simple reason is that a series 40 -being a symmetrical setup- normally is mounted with an inboard driven, as opposed to the outboard driven unit of a asymmetrical series 30.
And, with an inboard driven unit, you can't just add a plate, since the belt would NEVER line up.
GPS sells a series40 kit with a steel backplate and a reverse spring to outboard mount the driven..
honestly, that sounds fishy to me, since no matter what way you look at it, at one point or another the belt will NOT be inline with both pullies.. (it can't be with a fixed outboard driven)
I think the main reason why GTC removed every trace of their attempt offering a TAV Kit with a series 40.
Aaanyways...
No, there are different backplates (basically two) one for low power low torque stuff (mini bikes up to 5hp mostly) which is a small bend steel plate, and the cast one you have.
Not mentioning the custom giant steel one GPS sells in their kit.
which is the ONLY one that should at least fit your engine.
I wouldn't use it at all, since a fixed outboard series40 driven is completely against
my strong beliefs...
but that might just be me...
'sid
PS maybe you should buy a different engine instead? you can always resell yours, can't you?
