Weed Eater Friction Drive Bicycle

I have been reading the forum for some roller ideas, and I have decided to go with the one Deacon used on one of his builds. He used a pipe nipple and end cap, and attached that to his output shaft. I am getting the goods today, and will let you know what happens
 
This is what I picked up today. I got a piece of galvanised pipe with an inch outer diameter, as well as an endcap for the pipe. I had the place put some thread on the end so that I can screw the cap on.

What I am going to do is drill a hole (hopefully dead centre) in the cap, attach it to the motor shaft, and then screw the pipe on, using loctite as well. I will cut some grooves in the pipe with my angle grinder to give it some roughness for my tyre. Hopefully this will help a bit with my poor torque.
 

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If the cap is going to seat against the flywheel its gotta be flat and true. If you are going to leave it seated at the bottom of the threads it got to be drilled real TRUE or it will whip like crazy. The only way(I know of) to get a true running roller is center drill it in a lathe. If you are into the WE thing long term it might be worth getting a local machine shop to make you a roller from 1" steel bar stock. It will run true. They can counter bore it and true the face so it will tighten down against the flywheel properly. I make my own prop hubs for aluminum bar stock in this manner and they run very true. I cant imagine this would break the bank, and it would be transferable to different engines for a long time. I believe deacon got fairly short engine life with the pipe. might wanna PM him and ask. Not trying to discourage experimentation, thats what its all about. just offering some advice.
 
cannonball2 said:
If the cap is going to seat against the flywheel its gotta be flat and true. If you are going to leave it seated at the bottom of the threads it got to be drilled real TRUE or it will whip like crazy. The only way(I know of) to get a true running roller is center drill it in a lathe. If you are into the WE thing long term it might be worth getting a local machine shop to make you a roller from 1" steel bar stock. It will run true. They can counter bore it and true the face so it will tighten down against the flywheel properly. I make my own prop hubs for aluminum bar stock in this manner and they run very true. I cant imagine this would break the bank, and it would be transferable to different engines for a long time. I believe deacon got fairly short engine life with the pipe. might wanna PM him and ask. Not trying to discourage experimentation, thats what its all about. just offering some advice.
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Thanks for the advice cannonball. As you say, I am experimenting, and all the advice that I can get is welcome. I was going to ask a machine shop to drill the hole for me, as well as flatten out the raised top of the cap. I was also thinking of getting a machine shop to do a whole roller for me, but I haven't gotten any quotes on prices yet. I don't want to mess the engine up, so I am going to take this slow.
 
It occurred to me after posting this that you must have a long shaft engine. This will work a bit better then. Still the pipe end against the flywheel needs to be very true. Back to the machine shop, all they would have to do is center drill and true a piece of bar stock, no threading. Just slip it over the shaft and tighten her up with the nut. Would pay dividends in engine longevity.
 
cannonball2 said:
It occurred to me after posting this that you must have a long shaft engine. This will work a bit better then. Still the pipe end against the flywheel needs to be very true. Back to the machine shop, all they would have to do is center drill and true a piece of bar stock, no threading. Just slip it over the shaft and tighten her up with the nut. Would pay dividends in engine longevity.
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Yes, I do have a long shaft engine. There is a pic of it somewhere in the thread. I think your idea regarding a piece of drilled bar stock is a good idea. I might have a look and see how much that will cost me.

I will keep you posted
 
Would a Goped drive spindle work? I don't know how long they are, but they come in different diameters and sell for under $10 on Ebay. According to a Youtube video, the are bolted on. Why not drill out the center. It would be best to chuck in a lathe as cannonball2 stated.

http://tinyurl.com/6vd9vtl

Good Luck,

Chris
AKA: BigBlue
 
I decided to go to a machine shop, and ask them to make a roller for me. I drew up some plans that I gave to them. I asked them that I need a 110mm long piece of 1 inch diameter round bar, with a 9.5mm diameter hole, drilled 55mm into the bar. I then need a further hole of 22mm which is threaded with an 8X1 thread.

The first drawing below shows the bar that I need made, and the second drawing shows the shaft that it is going to slide over and screw onto.

It is going to cost me about $11 to get it all done.
 

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Yesterday I got my roller that I had made at a machinist. It looks really nice. I still have to test it out, but hopefully it works a lot better than the 1.5 inch peg that I had
 

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I have the same motor but its about 20 years old and doesn't have a primer,that came off a leaf blower. The thing has to be choked out to start. I've done the same thing with the bike peg. Do you mind if I use your schematic for the roller to have one of my own made? Mine is a 32cc and sounds like a dirt bike. My motor spins counter clock-wise... I'm not sure but are you sure your motor is running the right way? I've started mine with the motor on the wrong side and it lugged and was lacking power.

cvlt1
 
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You can can use my diagram with pleasure. My engine runs fine, it just had no torque with the large roller. I havent tested the new one yet because i am at the beach for the weekend. I will let you all know next week how it rides now.
 
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I tried out the roller on my bike yesterday, and it works very well!! It still struggles on hills, but on flats and downhills it is fine. I just have to tension the roller a bit more, and maybe roughen it up a bit more.

I now have to manufacture a clutch for myself. I was holding off from doing that before I knew if this would work.
 
Seems I remember you are using the Homelite/Ryobi(had a yellow boom?) If so they dont make great power as compared to the original Homelites. Heep an eye out for an older blower of USA manfacture, most are 30cc. Some were 25 so check it out carefully. It should be a direct bolt on repacement with more power. I have converted many Homeys for R/C use including 2 of the later types. I was disapointed in them and dont use that type any more. Its not a bad engine, but has been redesigned for emissions Im sure and lost power in the process.
 
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