My Goal

I am confused. Are you putting a weedwacker engine on the bike, or a honda friction drive? you mentioned both in your op. you also mentioned a chain drive system as well as a gear to your back tire which would indicate the use of a friction drive. so which is it?

PureWirez said:

So, I'm assuming I need afree whee kit for my back tire, a centrifugal clutch for the engine, and sprockets wuth the correct gear ratio in mind. Am I missing something or comepletely wrong here?

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Your idea works with a mini bike with tiny wheels but ....

You need a jack shaft or gearbox to get enough gear reduction to the
back wheel for a 4 stroke setup like a Honda 50 cc with 26" wheels.

A lot of 4 stroke info on this site so start reading the 4 stroke engine forum.

There is a good 3 ratio gear calculator available to help you out too.

I've wanted to motorize that bike before. Steel frame seems solid and it looks good.
Although Personally if I did a new build on that bike I would..

Replace the throttle, boot+wire, spark plug, rear wheel, tensioner, exhaust, gas tank, fuel filter, valve, and take apart the top end.

But that's just me. If I was gonna make a daily rider that is.

It's probably just fine. Im just a pessimist with the kits. I think you're better off clamping to the frame but im not sure, maybe it would work out with no problem.
there's a fair amount to learn about these engines or kits. I'd say the most important may be to either get rid of the tensioner or keep a close eye on it. They're known for falling into the spokes of your rear wheel while you're riding.
I think Al. Fisherman has a great write up that if you follow it you'll have a great reliable bike. can't find it right now though, phones are clumsy.

I wouldn't know what to do if that happened to me. Anyway, a weed wacker will work but those use pretty darn small engines. If anything, they are typically mounted as a rear rack.
If you plan on commuting on the bike, you can do that but it'll only provide you with pedal assistance. I don't think a weedwacker will pull you without assistance. Not above 10mph at least. Idk what the cc is on yours in particular though.

Have you looked into the happy time engine kits? They can give you a solid grasp on how to build up your bike succesfully and then upgrade the parts from their. My bike has been running great. I would like more power, but all I need is to tune my carb and put a expansion chamber and I'm sure it'd get to 30-35

My personal opinion on building a daily commuter would be to use either a known reliable 2 stroke like a tanaka engine or a morini(thatsdax.com gp50 works too). That's not to say the china kit engines can't be reliable, they are a luck of the draw in most cases. Again, you can make them reliable but they won't be that way out of the box unless you're lucky.
If you do end up building up your bike, I'll be very curious as to how it turns out. Keep the camera handy

A 31cc friction drive will pull me around without pedaling until I get to the hills and I weigh around #210

I think you need to start with deciding what engine you want. I don't have experience with anything but the china girl right now so I probably couldn't help much with any other motor and how to mount it.