Completed Frame Mount CVT

[Shrapnel]

I'm new to this site but wanted to show my own use of the pocket bike cvt on my mountian bike. Here is the setup:

Zenoah 51cc engine (peak power 3.2HP @ 9000rpm)
Pocket Bike CVT with 11 tooth pinion sprocket for BF05T 8mm chain
72 tooth BF05T 8mm chain sprocket mounted on a freewheel

Back when Staton-Inc still carried the CVT, they said it had 1.9:1 to 1:1.1 variability in the belt/pulley system, multiplied by the 3.714:1 gearbox. I've measured the diameters that the belt rides on the pulley and took apart the gearbox and counted the teeth and got about the same numbers.

It rides great and will pull me up any hill. Takes off good from a stop and accelerates quickly. I don't know the top speed, but it's about as fast as I want to go.

[capturedbyrobots]

Those 51cc geos are pretty awesome.
I like the 8mm chain too.
Good job, I just wish you still had pedals...

[eastwoodo4]

looks like the pedals woulda cleared.

[Shrapnel]

Yeah, the pedals would have cleared, but the freewheel I'm using only allows for one sprocket to be attached to it. They do make some left-hand threaded freewheels that I could have used with Staton's special hub to make it left hand drive and keep the pedal side free, but I just went with what I had.

It's more of an "ultralight motorcycle" than a motorized bicycle now. The whole thing weighs less than 50 lbs. If I had any fabrication skills, it'd be a whole lot nicer.

[eastwoodo4]

looking at it a little closer i see why u cant pedal it.u know u can attach those cvt`s to the motor in any position u want right?i have one just like it.then u could put it behind the seat

[Shrapnel]

The first time I built it I mounted the engine on a luggage rack. It really made the bike back heavy. This time I tried to keep the weight as balanced as possible, front to rear and side to side.

If I do it again, I'll try to mount the engine lower to keep the center of gravity as low as possible. Of course, that means I won't have any shot of putting pedals back on it (but I don't really like pedals anyway, that's why I put the engine on it).

[loquin]

Unfortunately, in most states, a motorized bike without pedals is a motorcycle, no questions asked, and needs to be licensed, insured, etc.

[Shrapnel]

That's one of the perks to living in Indiana. If I had a 50cc engine or smaller (instead of my 51cc), I'd be street legal without any registration. Any scooters in Indiana 50cc and under don't need registration, and you don't need a license to ride them (even nice ones like the Yamaha Zuma).

As mentioned above, mine doesn't meet the street legality requirements due to engine displacement, but I don't commute on it. It's just a fun project that spends most of it's time in my garage.

[heathyoung]

Nice job - you could use a flip-flop hub and run the pedals as LHD, CVT as RHD. Most of those 8mm sprockets have a freewheel that is a standard ISO jobbie, and the lower teeth freewheels (ie. 14/15 for pedal side) are 30X1's - which suits the other side of the hub.

[Shrapnel]

I took some pointers from the folks over on GopedNation.com and rebuilt the CVT with new bearings and modified the housing as shown in the pics for better cooling.

I just used some relatively cheap bearings from McMaster-Carr, but it seemed to make a good difference. The bearings I used were all rated for 1500lb axial load, and they were very smooth rolling. I also ditched the grease in the gearbox in favor of 10W30 motor oil. There is a lot less drag in the gearbox now, but the oil leaks slightly where the driven shaft goes through the inside of the CVT box.

I took the bike out today and clocked it at 35 mph, and it still has enough torque to do burnouts. The only weak point I'm currently having is the freewheel that the rear sprocket mounts to. I've smoked two of them now from abuse. I just need to stop abusing it or find something stronger.