Two speed concept.

[Mike St]

Here's what to do: buy a 4 stroke 35cc lifan from
home depot. It's a good engine for about $120. It
has a clutch that fit up to various drives.

 

[2speedboi]

Nice job!
Have you tried deep sockets in assorted lengths as rollers?
Or Staton's rollers?

I've thought about Stanton. The Diablo sanding belt is looking good after 30 miles but time will tell!

 

[2speedboi]

I think you would have interest and maybe it could
be patented but it would not have commercial potential
unless it fitted on the rear tire.

I personally prefer the front, but yes 100% a rear mount would do well.
A few people have sparked interest just driving it around.

That lifan engine looks decent and I have thought about it...

Next step is two speed belt drive.

 

[Cavity]

Really cool gearbox!

However, it's not a two speed FRICTION drive. I saw a #25 or 35 chain. Not that it couldn't be used and modified.

According to my design, in theory it can mount the rear, a new mount bracket and a linked shifting lever from the back should do the trick. I will be moving it to the rear of the bike once I figure out different support brackets to use.

I have been ignoring the bill and by parts as I go and make adjustments and changes. I have over 500 into it with trial and error, I think it can be done for 300, not including engine.

I'll run out and grab a video. Low range is out of service because my reduction is so low. But I'll see what I can do..

With $500+ into it, why not just purchase a 50cc engine with friction drive kit & midsize roller originally? ...it would've been good for cruising, and climbing hills.
Or, do you just enjoy the tinkering and engineering? Regardless, I like your idea.

 

[Mike St]

He has a good idea. A 50 cc engine unless it is the GX50 is too
heavy. With his idea a lighter 35cc could provide real torque
in a lower gear. Go for it!

 

[2speedboi]

With $500+ into it, why not just purchase a 50cc engine with friction drive kit & midsize roller originally? ...it would've been good for cruising, and climbing hills.
Or, do you just enjoy the tinkering and engineering? Regardless, I like your idea.

A few reasons why I am building;

Two speeds, for serious torque for keeping power while under more demand. I would like to build a commuter that can tackle all these ups and downs.

Legally a moped is a moterised vehicle over 30cc In WA state, mine is a motor assisted bike with 27.5cc. from my understanding

 

[5-7HEAVEN]

The concept might be simpler, but more difficult to implement.
Dual siamesed pulleys are common, maybe not in the size you need. What you have to do is
find the smallest drive pulleys and the largest driven ones.
The hard part is attaining the correct gear ratio. You might be shooting for 18.75:1. Doing so with one driver and one driven pulley? Using a 1" pulley, you'd need an 18" rear pulley. Using a second 1" drive pulley and a 15" pulley would get you 15:1 gearing.However, fitting 2 large pulleys on your rear wheel seems impossible.
What you'd need is a jackshaft to mitigate the use of a single rear wheel pulley and twin pulleys at the engine.

Let's see you invent this for the rear tire, not
the front.

Modifying this invention from front to rear tire would be easier and cheaper than modifying the uber scoot's invention to fit an mb.

 

[darwin]

Too bad a simple light weight CVT isn't available like on a 50cc scooter.

 

[Mike St]

I'm going to test a robin 35cc/pocketbike cvt against a 49cc Huasheng/q-matic
against a FD/honda gx50. Have all three bikes ready to test. I'm looking
for torque and acceleration and a good day.

 

[2speedboi]

Too bad a simple light weight CVT isn't available like on a 50cc scooter.

I'm going to test a robin 35cc/pocketbike cvt against a 49cc Huasheng/q-matic
against a FD/honda gx50. Have all three bikes ready to test. I'm looking
for torque and acceleration and a good day.

Did you have pictures of the competition? Id like to see this robin trans