount but im not sure how hard it would be to rig up a HT motor with a shift kit to the rack instead of frame.
 
Friction drive is the most common i have seen attatched to a folding bike, but i want the ability to immediately cut the engine and pedal. As far as i understand friction and belts cant do this quickly. I have considered a rack mount instead of a frame mount but im not sure how hard it would be to rig up a HT motor with a shift kit to the rack instead of frame.

well if you know the proper friction kit that will fit a 20" folding bike then let me know. haHAA :D

the second video the guy has a custom engage lever at the front of the bike so he can engage and disengage the motor.
 
Friction drive is the most common i have seen attatched to a folding bike, but i want the ability to immediately cut the engine and pedal. As far as i understand friction and belts cant do this quickly. I have considered a rack mount instead of a frame mount but im not sure how hard it would be to rig up a HT motor with a shift kit to the rack instead of frame.
The belt drive on the lawnmower has a easy to use engage and disengage lever, and I don't have to get off to throw it..

Belts can be made to disengage easily, usually by pushing or pulling a pulley against the belt to tighten it against the drive wheel. When moved away it becomes slack and the belt doesn't engage well enough like that and it slips on the wheels..
 
Thank ya'll for telling me about this belt disengage! That will be something i look into when its time to make a small folder with 20in wheels. But for a larger folding mountain bike i think the chain drive with shift kit is still more ideal for hitting trails. The belt would definitely work for around town kinda stuff.
 
Electric seems like a good option. The smaller the bike the more hassle a gas engine is, IMHO. I mean for practical use.
 
Electric seems like a good option. The smaller the bike the more hassle a gas engine is, IMHO. I mean for practical use.
This is true, one of the great downfalls of the China girl special is she is very large and ugly, and over weight. Those fantastic Korean electric girls can practically fit in your pocket.

Indeed, the smaller the bicycle the more likely an electric motor would be a better choice.
 
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