ZIPPERS PERFORMANCE BIG BORE KITS 124" HARLEY TWIN CAMS 99-17

ZIPPERS PERFORMANCE BIG BORE KITS 124" HARLEY TWIN CAMS 99-17

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These cylinders, when used with our 4-5/8” stroker crankshaft, increase displacement to 124”. Complete kits include cylinders, forged flat top piston kit, head and base gaskets. Requires case boring (instructions included) and stroker piston cooling jet kit. These cylinders are .183” longer than stock and require a wider intake manifold. Fits in all frames.

These cylinders, when used with our 4-5/8” stroker crankshaft, increase displacement to 124”. Complete kits include cylinders, forged flat top piston kit, head and base gaskets. Requires case boring (instructions included) and stroker piston cooling jet kit. These cylinders are .183” longer than stock and require a wider intake manifold. Fits in all frames.

Zippers 4-1/8” bore cylinders allow the Twin Cam® owner the ability to increase their engine’s displacement with the largest bore you can safely fit to the stock case. These are completely new aluminum cylinders, cast around a .240” thick iron liner, 60% thicker than the stock cylinder liner. This thicker liner reduces twist and flex in an aluminum cylinder, providing a very stable bore for the rings to maintain seal. These cylinders can be ordered with the bore undersize for final fit by the purchaser, or sized by Zippers with our 4-1/8” big bore pistons. Top them off with our CNC ported TC cylinder heads, for a complete top end performance package. Installation requires engine disassembly for case boring (a service available from our machine shop). Cylinder/piston kits include head and base gaskets (cylinders-only do not include gaskets, order separately). Available in as-cast aluminum finish or powder-coated black with machined finsh.