Stage 2 [6.0cc]Cylinder Head 66/80cc:
CR Machine’s latest and most copied head design for the 66/80cc 2-stroke motorized bicycle motors using 8mm studs. If you see a similar looking head from another vendor, it's a copy of the Fred Head. I have lowered the price of this popular design to compete against the vendors that have sent the Fred Head to China for cloning. Vote to keep Americans at work! Buy the Fred Head! It is designed for moderately advanced engines using pump fuel, or can be using on highly advanced engines if racing fuel is used. If you have a bone stock or mildly advanced motor, look into the 5.0cc chamber Fred Head for better performance.
NEW!!! Choose thread type for the head nuts! Fine pitch (1.00) or coarse pitch (1.25).
Please be aware that in order gain the maximum benefit from this cylinder head, you will need to bring the outer edge of the piston to (or close to) the top of the cylinder. A close "squish" clearance has better combustion efficiency. If you have a GT-5 engine, using a shortened cylinder body will produce optimal results. Check out our cylinder bodies and complete top end kits for the GT-5 engine.
The increased cooling capacity of this head will extend the life of your piston, cylinder and engine bearings. The excellent cooling and squish band technology which this head utilizes will prevent detonation which is a main cause for overheating. Detonation also causes pressure spikes which puts additional strain on the engine bearings, causing premature bearing or crankshaft failure.
Coarse thread cylinder head nut torque spec: 60 inch pounds
Fine thread cylinder head nut torque spec: 48 inch pounds
Add a top gasket for an additional $4. Add a spark plug for an additional $4.50.