Chainsaw Friction drive begins maybe

The problem may be that the late model saws are in a plastic case. They unbolt and make a nifty R/C airplane engine, but the only way to mount it to a bike is probably use the bar mounting studs somehow. The case holds the ignition module on some models and is also the cooling ducting. Check it out before you buy it and be sure you can mount it. Older saws were metal cased and are easier to mount maybe. I have used the old Homelite Xl-12 saws on a few karts in the past with good results. Would go on a bike pretty well but are harder to find now.
 
I have used the plastic cased one once before but I cant remember how I set the frame. Seems like it was bolted on using the bottom bolts of the say case. I used a very very large hose band I think to hold it steady. I raised the whole saw to get it off the clutch to start and idle. I have no idea whether I can use the clutch or not. Some of them are mounted backwards with the sprocket inside those are useless for what I need. Some have the sprocket outside and those I can maybe weld to the sprocket. I will have to wait and see the guy had a 42cc craftsman and he said i can bring the gas and try it before I buy it. So thats what I will do
 
The first image is how the chainsaw looks with the blade and chain removed. It is a view of the clutch. this one has an outer sprocket.
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I removed the chain keeper, then welded a nut onto the sprocket. It is a 5/8 nut I think. I will let you know when I get to a hardware store to buy the bolt that fits it. I might be able to do that today if the snow holds off a few more minutes. The image below is the nut welded on to the sprocket.




http://img156.imageshack.us/img156/6964/csclutchnut.jpg
 
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I started the chainsaw with the drive wheel. I gunned it one time and the wheel flew across the room. The corners of the sprocket broke off. So that didn't work. It's back to the drawing board.

Im thinking now direct drive and gravity clutch.
 
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OKay what I did for a drive was to remove the clutch and use the nut that holds it to the drive shaft. I am going to weld a 5/8 nut to the clutch nut. The a second 5/8 nut to that one then a two inch bolt with nuts all the way up it. It should give me a drive just a little over two inches and about 3/4" in diameter. I might need to weld a sleeve over it someday but for right now I'm going to give it a try. I should get some good pull going up the hills around here. That is more important to me than top end I think. We shall see what we shall see.

We are having snow and freezing rain right now so the welding will have to wait for dryer weather.
I found one minor inconvenience that might prove to be a real drag. The bike will have to be laid on its side to add gasoline since the was designed to be turned on its side to fill it. Not a problem unless it is hanging on a bicycle.
 
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In my tradition of reporting success and failures as I go along. I have to report that my welding sucked. The welded nuts on the old clutch nut lasted about two seconds before it separated and flue against that wall. At least it missed the windows. I would hate in this weather to have to replace glass. Although there is no heat in the shop so it wouldn't make a lot of difference I suppose.

Okay plan a was to weld a nut onto the clutch bell. A person with better welding skills could have done that I'm sure. Then plan b was to weld nuts to the clutch nut, that was this mornings failure. So now it is on to plan c the old stand bye. This one I have done several times with weed eaters.

I will go to home depot and pick up a 1.5 inch pipe nipple and a 1.5 inch end cap. I will drill a 3/8" hole in the end cap slide it down over the drive shaft, then use a fender washer and the clutch nut to hold it in place. Since the motor runs clockwise, I will have to super glue the threads on the pipe nipple so that it wont unwind on me.

That friction drive kit is looking better all the time lol...
 
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Why not weld the pipe to the clutch drum? That way you dont have to rely on the nut holding it on. Might be a ***** to install the keeper ring though. Heres a pic of a friction drive I bought years ago, works well. Has a clutch handle like a motorcycle you pull in to declutch, could be locked for pedaling. Installed in about 15min. It is a Canadian TML industrial engine of 41ccs as I remember. Its drive roller is threaded directly to the crankshaft. Yopu could do similar with your pipe cap if you can find a LH tap of the proper size, just have to weld the pipe to the cap. Guess I oughta stick this thing in the for sale section.
 
Forgot the pic!
 

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Oh happy day. I found an old axle peg from my earlier friction drive days. It is one that is about an inch in diameter inside with a perfectly centered 3/8" hold drilled in it. So I managed to get the clutch nut cut down enough to go inside it. It could be a little longer but I think it will do. If I need to I'll find one a little longer and replace it.

So now it is mount the thing on a bike and rig a lift for it. And a throttle and kill switch of course.

http://img833.imageshack.us/i/csdrive.jpg/
 
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Im thinking about using the chainsaw itself as one rail of the motor frame. The craftsman has this insanely large rear trigger area. I can clamp over it. I have to do more thinking but I think it will work.
 
Im thinking about using the chainsaw itself as one rail of the motor frame. The craftsman has this insanely large rear trigger area. I can clamp over it. I have to do more thinking but I think it will work.
 
I am trying to keep the chainsaw bike looking as much like a chainsaw as possible, I mean whats the use having a chainsaw bike if it doesn't look like a chainsaw. So can somebody who uses chainsaws tell me,What will the kick back (chain brake) do since there is no chain. Will it effect the motor in anyway.

It is my hope to rig a throttle and kill switch using the original controls. A cable through the top of the handle should work the existing trigger throttle. and something to flip the kill switch on the saw.
 
The chain brake should present no problem as long as it isnt inadvertantly hit while in operation. It only locks the clutch drum so the engine has to be above idle to be affected.
 
Thanks the clutch drum is gone so it shouldn't be a problem. The handle is too long to use. I'm going to have to trim it off. I hope I can save the chainsaw look. I'm going to try to save some of it at least the trigger part if possible.
 
well while trying to cut the case so that I could use most of it, I managed to compromise the gas tank. A nice way of saying the tank leaks now. So after this cup of coffee and warming my toes, I will remove the case to see what I need to do to make it work now. This is sure fun a lot of fun. If it were nice weather and I could be riding, I might be upset but there is snow on the ground and it's cold. So I don't mind the hassle so much.. I just run in and out to work on the motor. I did get the test bike back to the point where it has a kick stand and is ready to mount the motor. That is when I get it fixed.
 
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If you just have a crack or cut in the tank, you can usually repair it with a solder gun. It is of low enough temp to be ok around the fuel residue. I just repaired my fuel gauge float in my 72 Bug this way.
 
well im an idiot lol. Actually I have a brain tumor that is growing and everyday I get a little more stupid and a little more clumsy so the chainsaw bike is history. I managed to break the carb as I tried to get to the fuel lines to move them. Don't ask it was difficult. between my general bad luck with gas bikes and my wife complaining about the small of gasoline, it's time for me to go back to my ebike and stop trying to be a genius. Actually I feel fine. I just have a higher since of stupid these days. So take care everybody i might come back later and try something with ebikes.
 
Sorry to hear your project came to an end. I've been lurking around follwing your thread. I only like the DIY projects, and love to see people's innovative way of getting around problems. I've built a few chainsaw friction bikes but lately I've been just rebuilding chainsaws for resale and cutting wood.
What kind of carb was on there, I've got a few spares lying around here. Did the fuel line nipple break off the carb? You might be able to fix that. Then plastic weld that tank and you'll be back on track.
Pics of the carb would help.
kev1n
 
Just a final note: The craftsman 42 was the same saw that I broke the drive shaft off on my last chainsaw build before I went Ebike, a couple of years ago. So last night I shut it all down and I noticed something. The drive shaft was bent on the saw I had been working with. No matter if I had gotten it set up or not, I would have started with a bent drive shaft. I didn't drop the saw, the only thing I had been doing was trying to mount it. So it appears that the drive roller bent the saw just from holding the saws weight while I tried to adjust it to the wheel. I don't think I would hook it up as a direct drive if I were you guys. That drive shaft just isn't strong enough on that saw.//
 
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