how to advice needed - friction drive

brucemg51 · #1 (**permalink**) 08-23-2008, 12:48 PM

I am so thoroughly disgusted

with those chinese chains and sprockets that I can't stand the thought of another build with them. Here's my idea. A 42cc chain saw engine. I've gotten lots of mounting ideas. My question right now is how to attach a drive roller onto the drive shaft of the engine. Centrifugal clutch and pull starter looks real appealing. That drum sanding drill attachment I thought would make a great friction roller, but how to attach it?

deacon · #2 (**permalink**) 08-23-2008, 01:24 PM

I cant help you I took my clutch off my chainsaw. I attached my drive directly to the drive shaft of the engine. I use a gravity clutch which is no more than raising and lowering the engine.

I agree about the china bike by the way it's why I got interested in the diy friction drives.

How about welding a sleeve over the drum sander's shaft then welding the sleeve to the clutch drive gear.

brucemg51 · #3 (**permalink**) 08-23-2008, 02:28 PM

Quote:

Originally Posted by deacon

I cant help you I took my clutch off my chainsaw. I attached my drive directly to the drive shaft of the engine. I use a gravity clutch which is no more than raising and lowering the engine.

I agree about the china bike by the way it's why I got interested in the diy friction drives.

How about welding a sleeve over the drum sander's shaft then welding the sleeve to the clutch drive gear.

So you're saying an alternative would be to remove the centrifugal clutch and attach the roller directly to the engine's drive shaft? Then, by using a lever and cable you could lower the engine onto the tire after you got pedaling along. I think I've seen that done somewhere. Question: wouldn't that leave just the weight of engine pressing down to make contact with the tire and would that be enough to prevent slippage? What I've seen is using a quick disconnect and slotted supports to raise or lower the engine. That way you can force the engine down onto the tire with some pressure, then lock it in place.

deacon · #4 (**permalink**) 08-23-2008, 03:33 PM

For that you use a door spring. You need some extra tension for sure. The spring also stabilizes the engine on bumps ect. You need the spring on something like it even with a centrifugal clutch.

To be honest I don't know who strong a chainsaw clutch is. With a chainsaw you would still have your rope start since it is on the other end of the drive shaft. A chainsaw is pretty heavy but I rode mine today.

I lever it down then tie if off to start it. When I am seated I pull the brake lever clutch and release the tie off loop. then when I am moving I slowly lower the drive onto the tire.

comfortableshoes · #5 (**permalink**) 08-23-2008, 03:51 PM

I used to use a slotted bracket for mine, but THAT leaves a lot of pressure on the drive roller and however it attaches. When I did that I sheared off an attachment. It sucked to pedal home. Now I use a heavy door spring and a item I can't for the life of me remember the name of to perfect the tension. When I hit a bump, the spring allows the engine to move with the tire- no more broken shafts.

Even if I went back to using a clutch on either of my engines I would use the spring tensioner- it just seems more forgiving for the engine.

deacon · #6 (**permalink**) 08-23-2008, 04:14 PM

Turnbuckle???

comfortableshoes · #7 (**permalink**) 08-23-2008, 04:19 PM

deacon- YES that's it! complete brain fart on my part.

deacon · #8 (**permalink**) 08-23-2008, 04:30 PM

I have one but my springs are so long I dont have room for it lol...

brucemg51 · #9 (**permalink**) 08-23-2008, 06:06 PM

Quote:

Originally Posted by comfortableshoes

I used to use a slotted bracket for mine, but THAT leaves a lot of pressure on the drive roller and however it attaches. When I did that I sheared off an attachment. It sucked to pedal home. Now I use a heavy door spring and a item I can't for the life of me remember the name of to perfect the tension. When I hit a bump, the spring allows the engine to move with the tire- no more broken shafts.

Even if I went back to using a clutch on either of my engines I would use the spring tensioner- it just seems more forgiving for the engine.

I'm guessing you mean that if you lock the engine down rigidly with slotted mounts, it can't move with the bumps, which it could with springs and turnbuckles.

comfortableshoes · #10 (**permalink**) 08-23-2008, 06:27 PM

Quote:

Originally Posted by brucemg51

I'm guessing you mean that if you lock the engine down rigidly with slotted mounts, it can't move with the bumps, which it could with springs and turnbuckles.

exactly. springs and turnbuckles act like shocks.