4 stroke reliability and parts availability / build advice

[Sidewinder Jerry]

What transmission would I need for a 15mm or 5/8 shaft

A 30 series CVT. There's an adapter so you can take it from 3/4 to 5/8

 

[Toby woodman]

do the bolt holes on the side of the engine match up?
also. with a 10 tooth sprocket the top speed would also be too fast

 

[Sidewinder Jerry]

do the bolt holes on the side of the engine match up?
also. with a 10 tooth sprocket the top speed would also be too fast

Here's the thread on how to attach the CVT to a small engine.

49cc 4-Stroke 30 Series Torque Converter Build

Thought I would share my first build as I have seen some conflicting info about using a 30 series torque converter with a small engine like with this 49cc 4-stroke. I did not document this very well, as this was done over 2 months. The bike has run perfect and has about 300 miles on it. You...

motorbicycling.com

Normally, a builder would put a CVT on a larger engine such as a 212cc then a small sprocket (10t) to a larger sprocket on the rear wheel (44t). Meaning only 1 chain is needed on the left side. This would give them a very drive ratio drive system.

The other option would be to put a centrifugal clutch on the 212cc with a 10t sprocket then run it to a jackshaft with a large sprocket such as a 30t. There would also be a second smaller 10t sprocket on the jackshaft that ran to a larger sprocket on the rear wheel such as a 44t. Meaning 2 chains are needed on the left side. This would be a fixed ratio drive system.

By combining a CVT with a jackshaft you can then use a small engine such as a 49cc. Meaning you'll need 2 chains on the left side. However, you'll have a varying drive system. It'll be like starting out in a low gear and automatically moving to a high gear as you speed up. As you begin to slow down it'll automatically return to a low gear. Currently nobody has a build like this.

 

[Toby woodman]

I'm thinking of putting an 8 tooth sprocket on a 30 series torque converter with a shaft adapter. can you see any reason why this wouldn't work

 

[Toby woodman]

this is on a lifan 152

 

[Sidewinder Jerry]

I'm thinking of putting an 8 tooth sprocket on a 30 series torque converter with a shaft adapter. can you see any reason why this wouldn't work

You have to understand reduction these engines can only be ran so low. Without enough reduction you'll destroy your engine by overloading it.

 

[Sidewinder Jerry]

this is on a lifan 152

I wouldn't run the 152 below a 16\1 reduction. If you want a varying drive system. Generally whatever you add to the top end; you subtract from the bottom end.

 

[Toby woodman]

 

[Toby woodman]

would this not work? I'm new to four strokes

 

[Sidewinder Jerry]

Had to get some coffee in me to wake up. The 152 isn't a very good choice of engines if you want some speed and hill climbing abilities. It'll take a total reduction of 9.28\1 on 26" wheels to do 30 mph on level ground. At only 3 horsepower this engine doesn't have a lot of power for the amount of rpm it produces. Unless you and the bike build are under a 150 lbs this isn't going to happen. A more practical speed for this engine is around 20~25 mph max.