Honda CT70 Z50 108cc TB 108cc Big Bore Kit, V1 Race Head, & 26mm Mikuni VM26 Kit

TB Parts 108cc Big Bore Race Kit with V1 Head and Mikuni VM26 Carb

Wake up your stock Honda horizontal engine with one of the best bolt-on performance kits available for the Z50 and 3-speed CT70.

This TB Parts 108cc kit combines a V1 Race Head, 52mm big bore cylinder and piston kit, and a Mikuni VM26 carb setup to turn your stock engine into a much stronger 108cc setup without boring the cases.

The V1 race head uses larger 25/22mm stainless 21-4N valves, improved porting, a race cam, and better valve geometry to help the engine breathe, rev quicker, and pull harder through the powerband. Paired with the lightweight high-compression 52mm piston and proven VM26 carb, this kit delivers serious performance while still keeping the install straightforward.

No case boring required. Bolt it on, tune it, and let it eat.

Features

• V1 Race Head with 25/22mm stainless 21-4N valves
• 21mm intake port with oversized exhaust port
• Race camshaft and cam sprocket
• 52mm aluminum cylinder with steel sleeve
• 52mm high-compression lightweight piston kit
• Designed for 91+ octane pump gas
• 108cc top end gasket kit included
• Clutch cover gasket and center case gasket included
• Mikuni VM26 carb kit with ported manifold
• Includes carb gaskets, hardware, and throttle cable
• No case boring required
• Replacement parts available from Bart Moto Co

Fitment

• Honda Z50: 1968–1979
• Honda CT70 3-Speed: 1969–1979

Installation Notes

There are no printed installation instructions included. If you are comfortable replacing a piston and top end, this kit is a straightforward install. If you are not experienced with engine work, we recommend having a qualified technician install it or using a factory shop manual.

• A VM26 carb kit requires a compatible throttle.
• CT70 models require a dual-feed petcock to handle the two fuel tank lines.
• If using a stroker crank, use the correct 12V piston along with a high-volume oil pump and shaft.

Note

For use only with 1968–1979 Z50 and 1969–1979 3-speed CT70 engines.