Stage 2 PK-80 Top End Kit 80cc:
This Stage 2 Engine Kit provides turnkey performance for your PK-80, GT-5A, or GT-5SR engines that use a 40mm stroke crankshaft. This is not for the GT-5 Skyhawk. The cylinder body features additional widening of intake and exhaust ports. Transfer ports are smoothed to reduce turbulence. Our special intake plenum is fitted and port matched to the cylinder body. Maximum power is achieved when the engine is connected to a good expansion chamber style exhaust system. The cylinder has also been specially prepared to allow the use of two different gasket combinations: For more low speed torque, use 1 base gasket and 2 top gaskets. For more high speed power, use 2 base gaskets and 1 top gasket. The ample cooling capacity of CR Machine’s cylinder head will not only allow greatly increased output, but will also extend piston and cylinder life.
- Your choice of 5.3cc, 6.0cc or 7.2cc center fire billet Stage 2 cylinder head w/extra-tall nuts & flat washers *see note below
- 1 Stage 2 hand ported cylinder body (69.5mm face-to-face length)
- 1 Special intake manifold plenum with 3/4" spigot (fitted and port matched to cylinder body)
- 1 Modified high-performance (Type-A) piston with rings
- 1 Wrist pin set
- 2 Top and 2 bottom gaskets
- NGK B8HS spark plug
*For engines using race fuel, use either the 5.3cc or 6.0cc chambered head. For engines using normal pump fuel, use either the 6.0cc or 7.2cc chambered head. This is only a rough guide; optimal results are usually gained through your own experimentation.
Set up the engine so that when the piston is at Top Dead Center, there will be a .010"- .040" clearance between the piston and cylinder head. A tight squish clearance will produce the best combustion efficiency.
- Before fitting the spark plug, gently rotate the engine to verify that the piston does not hit the cylinder head.
- Torque head nuts to 80 inch pounds; do not over tighten.
- Item #: BTKL2
- Manufacturer: CR Machine
- Condition: New