Does anyone have any input on the use of chainsaw engines on these bikes? Looks like I posted in the wrong forum. My bad.
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Anyone using chainsaw engines
- Thread starter mtndistiller
- Start date
I built a bike with a chainsaw last year and have another chainsaw on the way now. I broke the drive shaft on the first one I built. I hope I have better luck with this one. But I build friction drive bikes.
Deacon, What type of gearing set up did you use? Also what do you mean by your drive shaft broke? Thank you
There is a lot to know about friction drive. First of all there are kits now that let you hook a centrifugal clutch to the kit. There there is the direct drive which is what I built. To do that you attach a wheel or pipe to the drive shave of an engine. Usually they say some between one and two inches is best. that wheel or roller rides on top of the rear wheel of the bicycle and turns the bike wheel which propels the bike forward. Sometimes backward if you hook it up wrong.
In the case of the last chainsaw I built that broke the drive shaft of the motor. I hooked a heavy wheel up to the drive shaft. It was a drive roller sort of like what they use on a goped. I had welded it to the threaded slug of the clutch. I devised a lifting lever to raise the motor to start it and get it off the wheel when I got to a stop sign. Now that part worked just fine.
What I think broke the shaft was the weight of the roller plus the fact that I was running it on a knobby tire, plus the fact that I had it attached to a full suspension bike. All that led to shocks on the drive shaft of the motor. So somewhere outside of my house the drive wheel left the motor.
When i get the used motor I bought on ebay, if it runs, I plan to remove the clutch again. This time I plan to weld the slug to a 1/2" nut then attach a plastic skateboard wheel to the drive shaft of the chainsaw engine. I also plan to use it on a bmx type tire and a hard tail bike. I will have to devise a lift system aka gravity clutch for the bike. Of course I also have to rig a throttle and build the mount but thats all pretty straight forward. I am hoping that this one lasts a little longer.
I have been running a friction drive ebike for the last year and it works fine but it uses a chain from the motor to the wheel of a scooter rear wheel mounted in a frame over the rear bike wheel. See my avatar. Building friction drive is different from chain drive but it isn't all that much easier. Well the kit would be very easy to install. I have no idea how long lasting the engine is but I do know that a chainsaw last a long time. That is my thinking on going back to try it again.
In the case of the last chainsaw I built that broke the drive shaft of the motor. I hooked a heavy wheel up to the drive shaft. It was a drive roller sort of like what they use on a goped. I had welded it to the threaded slug of the clutch. I devised a lifting lever to raise the motor to start it and get it off the wheel when I got to a stop sign. Now that part worked just fine.
What I think broke the shaft was the weight of the roller plus the fact that I was running it on a knobby tire, plus the fact that I had it attached to a full suspension bike. All that led to shocks on the drive shaft of the motor. So somewhere outside of my house the drive wheel left the motor.
When i get the used motor I bought on ebay, if it runs, I plan to remove the clutch again. This time I plan to weld the slug to a 1/2" nut then attach a plastic skateboard wheel to the drive shaft of the chainsaw engine. I also plan to use it on a bmx type tire and a hard tail bike. I will have to devise a lift system aka gravity clutch for the bike. Of course I also have to rig a throttle and build the mount but thats all pretty straight forward. I am hoping that this one lasts a little longer.
I have been running a friction drive ebike for the last year and it works fine but it uses a chain from the motor to the wheel of a scooter rear wheel mounted in a frame over the rear bike wheel. See my avatar. Building friction drive is different from chain drive but it isn't all that much easier. Well the kit would be very easy to install. I have no idea how long lasting the engine is but I do know that a chainsaw last a long time. That is my thinking on going back to try it again.
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took the muffler off so you could see the clutch bell, with the 3-inch pipe welded to it. it was an older aluminum-case homelite saw,lots of cutting and grinding was done to clean it up, then it was flat-blacked.there are 2 separate hinged arms from a sit-up machine holding the motor there, one has 2 screws in the bottom of the motor, the other has 2 in the top. the 4 holes were originally there to keep the engine tight inside it's aluminum shroud/case. it had a spring for tension but it got caught on something and stretched out...i dont ride it in the cold so i havn't put another on.
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I remember some time ago a guy in France had built a bike with a chainsaw mounted above the rear wheel. All he used, if I remember correctly, was the bell clutch left on the saw and had that resting on his rear wheel. I thought it was pretty cool and wish I had an extra chainsaw to use for a bike.
I heard that one as well. It would definitely be easier than what I am thinking. I might take a look at that as well. I wonder if a cambell's soup can is the same size as that clutch bell.
so that bell is exactly three inches.?
so that bell is exactly three inches.?
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Thank you everyone for replying. I first got interested in these MBs when I saw one and thought it would be fun to build one and play with. Then I read a lot of material on them and came to the conclusion that the "China girl" kits are typical Chinese junk. So I thought since I have running chainsaw engines and bicycles I would just try and marry them together. That's what landed me here. I didn't even see this DIY forum till I posted in the wrong forum and it got moved. I have good skills in welding and fabricating so my initial thought was to mount the engine in the frame. Then use a centrifical (sp) clutch, jack shaft and some gearing to get the job done. But after seeing the simplicity of a friction drive it seem like a viable option.
oh it is and if you can weld and keep the drive more or less in balance it will probably be a long lasting engine for you. Avoid mountain bike tires and suspension rear ends is my only advice. As for friction drive, it is by far my favorite drive. I can change a tire a lot easier than changing parts on a chain driven bike. I buy bikes at the thrift show so I usually have plenty of good tires and tubes laying about.
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I found the link for the one from that guy from France that did a chainsaw build.
http://motorbicycling.com/f14/hello-france-6325.html
Deacon, you asked the size of the bell? Depends I guess. My two saws are husky's and their about that at least. My old homelite (a big heavy mutha!) is about 3 1/2" though.
http://motorbicycling.com/f14/hello-france-6325.html
Deacon, you asked the size of the bell? Depends I guess. My two saws are husky's and their about that at least. My old homelite (a big heavy mutha!) is about 3 1/2" though.
I really really like the one with the belt drive. Now the question is could you use a 5mm scooter belt on the sprocket. If you could do that then you would use one of the belt drive rear wheels as a drive wheel for the bike. I think the sprocket is 3/8" which is about ten mm I think. Or maybe I could use a wider belt on the scooter wheel without it coming off all the time.
