More grunt for my ST50 - any ideas?

OK, first. I have an ST50 - am I allowed on here...? It's a 1972 jobbie with 10k miles on it.

Well, maybe I should be allowed on, because I'd actually like it to go more like an ST70.

It might be because my other bike is a Ducati, but nevertheless the little ST feels very flat, and really struggles to get to 30mph, even though it's obviously pre-restricted.

How do I add grunt? Get a bigger (72 or 75 cc) barrel? Will a C70 or C90 motor and box slot straight in? I don't want to be putting a Lifan in it because the plan is to take the bike to as close to original as possible across the board.

Any suggestions?

Iain

Can anybody recommended a site or owners group who can offer advice...?

Hi lian, good luck with making your st50 having more grunt, I have seen lots of owners of st50s on here and st70s and Honda chalys

Hi Iain
The cylinder and head off a 6v st70 or c70 will fit onto the 50 bottom end or as you said a c70 complete engine of the same era will fit just the same .
Graham

Maybe a TB Parts 88 kit would fit?