Zipper’s Stage II CNC Twin Cam® SportMax Heads

Our Stage II CNC heads employ special high velocity ports developed specifically for riders in search of early torque with broad power. With ports designed for high-velocity airflow, matching these heads with the proper camshaft and exhaust produces amazing power. Perfect for riders of heavier machines who want great acceleration just by turning the throttle – no rowing of the gearbox and high RPM needed!

• Zipper’s-developed high-velocity port shapes
• Designed for early torque applications
• Works great with flat-top pistons, 95″ and larger
• Custom decked for your specific application
• Chamber volume – 85cc with stock deck
• Best quality workmanship and materials used

After cleaning, CNC porting and guide replacement, SportMax heads are fitted with high quality 7mm stainless steel 1.900” intake / 1.610” exhaust valves and beehive springs with chrome-moly steel retainers. Special valve seat machining and blending for a smooth transition to the ports is performed by our highly skilled specialists. Valve springs are custom-packed to handle valve lifts up to .580”*; head gasket surfaces are precision-machined to your deck requirements to ensure proper compression, absolute trueness and surface finish.

The Stage II CNC SportMax heads provide real results with a great balance of performance and value. These heads are designed for optimum results with the factory throttle body and injectors (lower cost!), maintaining high port velocity for best low and mid-range power. Contact us if you need assistance selecting the proper camshaft, piston compression volume and/or exhaust system for your application.

Processing time

Once the cores arrive at Zipper’s they are unboxed, and inspected for shipping damage. Then we review your job order sheet and other related documentation. Job sheets that have not been finalized before your cores arrived will take additional time to sort thru before the job is put into production. Once finalized, the cores will be disassembled, serialized then move into production. Turn around (Process time) varies depending on the time of the season and how long it takes to get your job sheet finalized. Because of the dedicated skilled labor at Zippers and the vast amount of capital equipment we get the work completed with the highest standard of quality with one of the best turnaround time in the industry.

Work is performed on your supplied head cores.

For our standard production heads Shop Time is approximately 15 business days (during peak season allow for additional time).  The below options will require additional time to process:

• • Custom Modifications
  • Custom Finishes
  • Require Thermal coatings
  • Needing Additional Repairs
  • Or other Non-Standard Work

Exchange heads may be available if the condition of your cores qualifies. The process to determine the condition of your cores is to ship your cores to Zippers for inspection.

You can also purchase heads outright (without supplying a core set). We will supply clean, reconditioned factory castings for your application – add part #517-015 to your order.

International Customers – Import duties are not required when to shipping your castings for modification. Special low shipping rates are available for your cores; contact your sales representative for details.

Supply us with your piston volume and camshaft selection for final cc volume through decking.

Remove heads from engine, wash off oil and ship to Zipper’s as-is. Improper cleaning methods can actually do more harm than good; we suggest you allow us to properly prepare your heads for modification. Extreme care is taken during our preparation process to preserve component finishes. A small cleaning charge applies to heads sent in for modification.

*To ensure you enjoy a premium experience, Please fill out a Build Sheet/Job Order Sheet prior to completing an order on the website.
Click here for Zipper’s Build Sheet/Job Order Sheet

Not legal for sale or use in California on any pollution controlled motor vehicle.
Not legal for sale or use on any EPA pollution controlled motor vehicle.