Welcome Porter!
No problem you posting the question in the wrong forum..
I just move it where it belongs
The reason for different size TCs is fairly simple..
the more power you through at them, the beefier they need to be.
And for a 3.5hp mini bike you wouldn't want to carry the weight of a Full scale salsbury TC
capable of handling upwards of 100 horses costing easily upwards of 700 dollars.
eating away most if not all the engine power..
and while those are the extremes..
it does make sense to differentiate task and poewr in a much finer grain
to get the best possible TC for the lowest possible price with the lightest weight.
So yeah, a series 30 is usually meant for up to 8hp engines.
(albeit some earlier manuals claim 13hp max.. )
The reason you want a series 40 is the wider and taller belt mostly,
the more contact surface the belt has, the more reliable it can transmit power
and the more power it takes to get the system moving... (hence the size differences again)
Series 40 clones on ebay luckily aren't too expensive these days anymore..
I think they're even cheaper than the series 30 clones were just a few years ago.
So not too much of an issue.
BUT I'd love to see a Pic of your TC first..
since chances are you had a series 20 (which is actually a KART part, whereas according to Jim from maxtorque series 30s are intentionally built for mini bikes)
instead of a series 30, and then a series 40 is a great alternative anyways,
reverting back to original setup mostly.
Or you might have a series 40 installed already that has been sleeved to fit a smaller 3/4" shaft enigne before..
in which case you do not need to swap anything.. just clean/lube and go
'sid
