• Fits 47mm piston engines with 8mm studs.
• High Compression 5.1cc Chamber
• Large Copper Squish Band to prevent detonation
• Dual B7HS spark plugs
• Compression Release

Now that I am starting to settle into my new Houston, TX location, I am starting to liquidate items from my large stash of special Motorized Bicycle parts. Many of these parts I will be selling are not to be compared to the cheap Chinese copies of my work. CR Machine only makes high quality parts, and the stuff I sell is good stuff. I only sell good stuff.

Come and get the Compression Release Heads while they are available. 

These Check Valve equipped Compression Releases allow you to use the engine for effective braking.

5.1cc Chamber good for track conditions (stop and go); not for long high speed runs with advanced engines (unless running alcohol).