Scooterotica

I have a 1966 li150 special with original spec gearbox. It's end ratio is something around 5.65.

The question is, should I just change sprockets to 17 and bring the ratio down to 4.94 OR swap to a indian GP200 gearbox with 19/46 sprockets.

The engine is being rebuild to a RT195 kit with some sort of good Clubman and phbl 25 delorto.

Any opinions on these?

I'd try it with std GP200 gearing first. 18 x 47 gives 5.2, it should pull well with that. If it runs out of revs then I'd try 19 x 46.