Friction Drives

Well, the best way we used involved a drill press and the dremel. Just when down it in a straight line all the way around it. I will post pics of the upgradded ribs we are gonna try on my spare Peg. I am also gonna try the JB Weld and see if I can work out a magic combination of items to use.
 
I used jbweld and salt but it wore off in a couple of hours. I had jb quick set so that might have been the problem.

I used jb to attach an old tire and that seemed to work except where there was no tread it wore down to the casing pretty quickly. I have a different configuration now I'm going to try that tomorrow.
 
Deacon, recently one of my neighbors had me working on his green weed eater blower. It was a smaller cc engine that ran on one setting.....wide open.

I hadn't worked on or used one without the trigger to throttle it before, but after I fixed it and used it a day or so.....it made as much sense as any other types of blowers. With it being a blower there was no load on it to stop it so you had to press down on the choke lever to where it said stop to cut the engine. With a bike the braking down to a stop would accomplish the same ends.

Your reasoning makes sense to me based on the experience I had with that blower. I'd keep my eyes on the rubber brake pads thought as they would serve a dual role in stopping the bike and the engine along with it.

But those are some thoughts I'd offer. It'll be interesting to hear your report
of how this works out for you.
 
I remember my 25cc when I started it I just put the throttle on full power. After that I ran it wide open at least 95% of the time. I used the coaster brake to stop it and when I did the engine died when it got down to about four miles per hour.

I am going to use the brake lever for a front brake (what a novel idea) to help with stopping. I hope the engine coming has a kill wire so that I can rig an emergency kill switch.

I figure it will take just a little getting used to. For instance I can remember making turns with the 25cc required pedaling hard after the turn to get the speed back up. It was a matter of taking the load off the engine. I'm not sure how it will work, but if it doesn't then I will put a rudimentary throttle on it.

I would love to get hold of bunch of old shifters from somewhere as they are ideal for home brew throttles. Buying them on ebay is just too expensive for parts. I think I will put a note in the swap shop,.
 
Deacon, the only problem I see is slowing down enough to kill the engine. Even with the small engine I have, mine was hard to stop with it idling high. My mixture screw and idle screw was messed up and it ran like it was half throttle. Even with the brake pressed it seemed to drag me a good distance before I stopped. I almost crashed into my truck in the driveway.
 
Good point...

I might need to go to a two possition throttle then. run and stop.. Idle and wide open. I'm going to try no throttle but have a kill switch first to see how it does.

But you have a point stopping distance might be a problem.

I tried my second rendition of the tire jb'ed to the drive wheel. Evidently I did something wrong. This one fell off but the case of the first one under it is still there. I bought a new nipple and jb welded a bit of tire onto it in the cross pattern that works best.

I rode the bike a couple of miles with just the casing on the drive wheel and even that does better than nothing on it. matter of fact it is still on there after about two miles. I think the new wheel will work, just have to let it cure a couple of days. Since I bought a couple of new drives, I might do one with jb and sand just to see.
 
Of course it ain't tinkering till you mess something up.

My Fuel to air ratio is all messed up. It can run like the devil for about 3/4 mile at full throttle and 3/4 choke. but the moment I touch that choke beyond that it wants to bog down and lose power. And after the engine gets to 3/4 a mile it gets warmed up to where It wants more..and bog downs and dies.
 
My latest built ran great yesterday but I got the tension wrong today and it ran like crap. I had too much tension on it. I am going to try again tomorrow. It does much better when it skips some. When it pulls all the time it can't get up to full throttle. Tomorrow I'm going to try some new drive wheels and less tension.

So yeah it's build then tweek then adjust and tinker lol. Actually it's fun.
 
My latest built ran great yesterday but I got the tension wrong today and it ran like crap. I had too much tension on it. I am going to try again tomorrow. It does much better when it skips some. When it pulls all the time it can't get up to full throttle. Tomorrow I'm going to try some new drive wheels and less tension.

So yeah it's build then tweek then adjust and tinker lol. Actually it's all fun.
 
I thought about the tension on my bike and I want to adjust it but I will have make a new bracket or extend the holes on the existing one. The problem with extending the holes is if the adjustment is not a good one and I want to go back to the way it was I will have a hard time keeping the motor down. Any thoughts? Mine is mounted on a single bracket.
 
I have my 25cc built on a hinge. Can you use your mount and put it on a hinge for swing. then add and L bracket to go over the tire and an adjustable rod down to the opposite side axle to use for tension. Just slot the bottom hole. I know it's a pain to make but it might be useful to be able to change the tension adjustment.
 
I have an old GoPed I think I will snake the power off the thing and install it on a bike. I need to increase the size of the drive roller, it is less than 1". I modified the ped a few years ago and made it so it would idle at a stop, and installed balloon tires. I hinged the after section and installed a pedal to press after a push off, It works OK, but it will make it easy to install on a bike, I will take the whole aft section, hinge and all just two bolts on the sides. Have fun, Dave
 
Most everyone I talk to thinks the goped would be a perfect friction drive conversion. Most thing of using the goped rear drive system complete. Bolt er on and go. Good luck.
 
Thanks, I think this one will be easy as I cut off the whole rear section and made it move so I could have it run stopped. I never used it, it is too wobbly, and prone to let you off at any time. I have a good time watching what you are building. I have the most fun building the stuff I have, almost as much as riding it. I am still trying to figure out a way to install a rotary mower engine over the rear wheel. It would remain in the mower orientation, this would keep it low profile, and the power would be more than you would ever need so it would be smooth quiet running. I was thinking of a two roller outfit running on the brake shoulders of the rim, one roller would be just a dummy and the other on the end of the crank, to give you the pinching affect, what do you think?. And there are millions of them out there. Have fun, Dave

PS: The engines are self contained and it is easy to install a compression release so you could just ride off and let it go like a Whizzer.
 
It never occurred to me to run the drive against the rim. We could do that with weed eaters as well. I have one that just arrived with a very very long shaft.

It would have to be very secure so it wouldn't shift from the torque but that's very doable. It would have to be a drag start I think. Since right off hand I can't think of a clutch mechanize. Unless you could use something like a side pull brake yoke.

On the weedeater, I think a start stop drag would do. I have the 31cc so that it will drag start now. I didn't think it every would.

you know what? you might not need a clutch on it. It might just slip on the metal rim when the wheel is locked down. With a soft skateboard wheel you might not have a problem at all.

It would take some experimenting but I bet it would work just fine.
 
Deacon - If you look at the rim you will notice that there is a slight taper from top to bottom. On the lawnmower engine it is so stiff that it would not be hard to have a wheel on ether side. For a small engine you could use a piece of channel with a wheel mounted inside and the other on the end of the crank, that way it would not try and move over, also I was thinking that you would lower the engine away from the taper and raise it up to engage, as it was raised it would get tighter on the rim. The nice thing is it would not rub the rubber off the tire. One thing I noticed on the GoPed engine is that it is using a very small shaft to drive it. The engine is a 21cc and it gets the thing along pretty well, I think on the small engines you are using I don't think you can use a shaft larger than 1/2" I have a 49cc and I have a 7/8" on it and it can use a larger one but the small engines need a small shaft. I put a pic of the engine, you can see the shaft, and the way I cut the mount to make it move up and down to give a out of gear place, you step on a pedal to force the engine down on the tire. You can see the piece of sanding belt I contact cemented to the shaft also, you have to keep the engine tight on the wheel or you know what happens. Have fun, Dave
 

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The older ryobi 31cc had a 3/8 diameter shaft but the newer one I am working with now has a 5/16 shaft. All of the 25cc have had the 5/16 shaft. I haven't gone to the shop yet this morning but I'm going to take a look at this idea. Especially with the 25cc and it's lower compression allowing it to drag start and stop so easily.

Sorry I just realized that you were talking about the diameter of the drive wheel. I was confused I thought you meant the drive shaft on the engine.

My drive wheels are over an inch. So you are saying I need smaller drive wheels and more contact with the tire itself.

I can easily go back and check that out this morning. the job of interchangeable drive wheels. I can fit a 3/4" od drive wheel and even add a little to it if I need to do that. I will give it a try with a one inch drive this morning and see what the effect is. I think I tried it and decided that it needed more speed for the hills. But I haven't tried it since I opened up the muffler for more back flow.
 
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I'm working on the friction drive with the GoPed engine, I think it is going to be an easy install. I am using the mods that I did to the rear section of the engine bracket, and I am going to try and make the engine lift with a handle. Ill post a pic. I have another Idea for a rim drive also, Ill give that a go later. Have fun, Dave

PS: I am going to try and use the holders for the brakes, using a piece of angle Iron to hook my pivot points to. I should not interfere with the brakes.
 

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