chainsaw bike starting

can you post pics?

id say your roller would be your starter...just pedal up to speed and engage the motor...should bump start it...

take pictures of what you've got going and im sure some of the diy experts would be more willing to wage theories tips and tricks...

I think, you should still be able to utilize the pullstart...but I wont know until I see pics of your setup

Most chainsaws have a clutch so your pull start should still work just fine.
If you do NOT have a built in clutch, engaging the roller will start it like wickedest1 said.
I've seen several BMX friction builds that simply pedaled off till it started with no roller in/out mechanism at all.

The clutch should be centrifugal on the chainsaws drive sprocket. The pull start will work, but depending on the clutch setup you probably won't be able to bump start it.

I tried a chainsaw bike once. It worked for a little bit, but for some reason I couldn't get it to not shift. Of course, it was probably the fact that I rack mounted it. Every time I accelerated on it, the rack would shift to one side. If you were able to take that design and improve on it, it would probably be pretty sweet.

http://motorbicycling.com/showthread.php?t=45545

Has anyone ever successfully used the clutch with a friction drive weedwacker or chainsaw? I mean, I know it will work, but for how long? Once the cent clutch engages, is it strong enough to drive a man on a bike without slipping and burning up?

On my builds, the pull start is removed once I know the motor is all sorted out. Bump start from then on. Then I use a motor lift system to engage/disengage friction drive. I must admit, though, that the clutch on my Echo weedwacker looks pretty stout. About 3 inch diameter with beefy-looking shoes. Still don't plan to use clutch in a FD build.

Are you referring to having the clutch drum ride directly on the tire?

a_dam said:

Has anyone ever successfully used the clutch with a friction drive weedwacker or chainsaw? I mean, I know it will work, but for how long? Once the cent clutch engages, is it strong enough to drive a man on a bike without slipping and burning up?

On my builds, the pull start is removed once I know the motor is all sorted out. Bump start from then on. Then I use a motor lift system to engage/disengage friction drive. I must admit, though, that the clutch on my Echo weedwacker looks pretty stout. About 3 inch diameter with beefy-looking shoes. Still don't plan to use clutch in a FD build.

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I have a KS bike machine motor that. Was made back in the 60's it has a clutch, has about 3" . Sure is nice to pull up to a stop without having to do anything,just hit the gas and go ...........Curt

curtisfox said:

I have a KS bike machine motor that. Was made back in the 60's it has a clutch, has about 3" . Sure is nice to pull up to a stop without having to do anything,just hit the gas and go ...........Curt

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any chance for a pic? maybe some close ups of how the motor is mounted and the drive system?

The clutch would have incredible stress on the bushing if you tried to friction drive directly from the clutch bell. It would need some form of bearing support to operate properly. The side loads from friction driving would destroy the bushing between clutch bell and inner shoe mechanism in short order.
Adding a shaft and roller with bearings that was clutch driven seems possible. Simply find a way to couple the sprocket to a shaft, like a flexible two rwo row chain coupler would be adaptable to the sprocket on a clutch bell. Think half clutch, half this:

Wickedest1 said:

any chance for a pic? maybe some close ups of how the motor is mounted and the drive system?

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I am on the road traveling and all my ifo is at my home computer. But it is the same as a pocket bike engine with a clutch, infact if i can't get my motor to run right this summer i will use the pocket bike engine. It is set up the same way as a weed eater with bearing in the houseing and a bearing on the outer end. try and google a ' K&S Bike Machine Motor and see what you find. Dax,and Staton have a simular setup but the K&S has a better lift lever all you do is reach back and move the lever with a shift knob on it and it lifts the motor for pedaling.
Instead a steel frame it has a cast aluminum frame that the roller fits between. they were sold back in the 50's and 60's and were addvertized in popular machanic mag. Mitchabechy engine( fogive the spelling ) But is realy the best friction drive i have ever seen,it is a shame that no one reproduces it again. Would be super kool with a Honda 4 stroke on it and in aam sure it would bolt on there.........Cuer