I have bored the restrictors out in the past, you don't even need to disassemble the TB's to do it. (just clean the h*ll out of everything when you're done) Problem is it doesn't make all that much power diff. from what I have seen, on stock-cammed, stock-valved 853's anyway. Maybe a couple hp up top. Those stock tiny little valves and low-lift cams are the roadblock.
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