Back in the game maybe

deacon

deacon

minor bike philosopher
I ordered a chainsaw from ebay. If I can make it run, I'm going to figure a way to use it on a friction bike. Im thinking weld a couple of nuts to the chainsaw sprocket and then bolt a skateboard wheel onto it as a drive wheel. then I need to make a motor mount. This is in advance of buying a friction drive kit.

I just want to see if I can still think clearly enough to build one. In the end I'm pretty sure I'm going t buy a friction kit.

has anybody ever done this if so help me out here.
 
It will prolly have the small 54mm centrifugal clutch which I'm not sure if that is adaptable to normal friction drive mounts. Just something too consider, that's all.
 
The skateboard wheel should provide ample gear reduction. Do you have any ideas for taming the sound of the chainsaw exhaust?
I was considering a weedeater engine build but I hate the exhaust sound.
I await your chainsaw build with baited breath.
 
Last time i built with weed eaters that actually worked, I drilled holes to make them even louder. and breath better so I thought. I don't know about exhaust this time. I have been looking at things on the net today about the motor I have coming. I think the sprocket for the chainsaw chain is 3/4 inch in diameter. If so I think I am going to go the double up nut route.

Get one to fit over the sprocket then center and weld it on. After that match up a second nut to the first and weld it to that one. At that point if I do a half decent job I should be able to run a bolt through a skateboard wheel and into the second nut. With my welding I can only hope that it stays together and that I don't have the shaft too far out of balance. If that works I will have a drive wheel and a centrifugal clutch on the end of the drive shaft. If it doesn't I'll go with the old gravity clutch. Just lift the whole thing off the tire. That is if I can get it started at all.

You know I built one like this before with a chainsaw but the bike I put it on was a full suspension and I had the drive directly on the drive shaft. Also knobby tires so that after a few days it broke the drive shaft. That was a real drag. I did like the dual suspension but I liked that motor better. That one was 42cc this one is 33 cc I think. One of the things that is neat about friction drive is that it makes no difference at all the size of the bike wheel, that all go the same speed that of the drive wheel.
 
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I use the skate board wheel blanks no bearings. Put a big washer on each end then tighten the bolt down hard. Leave enough sticking out to screw into the nut I have welded to the motor. I have used it a couple of times. Like I said one time I broke a drive shaft so there is no guarantees doing it that way. I doubt that I can get the thing balanced it might just shake apart. We will see what happens and I'll let you guys know.
 
I have been thinking about the drive system for the chainsaw bike. I decided that when the chainsaw comes, if I can get the motor running, I'm going down to the hardware store to bye a steel pipe nipple just a little smaller than the sprocket part of the clutch system.

If you have a chain saw you know that the teeth are funky, they go right up to the clutch housing with no bevel at all. They are very thick as well. I'm going to try to cut notches in the end of the pipe nipple, so the it will fit down over the sprocket and it should be large enough to clear the nut. Then I can hit the notches with a bit of a weld and if even one of them holds it will be enough,. It will probably take an inch pipe or maybe a little larger to make it over the sprocket. That will be the drive roller. I will have to resurface it for sure. I am thinking cut an old tire and try to gorilla glue it to the pipe nipple. It will hold sandpaper to one of those things, so maybe it will hold the tire tread. If not I'll just hit it with some welding rod slag.

I have also been thinking I want to keep the motor looking like a chainsaw. I think I am going to try to drill a hole in the handle where the trigger is and mount a cable through it to squeeze the trigger rather than go directly to the carb with the cable/
 
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I just watched a video of a guy changing the clutch and sprocket on a poulan chain saw. It looks as thought I won't be able to make an easy adapter after all. Oh well I can work something out I'm sure. Last time I just removed the clutch completely and bought a left handed 3/8 inch nut. or maybe I used the clutch parts. I hope it will come back to me.
 
yeah you could use a 2 or 3 inch pipe and fit right over the chainsaw-sprocket on the clutch bell....i welded a 3 inch piece of galvanized tube on the clutch bell itself.i had to weld it in small sections at a time to not warp the bell. i can throw up a picture of it for everyone's amusement.
 
Now that's an idea I am back to the weld a nut to the clutch lug and then bolt a skateboard wheel there. It means a gravity clutch and those are tricky. But according to all the info I can find this motor won't weight much more than a weed eater. Maybe I can work it out.



My welding is so crappy that it would just be a huge mess. But all options are open now.
 
Now that I have decided that I most likely can't use the centrifugal clutch, I have begun to drag long forgotten things out of my mind. Oh where oh where is my partner in crime. How can I butcher bikes and engines without comfortable shoes. Oh well, we made a clutch, back in the day, by constructing scissor hinges to hold the motor straight. Then used a spring to keep the tension on once the motor was lowered to the wheel. To lift and lower the motor we used levers and cables with a control bolted to the bike frame. Push it forward and the motor rose about an inch or so. Pull it back and the tension was gone so the spring pulled the motor down. And that's what I'm going to rig to disengage the motor when I am at a stop sign.

Again that is assuming I can make the motor run. By the way last time I worked on a chainsaw motor, I used a carb from a weed whacker because the one on the chainsaw was bad. I might have to do that again, I hope not. But it does seem that most of those carbs are interchanable except for the amount of gas they throw. If I remember right I could adjust for that at least some.
 
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Since it's Christmas day and my motor is still in the mail somewhere, I just looked on ebay and found lots of non running chainsaws for around fifty bucks. My guess is most have carb problems since most of them are stored for long periods. The diaphragms probably need to be replaced. I am going to try to clean mine with carb cleaner and maybe restore the rubber with brake fluid before I rebuild the carb. that is simply because. if that will rejuvenate the diaphragm, it will make bringing the motors back to life a lot easier. I don't plan to buy too many more, but I might need to replace them on a fairly regular basis since a cheap chainsaw isn't designed to run everyday year for long periods year round.

Anyway I'm looking forward to building with the chainsaw again. It should be a learning experience and I do love to learn.
 
I have been doing some more research before the motor arrives and it looks as though this model and all the other 33cc poulan motors has the sprocket on the outside of the clutch. I might be able to weld a nut onto that sprocket then run the skate board wheel onto it. My worry is that the heat will screw up the needle bearings and then I have no idea what will happen.

If I can get away with it, then I can keep the clutch in place. If not i might still have to deal with the gravity clutch.
 
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There are a few things I have done before so I know they work and a few I would like to try to see if they work. First of all I want to try to weld a 1/2" nut to the sprocket of the chainsaw clutch bell. If that works I would have a clutch on the chainsaw for my friction drive the easiest possible way. If not I have devised this rube Goldberg style gravity clutch imagine this if you can

A square frame of angle steel, hinged to the bar that bolts the bike's wishbone. Each side of the motor mount held in place at the rear with scissor hinges made of two pieces of chain link fence wire stretcher bars about five inches long and bolted together.

One hinge has a long metal rod going to the front of the bike where it is hooked to a lever that pulls it back and forth. Moving the lever it pulls the rod from the hinge, which in turn raises and lower the engine by opening and closing the hinge. On the opposite side of the wheel the same kind of hinge has a spring that puts tensing on the motor when it is on the tire. The hinges on the side not only raise and lower the engine, they keep the engine straight one the bike. I have used this hinge system often but never with the rod going to the front of the bike or the spring to keep the tension on the motor drive.

It's really rube Goldberg but I think it will work.
 
I think my motor is snowbound. It was sent parcel post from vermont last week. I figured it would come this will maybe but I think now it might be two weeks. Oh well it's too cold to mess with it anyway.
 
It looks as thought my chainsaw is still being held up by the blizzard. Oh well even thought the weather is better, I am still not quite ready to begin working on it anyway. Maybe by the time I'm over the Christmas bug the motor will be here. I might do a step by step report on the build as i did with the ebike build. There seems to be a lot of interest in the chainsaws all of a sudden.

I'm trying to salvage my old digital camera. If I can't I might have to buy another cheap one. I have all this great film equipment and negative scanners I hate to invest in a fancy digital camera at my age. Anyway I have found that I can buy factory reconditioned chainsaws pretty cheap at sears. Not sure if I really want to do that or not at this point. I would like to experiment with this cheap used one to see if I can build a usable system before i put a Cnote into a chainsaw. If I can get the bugs worked out, I think I will get something like this http://www.sears.com/shc/s/p_10153_12605_SPM2083846503P?prdNo=20&blockNo=20&blockType=G20 to do a serious build.

I can probably get the mount made and the other things like throttle and kill switch done for slightly under the price of an ebay kit. I think the motor might be a little better on the chainsaw than the motor in those kits. Thats my thinking If i'm wrong please tell me.
 
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