Friction roller help

[ohio1228]

So i have my 31cc Ryobi 700r weed eater engine mounted to my bike. Now my problem is attaching a friction roller to it. I have not yet created a friction roller.

-The shaft on the engine has a square in the middle of it, and there are no threads in it.

Has anyone else ever seen this before? Is this square shaft typical on all weed eaters? Any recommendations on what to do to mount a friction roller to it? And what would make a good roller?

 

[a_dam]

This sounds familiar; the part about "a square in the middle of the shaft". Is that the actual motor shaft or the output of a clutch? Is the shaft square on the outside, or is there a square hole in the shaft? Can you post some pics?

There's always a way to rig something up. I would have tried to figure out the details of the final drive configuration before mounting the motor to the frame.

Many people recommend knurled bmx pegs for friction rollers, but there are a lot of different ways to go. It depends on what kind of bike/tires. Does it need to grip when wet? Is this just for playing on around town, or do you need a dependable, long-range setup?

 

[deacon]

Most likely you have either a clutch bell a big round device on the end of the drive shaft or if no clutch a sleeve over the actual drive shaft. The clutch type is a muther to mount to. I always took mine off and worked directly to the drive shaft. I think some tried to use the clutch, I'm not sure how much success they had with that.

The clutch is held on by a phillips screw at the inside and end of that square opening. It will be hard to turn but it will move eventually. I have had to cut the tube off to get to that one. If you have a clutch you most likely will have a 3/8 fine thread on the drive shaft. I think it is a backward thread if I remember right. I haven't built one of these in a while.

If it is a sleeve it will run from the flywheel and is about two inches long. That one has a nut kind of thing at the bottom of the sleeve. You just turn it off but it might turn backwards so keep that in mind.. If you have the sleeve i would turn it off and then slip the whole sleeve inside something to use as a drive wheel and have it welded it on.

But remember this balance is very very important. Out of balance and it will vibrate the motor apart. I did several of them that way. Also you will need to lock the engine down to turn off either the clutch or the sleeve. To do that take the spark plug out and stuff a clean rope or rag down the hole. Be sure to leave enough out to pull on when you are finished taking the clutch or sleeve off.