Yeah mine does seem pretty high
I've got an old Baotian engine (think its pretty much the same) will check the gears on my Kymco against the old Baotian ones to see if they'll fit.
Only ones i can see to buy are a 10% Gear up kit but are only recommend for 125cc's
EDIT:
Just an after thought, what size wheels does your bike have?
Mine has 14" which may affect gear ratios etc