Huasheng 5/8 straight shaft engine clutch options

[ThatOtherGuy]

I'm interested in an engine with as narrow width as possible. I don't like the wide crank sets. I've built a 2 stroke before and that was fine.

I'd like a 4 stroke option but want to keep width to a minimum.

There is a Huasheng that is available with a 5/8 straight shaft and was thinking a standard gocart/mini bike clutch seems like it would work. Such a clutch with the drive gear inside would (if possible) would allow the most compact width as far as I can tell of any option.

Thought I'd ask if anyone here has done that or knows of it being done or knows it could be done.

Any other options that could reduce width?

Remove recoil starter and?

 

[wrench]

I'm interested in an engine with as narrow width as possible.
I'd like a 4 stroke option but want to keep width to a minimum.

If your talking 4 strokes
Whizzer motorbike 138cc 4t side valve engine is the most compact because it's purpose made to fit in a bicycle frame

But buying a complete Whizzer or building a Whizzer M/B from scratch is gonna be alot more $$$$ than a Huasheng M/B Kit

 

[ThatOtherGuy]

What about a used/NOS whizzer engine. Could that be had? What are they're HP, reliability and ability to use chain/sprockets?

I take it that the bike in the photos is you're bike. Looks like plenty of HP if you're doing 50mph for my purpose.