YFZ450 ATHENA 478CC BIG BORE KIT
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YFZ450 ATHENA 478CC BIG BORE KIT
Ported and polish makes the air flow through the head with a higher velocity which means less stress on your motor and the easier it works the more power you feel in you seat. How much it costs depends on the machine shop you take it too but anywhere from 250 dollars to 500 dollars
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