Stage 1 GT-5 Top End Kit 66cc
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Stage 1 GT-5 Top End Kit 66cc:

This Stage 1 Engine Kit provides turnkey performance for your GT-5 motor. This kit will NOT fit the GT-5A, GT-5SR or PK-80 motors. The transfer ports are smoothed to reduce turbulence. 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.

Kit Includes:

  • Your choice of 5.3cc, 6.0cc, or 7.2cc chamber billet Stage 2 center fire cylinder head w/extra-tall nuts & flat washers *see note below
  • 1 Modified cylinder body (67.5mm face-to-face length)
  • 1 Modified GT-5 (Type-B) piston with rings
  • 1 Wrist pin set
  • 2 Thin aluminum head gaskets
  • 2 Base gaskets
  • 1 Exhaust port gasket
  • 1 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 or the crankshaft.
  • Torque head nuts to 80 inch pounds; do not over tighten.


  • Item #: BTKS1
  • Manufacturer: CR Machine
  • Condition: New

Stage 1 GT-5 Top End Kit 66cc

Price: $160.00
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