Heres what I posted in another post aaaages go...
All figures are piston complete with rings, wrist pin and circlips
HRC F3 piston : 162g (no it wont fit a stock crank)
MC21/28 piston : 201g
Tyga 300 piston : 227g (yes it will fit your stock crank, no it wont fit your stock bore).
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If I have to take the carbs off once more...