Motor On Mountain Bike

[ineed2fly]

Looking to toss an engine on an old 24" mountain bike, (small snowblower engine) and because of the frame style, I can't mount it inside the frame, it needs to go over the tire. At least I can't burn my legs though! So first off I have no idea what type of engine it is, or how much power it has. All I know is I ripped it off a snowblower for my chopper like 3 years ago and never got around to doing it. If I had to take a wild guess, 3HP. So I want to weld on a mounting like strut structure thingy off the yellow portion of the rear so I can keep the suspension, and then run a chain down from a centrifugal clutch down to a cog on the wheel. I believe the crankshaft is 5/8, but I'm not 100% sure. :rolleyes3: not to mention it isn't keyed the whole way, it only has a notch for a woodruff key And then there is the issue of the clutch takes #35 chain, and the cog on the wheel is for bike chain..... So I think I need to take off the cassette, and figure out how to mount a 60 tooth #35 sprocket. And then the derailer+pedals come off. So yeah any help would be super awesome!

Picture #1:
The number on the flywheel guard says: 1603 9345

Picture #2:
The carb side of the engine, I believe a diaphragm carb?

Picture #3:
Bussiness end of the engine, shows mounting bracket well.

Picture #4:
Bike I want to mount it on, yes that is my neighbors sexy sexy FJ-40 across the street, and his Porche....lucky is 17!

Picture #5:
Where I want to mount the engine, my dad is a photographer, hence the "say cheese" plate

Picture #6
The cassette

 

[ElectricalBen]

ok i did this with a weedeater engine but does your engine spin the right way to use it on the sproket if the bike

 

[ineed2fly]

Here is what I am thinking of for the mounting cage thing. They are different colors for clarification, the red on this side of the bike, the blue to the far side.

Oh and be carefull if you google that number under pictures, w/ safe search off (have it set that way for more results) you get :arf: BOOBIES!!!!




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[ineed2fly]

Yes the engine turns the right way, but #35 chain won't work on those!

 

[ElectricalBen]

i think 40 chain fits but its so wide it wouldent shift right 35 is to small right.. and you would do fine with a belt drive and the right pulley ratio... because with a whimpy weedeater engine i had a 1:18 ratio and i topped out at 45 when i resize some of my pics ill post them

 

[ironman]

if that chain swings around it wont be a sweat bee stinging you thats for sure.

 

[ineed2fly]

I'll put a guard on it for sure. I'm not going to deal with having it shift, just a single gear, so what should I use? A 60 tooth given that it's a 24" tire? The speed calculator with a 24" tire, 60 tooth sprocket, 3600 rpm, and 12 tooth clutch, will hit.......dear god.....51mph! EEK!

 

[ElectricalBen]

yeah that probly work but if you used the engine on the other side you could use a smaller gear and pedal start but get a higher speed

 

[ironman]

yea that sounds good man thats going to be a scary first ride around the block.

 

[ineed2fly]

Why? Actually in thinking about it I hit 45 on my bike like everyday on my way to work.....YAY! I will see if I can keep one gear in the back so I can use it as an assist motor. Is there any way like using a jackshaft, to have it go from the clutch, to jackshaft, to bike chain, to wheel? Then I could just leave that cassette on there! And have an assist motor, and then just hook it up to the biggest gear. And then the other thing, how do those direct drive ones work? Like where it sits right on the tire? Cuz I need NOTHING to do that, I have all the stuff for that around my house.

 

[ineed2fly]

I'm going with the friction drive doohicky, so yeah we'll see what happens, I should have it drivable by this afternoon, but we'll see what happens.

 

[ineed2fly]

It runs!!! HAZA!!! Riding it to work today

 

[T-BONE]

Video?

 

[ineed2fly]

I don't have any way of compressing the video, so it's always a massive file, but I can see if I can find something. DUDE it does like 30mph! I'm thinking I should put a lawnmower wheel on the crankshaft, not a skateboard wheel. :arf:

 

[SloS13]

try this http://www.microsoft.com/windows/windowsmedia/forpros/encoder/default.mspx

 

[ElectricalBen]

friction will wear down your tire kinda fast but or when its wet but it is a easy method and proven

 

[ineed2fly]

Yeah, ****ed thing will hit about 30 down hill, YAY! And then I just hooked up the hand throttle, (Don't need to reach back anymore) and it's like 1 so I don't want to wake the neighbors. I put a muffler from a B+S (sister of the one on my kart) so it's a bit quiter, but it's not really a proper 2 stroke muffler. It's the most ghetto thing ever though! The bike is a bike I found in the trash, the engine is mounted on tubing from a bike seat, and a wheelbarrow, the engine is from a snowblower, the muffler is from the B+S, the gas tank is bungied on, there is a piece of ply hotglued to the tank to keep the exaust pipe from melting through.......ahem (again) ahem.... Thank god for gas tank sealant. And then the throttle cable has zip-tie in it so I could shorten it so it would be tight.

I have a mac.....so I can't really use that software. But I can get some pics up tomorrow.

But the drive wheel is pretty soft rubber, not like cross-hatched metal like the commerial ones, and it's a mountain bike tire, so I think it will stay in service for a while.

 

[ironman]

post up new pictures.........you might have just saved the world from the gas crises.....i hear a million dollar contract coming your way pictures and video is a must get someone to film for you . next you need to figure how many miles a gallon

 

[ineed2fly]

Fill it with a gallon, and just hit a parking lot till it dies? But like these things tend to get 100-200mpg...that would take forever!

 

[gocartkid]

I DEMAND pics and a vid!