I decided to put an engine on my bike for quick trips to the grocery store, blockbuster, etc. This setup should get between 150-200mpg when its done.

Here's where I'm at on the 2nd evening of my build. My Fuji mountain bike has a thin aluminum frame, so I had to fabricate some custom mounts.

Right now, I have it set up with rubber motor mounts isolating the engine from the frame. I might need to go back to a solid mount to drop the motor a bit, as the spark plug is IMO too close to the top tube of the bike.

Here are some photos:

This build brought to you by Killian's Irish Red.... mmmm




CLoseups of front and rear mounts.



A closeup of both mounts: I'm going to have to heat and bend the exhaust a little bit to clear the frame.


One extreme to the other.. Mercedes Unimog, 11mpg. Fuji Motor Assisted Bike, 150-200mpg.




A good view of the mounts. The rear is actually twisted to the side to clear the chain:





Here is how the drive sprocket is attached to the rear wheel:



Tommorrow night is the fuel tank and control mounting.

Wheree's the front driveshaft

that engine is very narrow- can you get a chambered exhaust for that motor?( 2-stroke, right)?

i have something similar.

i used a ross 10 speed coz it has a free wheel sprocket on the crank.i doubled the smaller inside sprocket on the bike crank and use the clutch and chain from the mini bike.

i mounted the engine similar to yours but i use leather straps.

the larger sprocket on the crank runs the normal bike chain to the back

i will run about 60 mph but is way to fast to be safe ..
i keep 100 psi in the tires
and put a disc brake set up on the front.

and used a 3/12 hp briggs/stratton minibike engine .
it is pull start and i use the gear selector as a throttle..

i am sorry not to have pictures.

the ross bike was the key .. it is the only bike i know that has a free wheel bearing on the crank.
this allows the pedals to be used kinda normally.
i mean you can keep you feet at a normal position while the engine turns the sprocket.

i do not really know how many miles to the gallon .
also i have a smaller in length spark plug and a half inch water pipe aprx 2 1/2 feet in length as a muffler..going to the back of the bike.it is covered with a 2 inch sheet metal tube to protect from the heat.

i ended up heat ing the clutch springs, which made them a little weaker, coz it would take off too fast.
i also had to switch the crank to the other side
and flipped the rear wheel to match.
i bypassed the govener once but reconnected it
it simply was too much power and speed..

30 is comfortable and easy ..
40 is pushing the technology of the frame and brakes
50 and 60 is asking for trouble.

John, you should really seek professional help.

Once you do, I'm coming over and riding that sucker because that looks fun!

Once you get this working, you should do kits...you can do my Trek next

They sell kits.. this is what this engine is.

If you want one, they run around $250 for the whole shebang, plus $50 or so for misc stuff.

http://www.kingsmotorbikes.com/

There are lots of other suppliers too. Just look up "bicycle engine" in google. They are all basically the same thing. Chinese 2 stroke, but can vary from 48cc up to 67cc (more torque). The one I got is a 67cc.

You can also score them dirt cheap on ebay. I've seen them sell for as little as $100.

Quality is a real crapshoot. Most of the hardware in my kit is garbage, so I am using bolts and studs from Ace hardware to replace all the questionable stuff. I also had to make engine mounts as seen above. The original mounts were spindly things that I wouldnt have used even if they did fit my bike. These engines usually have bushings in the connecting rod/crank, but can be replaced with bearings to make them last longer. Most people get ~5k miles out of them after a careful break-in. I'll be running 20:1 gas/oil mix.

power wheelies?

with some porting and polishing, mabye. These little 2 stroke engines make around 2-3hp. The gearing is set up that you have to pedal a bit to get started. They wont easily start off from a stop.

I hve read about guys being able to pull a wheelie on these after working the engine over a little.

Kits available? LOL That looks ANGRY.
John, for a project with so much potential gheyness, you never cease to amaze me. I am taking notes. That thing is cool. I could see me riding that.

You may have to register it as a moped.

Nah, here in AZ, they passed a law saying motorized bikes are legal as long as you stay under 20mph and the engine is supposed to be a 49cc or less. Requires no registration, insurance, or license to operate.

Of course, mine is a 67cc, but the engine casing is identical to the smaller engines and there are no markings, so noone is going to know.

Definitely ANGRY!

I actually have a second engine kit coming in the mail. Looking to do an oldschool looking cruiser. WWII style motorbike using a new Felt MP!

I'll convert the frame into a gas tank. Everything would be olive drab including the engine, carb, and exhaust.


Either the MP or one of these Swiss Condors from the late 1930s from cold war remarketing:

Another option would be the Felt 1903:

$500.00 motor bike is not bad. However it it only last a few hundred miles......

Yeah, we'll see how long it lasts. I could always toss another motor on there off something else.

Most folks get at least a few thousand miles on them before they have to replace parts. There is nothing to the engine, so pulling the head to swap out wrist pin bearings is a 30 minute job.

I'd love to do this... but I will probably need two motors,

And steel belted heavy duty tires?


Don't worry, Flipper asked me if I was in my second trimester yet.