Vertical crankshaft lawn mower engine on a bicycle?



i just wanna do this simply
no clutch, not much money invested, on a mountain bike.
im not even a hobbyist but my uncle kinda knows how to "mount" stuff..
if i cant find a horizontal shaft engine, what do i do?

and if i can find one, whats the best/easiest way of mounting it?
i mean, let it spin the bicycle chain? the wheel (directly)? or with a wheeltop friction drive?
i thought of it just being like mounting it on the side of the rear wheel axis, and let it turn the wheel directly..

and what should i do if i can only find a vertical shaft engine?

Thanks alot,

I don't know how easy it would be to adapt the vertical engine so that its output at some point becomes where the horizontal engine starts off at but if you look at an older DR field mower they take a horizontal engine and (through a single twisted belt) they make the horizontal engine act like a vertical engine to drive the could probably rig up some sort of twisted belt drive to power the bike BUT the vertical engine is most likely wider then the same HP horizontal engine so that may pose some problems with mounting the engine itself and being able to pedal.....May be easier to barter with somebody and trade the old vertical engine for a horizontal engine.

Hope this helps.

i honstly have no clue lol but i found a great 6.5 hp side shaft on sale this week at harbor frieght, 130 buckeroos, if your uncle is a good mounter, that would be a kick butt engine to put on, the same price as a happy time. might try a weed eater with an all position carb, if you search davids farm on u tube he has a cool setup, and he did everything him self, im more of a bolt-on fan myself :)
I was looking at riding lawnmower racing sites and had a pretty amazing brainstorm.
If I can get a riding lawnmower transmission which is essentially all you need for it comes with an axle and hook up a lawnmower engine,then get some wheels and make it a pusher trailer it would be so fly.
I mean,you can electric start the puppy,maybe cable down the gear shifter (GEARS!!) and with it being two wheels you can even cover the whole thing to look like just a trailer...until you push the start button.
I hear some of those lawnmowers can go like 60 miles an hour!

I got these pics from here:


  • Trans008.jpg
    60.7 KB · Views: 5,195
  • Trans001.jpg
    60.4 KB · Views: 4,151
I often dream of a shaft drive bike. Your vertical shaft could have a u-joint welded on and connected to a drive shaft to the rear axle. A mini BMW. Just dreaming.
Shaft Driven Bike

I read somewhere though, when force of pedaling has to change direction, some power is lost.
So if ya pedal downwards, and the shaft has to spin 90 degree via gears, then another 90 degrees to spin the wheel, some power is lost in comparison to direct chain pedling.
But hey, what are motors for ?
If this type of concept can be added to a bike, then the engine's chain drive may be where the front pedal gear was, but on the left side ?
Fantastic concept...dunno though how good it would be at standing up to abuse.
The next time i'm around that area i'll drop in and maybe(maybe) they'll let me go for a ride...if not i'll take more detailed pics and ask questions.
So I got this riding lawn mower at craiglist for free and it's a bonified way of running a vertical shaft engine for your bike if you make it into a trailer pusher. The only thing right now though is that that gearbox is so geared down that if I changed the pullys to get it back to speed it's gonna be spinning a whole lot inside there. Well I could always pack it with some gear lube.
Here's the original thread:
I probably won't use that engine. 6 horse is overkill. Pretty hard pulling anyway. I'm gonna scrounge around for a regular lawnmower engine hopefully with a key start.
It would be a lot easier if I found a horizontal drive for I could do away with that tranny altogether but I want this to work.
Stay tuned.