somebody build me

deacon · #1 (**permalink**) 05-05-2008, 11:29 AM

Okay I need a friction drive for the china engine. I am getting so sick of the chain drive I don't know what to do. So here is what I need.

Take an alum or steel channel.
Use brass busings to run a shaft through with a sprocket on the motor side to drive a shaft with a friction drive roller on it. You might half to do a gear thing to make it change directions but it shouldn't be all that hard to do. I can rig the tie downs no problem. It would be just a bolt down on the wishbone behind the seat, then a couple of down rods to the rear axle. Nothing to it for someone with a good shop.

That kind of rig would eliminate broken spokes, chains jumping off in he middle of traffic, and give another option for the china bike kit. I know I'm the only one with a desire to run friction drive these days, but I swear I think it is more dependable.

The reason I like the china girl engine for the power source is the the clutch. A motors that sit on the tire running continually will wear spots in the tire for sure, but the clutch would make it like my electric where I just shut it down before it spins.

So build it and they will come, at least I will if the price is right.

Come on Norman you and a lot of other guys can do this no sweat

VENICE BOY · #2 (**permalink**) 05-05-2008, 12:03 PM

You might not have to make it change directions! These engines should run in both!
(I don't know what might happen with any oilling holes inside?)
But it should run backward! (I know my RC car engines do.)
Actually, you might have a problem with the ignition?
Has anyone ever tried to run one of these engines backward???

deacon · #3 (**permalink**) 05-05-2008, 12:49 PM

I never even considered that it might run backwards. Now wouldn't that be neat for a friction drive kit. just an alum channel with a hole drilled straight though Probably have to weld the drive wheel on after it was inside the channel. or maybe not I don't have enough experience with these things to know.

how about a long bolt inserted through the pedal side, through a bushing, then through the friction drive wheel, then through the channel then double bolt a sprocket on loose enough to move inside the bushing.

Or just drill and put a pin through the drive wheel to hold it. That is if the motor would run backwards. I might be able to buy all the parts off the shelf.

VENICE BOY · #4 (**permalink**) 05-05-2008, 01:19 PM

I might just do a little experiment today & see if it will run backward!
I'll let you know what happens...

jezusjonz · #5 (**permalink**) 05-05-2008, 01:58 PM

Quote:

Originally Posted by VENICE BOY

I might just do a little experiment today & see if it will run backward!
I'll let you know what happens...

Hey did you ever do this?? just curious.

deacon · #6 (**permalink**) 05-05-2008, 01:59 PM

That would be great, because I think I have figured out an easy way to make a drive wheel assembly from the rear axle of a coaster bike. I need to check on a sprocket.

It looks like you can take two big butted steel shelf L brackets and cut and weld them to a large channel configuration. They have threads on each end so in theory it would but just a matter of some nuts in the right places.

The sprocket would have to go inside the frame because of the wishbone of the bike. Any guess as to what size sprocket would be good to use. Since it is friction my guess it that it wouldn't matter too much.

Skyliner70cc · #7 (**permalink**) 05-05-2008, 06:23 PM

Deacon,
I'm sorry to hear you are having problems. I have yet to experience any of those problems on well over 2 dozen builds under my belt. I typically put 50-100 miles on a bike before I market it for sale.

Each of your issues is easily solved with a little more attention during the build. Good luck in pursuing a friction drive.

toytime · #8 (**permalink**) 05-05-2008, 06:24 PM

Hey deacan, It's very hard to put into words but an air filled small rubber tire works great as a "friction drive" I have done it and it NEVER spins or wears bald spots into your tire. I used a 8 inch tire with sprocket attached. Have you ever noticed that most rides use this method at your local fairgrounds! If you face the engine towards the rear, you don't have to worry about jackshafts and running backwards. It's not as foolish as it may sound.

deacon · #9 (**permalink**) 05-05-2008, 07:06 PM

thanks skyliner...

Toy wouldn't reversing the engine cause the chain to come out facing the front of the bike.

I am using a plastic wheel from a caster now on my electric bike.

I had planned to have the sprocket welded right to the drive wheel either way I go. Whether the wheel revolves on the shaft or the shaft revolves in the bracket, I think I'm going to go with the sprocket welded to the drive wheel.

toytime · #10 (**permalink**) 05-05-2008, 07:20 PM

Yes it would but I'm talking about a rear rack setup. If you were looking at the bike from the front , you would see a seat, the "drive wheel" and then the engine.
The set up I built was with an electric motor so I was able to turn the motor upside down, solving the bike wanting to go in reverse, if you know what I mean. It would be interesting to see a china girl run upside down, I think the carb would have to be mounted in reverse and everything would be fine. As far as welding your wheel, have a look at the cheap electric scooters. All the parts you need are there, including a small drive wheel with a sprocket attached. It's very hard to put into words but I will help if you ask.