Zipper’s has developed these Stage III heads specifically for CVO 110 and 120R/ST engines to increase port velocity and the result is a huge power increase for these thirsty engines! This unique design delivers an awesome experience, with broad power for all types of riding. Installed on a 110 with Red Shift 657 cams, these heads put over 129 HP through the rear tire with a conservative 10.3:1 compression! Other high output applications are also available.

• Designed for balanced power applications with excellent peak power
• Zipper’s developed high-velocity ports
• Chamber volume 102cc with stock deck
• Performance valve springs for .660” lift standard* (*Optional springs available for higher lift applications)
• Requires high-dome pistons
• Requires larger throttle body and injectors
• Best quality workmanship and materials used

After 5-axis CNC-porting is complete, we install and size Zipper’s super-concentric ductile-iron Step-Lock valve guides. Valve seats are machined with specially developed proprietary seat angles to accept oversized stainless steel valves treated with severe-duty coatings and flow-enhancing shapes. When full-radius seat and guide machining is complete, the head gasket surface is decked for combustion chamber CC requirements and trued for best possible gasket seal. Lastly, viton valve stem seals are installed and performance valve springs are set up for your camshaft selection.

To unleash the power potential of this head, domed pistons and an oversized throttle body with higher flow injectors are required for any cable or TBW fitments. Contact us if you need assistance in selecting the proper camshaft, pistons and exhaust for your application.

Supply us with your piston volume and camshaft 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.

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.

*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.

Weight 1 lbs

Country of Origin

Engine Type


Customer reviews


There are no reviews yet.

Be the first to review “Zipper’s Stage III CNC Heads for CVO 110 & 120R/ST Engines”

Use one of the allowed file type: jpg,png.