Big Bore Kits

Stage 1 88cc Big Bore kit for 88-99 Z50, 2000-2020 xr and crf 50's

- Lightweight aluminum cylinder with steel sleeve
- Cast in mounts on cylinder for aftermarket skid plates
- Oversized cooling fins on cylinder for efficient heat dissipation
- High compression 52mm piston with rings, pin, & clips (can still run pump gas)
- Head gasket kit includes all gasket needed to install bore kit.

Stage 2 88cc Big Bore kit for 88-99 Z50 and 2000-2020 xr and crf 50

- 20mm Carburetor kit

- Performance camshaft
- Lightweight aluminum cylinder with steel sleeve
- Cast in mounts on cylinder for aftermarket skid plates
- Oversized cooling fins on cylinder for efficient heat dissipation
- High compression 52mm piston with rings, pin, & clips (you can still run pump gas)
- Head gasket kit

Vintage Stage 2 88cc Big Bore kit

- Fits 1968-1981 honda z50, ct70, atc70, trx70, sl70, xl70
- 20mm Carburetor
- 52mm Piston and cylinder
- Lightweight aluminum cylinder with steel sleeve
- Cast in mounts on cylinder for aftermarket skid plates
- Oversized cooling fins on cylinder for efficient heat dissipation

88cc Race head kit for Your Honda 50 or Honda 70. This kit will drastically improve your overall performance on your bike. A stock honda 50 puts around 2.2hp to the ground and this kit will put you between 5.5-6hp to the ground and 30% more to the crank! Kit comes with fully assembled race head, performance cam, 20mm carburetor, and all the other goodies needed to fulfill your need for speed!

50 Caliber Racing Race Head, 88cc Big Bore kit, and 20mm Carburetor

Our Race Head has been updated for even more performance! It now has 25/22mm valves with better porting/flow. We also kept the combustion chamber the same size and changed the angle of the valves slightly. This will really wake up your stock engine and is comparable in power to the much larger Chinese 124cc engines!

Stroker Kit 1

Ready for more power? Convert your 88cc Race Head kit into a 108cc stroked out beast!! (Much more powerful than any of the chinese engines up to 125cc)

Complete 108cc Stroker kit for Honda crf and xr 50 and 70cc engines 1988 to current. Kit includes piston, race head, cylinder, cam, carburetor, throttle cable, gaskets, intake, crank, and filter.

Honda Trail Bikes Heavy Duty Auto Clutch kit. This clutch is a great improvement to your stock clutch. We recommend this kit with any upgraded/big bore motor. The stock clutch is designed for a stock motor and that's that. If you want reliablilty and power this is a must have performance upgrade. Fits 1992 to current year models. z50, xr50, and crf50

52mm (88cc -108cc) and 54mm (117cc) Head gasket kit

Left and right case gaskets for Honda 50, also fits all 50-125cc honda clone chinese engines.

47mm 70cc Head gasket and clutch gasket kit for Honda 50 and Chinese Lifan motor.

47mm or 52m head gasket kit

Performance Intake for stock head or race head

High Volume Oil Pump - Vintage Honda Z50 

High volume oil pump for vintage Honda pit bikes and small ATVs. Delivers up to 3x the volume as the stock pump. We highly recommend upgrading your oil system when installing a big bore kit. Installation requires 2mm drill out of oiling outlet. 

High Volume oil pump for 1992 to current year Honda xr and crf 50. Fits all years of xr and crf, Delivers 3 times the amount of oil over stock pump.

50 Caliber Rev Box. This rev box will remove the stock rev limiter and allow your pit bike to max out its performance and rpm's. Improved timing curve. Great bang for the buck! Fits all years of Honda xr50 and crf50

5 Pin CDI rev box

50 Caliber Racing 52mm Gasket kit for 110cc and 125cc Lifan Engines Pit Bikes Atv Pocket Bike Go Karts and Mini Choppers

50 Caliber Racing 47mm Head Gasket Kit for 70cc Pit Bikes Atv Pocket Bike Go Karts and Mini Choppers

50 Caliber Racing 52mm Head Gasket Kit for 110cc and 125cc Pit Bikes Atv Pocket Bike Go Karts and Mini Choppers