Mine didn't have a restricted boss drive when I bought it, but I've heard that you have to buy the new one without the weld on it.
And if the exhaust has an emissions tube then that will slow you down too. Not many had it, but mine did.
Derestrict that variator, make sure your exhaust isn't with the extra tube on it, and even with the stock 8.5 weights, if they're not destroyed, you can be getting 45 plus.
@hieumait, how many miles on it?
I would suggest taking some time to read the threads in this section of the forum and seeing what many of us do with our s9s. Another great place is the 49ccscoot forums. The tech section there is very nice and a lot of people there can help you if you give them the proper information.
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