Bicycle powered by. . .a chainsaw?

[theunchosen]

Alright, this is odd.

I happened to be repairing one of the chainsaws( I live in the woods so cutting up dead trees and burning them as firewood is cheap heating(Its a complicated wood burning system not just a straight up fireplace because that sucks air in from outside, I know)).

I noticed that the drive on the chainsaw happens to mate almost exactly with the chain on my road bike. This got me thinking, since I only really need one of the chainsaws(No one ever helps out lol) and since the weather is pretty nice. . .

How do we feel about powering a bicycle solely by a chainsaw?

The roadbike is very light and I'm pretty confident I can switch out the assembly with not alot of effort if I just want the bike back. Its a 4-5ish horsepower chainsaw(its a little older and I suspect the compression ring isn't all there, but it still works fine to chop stuff up.

Fuel consumption at full tilt is substantially less than a gallon per hour(as much as I can estimate it uses about a half gallon for an hour WOT). Obviously on a total weight of less than 200 lbs(me and the bike) I'm not going to need WOT for my morning commute. I'll need WOT uphills, and thats about it.

This is a goof off project that I am only likely to spend about an hour. As of now all I would have to do is move the throttle control to the handle and mount it.

[Bicycle Bob]

2 stroke mopeds usually have much smaller engines, but still produce far more pollution than cars.

[NiHaoMike]

I have actually seen a bicycle powered by a chainsaw engine. It was converted to run on propane as well. However, it only went about as fast as a normal bicycle due to poor gearing.

[Frank Lee]

I noticed that the drive on the chainsaw happens to mate almost exactly with the chain on my road bike.

No way.

[theunchosen]

Originally Posted by Frank Lee

No way.

This road bike is pretty old and I've never seen or heard of the brand anywhere else lol.

I slipped the chain over the teeth (bike chain) and it fit. . .but I can see it being a problem under load(slipping) So I'll have to do a little of something.

I'm thinking drop the plate from the chain saw and use the gears from the bike. . .?

[DonR]

I think without using a jackshaft your RPMs will be way to low to power from the chain. I would look at using a small friction wheel on the clutch up against the rear tire. I think the gearing would work out better.

Emissions
I had heard that Husqvarna (sp) was using a spark arrester screen coated with catylitic converter metals to greatly reduce 2 stroke engine emissions.

Don

[theunchosen]

Yeah I had thought about this a little. The saw has trouble at low speeds unless you gun it to high rpm and then it can slowly coast down to lower than you can hold and cut. . .but I'm not at all certain if thats more a function of the blade or the engine.

Both are much less effective at low RPM I know for sure, but I can't help but wonder if the saw would be able to pull it out from a stop. Acceleration won't really be an issue(unless it won't) so I guess I'll just have to test it out first?

[Frank Lee]

I have a Stihl that I wanted to put on a bike once upon a time.

Since then I've decided that a four-stroker would be much better- preferably Honda 50cc

[theunchosen]

I would prefer a four stroke as well. . .but I don't think I can find a four stroke for about 30 bucks. Fleabay has working 50+cc chainsaws going for about 30 bucks plus shipping.

If they actually work or not. . .I dunno. . .

[blueflame]

Tire drive is extremely simple though does have some problems.

Otherwise, first up your front and rear sprockets will need to be determined. HP you give at 4-5hp.... so its a big saw?

Most scooters have around 3 HP which allows 65km/hr on a 80kg machine with tons of drive gear drag.... so a 5hp bicycle will be a rocket. Your cycle chain would be too small and snap unless you grannyied it.

Try a 29cc off a weedwacker. Cheap as chips, even new and super light. Buy with a warranty. I have a Honda 4 stroke weed wacker- perfect!.

A MTB disk brake cycle rear disk can be removed from rear hub, modified to install a very large/but light belt pulley with a tiny belt pulley(alloy) on the wacker motor shaft. Or you could cable tie a big pulley to the spokes???Attach to the rim???

Ideally mounting the drive train in such a way that the bike could be used just pedaling with motor disengaged. Another ideal feature would be being able to bump start, rather than get off and pull start.

Pulse and glide should be designed in..... especially considering its a cycle as pushing and pedaling can move the vehicle as well.

Hypermiled with even an inefficient 2 stroke wacker motor, FE with PulseGlide could be as high as 500mpg....maybe 2000mpg depending on how much you want to pedal.

One way to engage and disengage the motor could be like a handbrake type lever mounted on the cycle top tube operating a cable, actuating a cam that moves the motor away from the rear axle thus tightening the rear belt and engaging the motor.

Early mopeds drove the tyre with a nolathane/rubber/urethane bush on the engine shaft. These bushes typically lasted around 1000km and required special tyres that wore too I believe. However, tire drive has potential, especially if a tyre was made with a ring gear incorporated into the sidewall. Personally I like the idea of disk brake hubs on MTB's to secure large pulleys with the handbrake type engagement. The early Velocycles's were difficult to pedal and heavy.

This area is ripe for redesign and innovation, as the plethora of electric hub motor bicycles would suggest. Rocketing down the road at 45mph on a cycle with ordinary frame strength, braking and handling may require life insurance.

What ever happened to Tidalfoce?

IO Tidal Force Electric Bikes by Wavecrest

Rim drive....axle less wheels.....aerofront cycles.....sails.....wings....liftoff....big leg muscles