[TxCyclist]

Where are you buying your motors? I have a friend one with he mounted but it's very old and uses a basic setup with a spoke with teeth that grip the wheel. Pretty inefficient.

 

[47Steve]

Tecumseh has a durable 49cc 2-cycle engine -- used on little rototillers and other small equipment and small portable pumps. They've been around a long, long time.

Tanaka has several very good small 2-cycle engines -- a quality Japanese company that has great 2-cycle designs.

Search the internet . . . there are lots of bike motor kits out there. Avoid cheap chinese engines -- you have no way to know the quality of the components or of the metal used to cast the engines.

 

[coondogg69]

Would you recommend going to a garage sale and buying someone's old weed eater and getting the motor off of it?

 

[d57tbird]

RAW Chinese motor kit

I bought a RAW Chinese 2 cycle 80cc motor kit (66cc actual) off eBay for $120 with free shipping. comes with everything needed for the conversion of my 1953 Huffy Dial a Ride bike. I also installed heavy duty Worksman cycle rims with Atom drum brakes, and a double brake lever to actuate both brakes with right hand, leaving the left hand open for the clutch. I had to machine the sprocket and fab a larger mounting ring for the drum brake hub. Have not completed it yet or run the motor...will post again concerning performance of motor and any issues with longevity if any. Plenty of Youtube videos with kits like mine out there, so some must be running fine. I like the old school look of my project. Motor fit well with some modifications such as home made spacer block and longer metric studs from local hardware store.

 

[Neuromancer]

It has to get up to at least 70 for the flux capacitor to work!

 

[s2pyd]

I would rather get a really small motor that is 4 stroke, is this possible? 2 strokes seem to smoke and stink alot and if you have that on your bike in an inconvenient place your probably going to get smogged out

 

[JustJohnny]

You would have to get a little sprocket thing and weld it to the end of the motor shaft....... how much is a welding machine I can do that with?

 

[47Steve]

I would rather get a really small motor that is 4 stroke, is this possible? 2 strokes seem to smoke and stink alot and if you have that on your bike in an inconvenient place your probably going to get smogged out

Yes, Honda makes a very small 4-stroke and it's a good engine. The thing I like about 2-strokes is their simplicity -- basically three moving parts (piston, connecting rod, crankshaft) vs. about 30 moving parts for a 4-stroke. There may be other good Japanese small 4-stroke engines by companies like Mitsubishi, Kawasaki or Subaru.

My 2-cycle moped has a catalytic converter in the exhaust pipe and emits no smoke and not much 2-cycle stink, either. I'm happy with it.

Tanaka has a catalytic converter on their engines, too, I think.

If I were going to build a motorized bike, I'd want to consider the sound quality and noise level of whatever engine I chose. Some of the engine manufacturers advertise that they are pretty quiet.

 

[47Steve]

You would have to get a little sprocket thing and weld it to the end of the motor shaft....... how much is a welding machine I can do that with?

Don't try to weld the sprocket onto the shaft -- sprockets wear out and must be replaced, and the welding heat to the shaft may melt the shaft seal.

 

[mothra]

Whats a good way to attach it then? Would a belt system with a torque converter work?

 

[47Steve]

Whats a good way to attach it then? Would a belt system with a torque converter work?

There are several methods in use.

The most simple approach is to put a roller of about 1-1/2 to 2" diameter on the output shaft of the motor and mount it so that presses on your tire. A lever gizmo pulls the roller off the tire when you want to stop or ride by pedalling. You can also incorporate a centrifugal clutch. By selecting a roller of the right diameter, you can optimize the "gear ratio" of your drive -- smaller roller = slower speed but more hill climbing ability. The old Solex mopeds had this setup. Also several add-on bike kits use this method, either on the front wheel or the back wheel. Disadvantage: tires wear rapidly. A design that is too simple will put too much force on the motor's crankshaft bearing and cause premature failure.

Add a centrifugal clutch and a small pulley on the engine (may be available as a single unit) and drive a large pully on the wheel via v-belt or cog belt.

Add a centrifugal clutch and reduction gear with sprocket output, and drive a sprocket on the wheel. A few folks have figured out how to mount such a setup to drive the rear derailleur, for a transmission effect, and terrifying top speed.

Some European mopeds use a "variator", which is a belt-driven CVT transmission, like a snowmobile has. They work well. Other European mopeds use a 2-speed automatic gear transmission, which also works well. Some are single speed, which makes them slower.

 

[buckrogers007]

...no smoke from my 2-stroke..why? I by the 100% synthetic oil mix and it says on bottle, No smoke My motor have no smoke and no stink

 

[buckrogers007]

I like 2-stroke for sound and traffic hears me and turns their head which is rare on a bike. To me, it is not loud.

The 4-strokes that just came out are belt driven or can use the 415 HD chain.
The kits are usually 4-500 bucks for 4-stroke. Quitter...have to pull start though
kit come with wider crank to accommodate for engine width on the 4-stroke if putting in middle of frame.
Parts are a little higher than 2-stroke parts.
I like that I can peddel and when want motor just release the clutch and pristo on the 2-strokes.
I like bicycle-engine dot com 4-stroke kits and price.

 

[buckrogers007]

..here is a pic of my 50cc 2-stroke motor on a Schwinn cruiser.
IMO, I can do a top notch build with best tires and parts for $600 for myself..that is using a Schwinn lakeshore cruiser from walmart (steel frame is still better they say than aluminum) and it comes with cantilever brake mounts on front and back..most cruiser bikes don't seem to have these and just a kids coaster brake Not good in the motorbike world going faster and may need to move crank up or down and cannot.
Plus fenders and rear rack for $170...damn that is good
Ps. the pic below is not a lakeshore Schwinn, this one is an older Schwinn model stripped and repainted. But the newer Scwhinn have 2 fender or rack bolt holes is the noticeable difference.

Peace

 

[Ykick]

Checkout Golden Eagle for belt drive systems or Staton for chain systems. Friction rollers are simple and may work okay except when damp/wet.

I'm a fan of the Robin Subaru 4 stroke engines myself but Honda and some others do a good job with those too. Personally, I'd stay away from 2 cycle engines and always keep noise to a minimum.

btw - Motor is generally used for electric. Engine is what most of us in the hobby call gasoline powerplants.

 

[alfa1]

It has to get up to at least 70 for the flux capacitor to work!

oh stop it



















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