This is a completely rebuildable stroker crank (3mm additional stroke) turns your mild mannered 250cc motor into a 263cc trail shredding monster! OK, maybe not, but sure makes it a fun machine.
Want the COMPLETE package? Order a Big-Bore kit to go with your stroker! That will give you a 308cc ripper! That is 24% larger than the stock 250. This package includes the Athena Big Bore Kit plus the 3mm Hot Rods Stroker Crank with new Genuine Yamaha crank bearings.
You will need to tune your EFI with something like the Power Commander V to get the most out of your Stroker kit.