Italkit Cylinder and cylinder head 74cc Derbi Variant Start / Start 5 d.48mm c.40

Cylinder and cylinder head 74cc d.48mm stroke 40mm from manufacturer Italkit for Derbi Variant Start / Start 5.

This Italkit 74cc engine kit is the solution for those looking to give their Derbi Variant Start or Start 5 more power and allow the engine to rev higher without getting into machining work. By moving to a 48mm bore, you increase the displacement while keeping the original 40mm stroke crankshaft.

It is necessary to replace the original cylinder when you notice the bike has lost compression or if you want extra power for smoother riding. This kit is made of aluminium with Nikasil coating, a material that dissipates heat better than iron and reduces friction, preventing seizures and ensuring the engine runs at a stable temperature even under high RPM.

The design with 6 transfer ports and the exhaust port with 2 venturis improves chamber filling, achieving more efficient combustion and a much fuller throttle response across the entire range. In addition, it includes a special two-piece cylinder head that guarantees a perfect seal and perfect alignment thanks to its integrated guides, preventing gas leaks and ensuring that the explosion force is fully utilised.

For maximum performance we recommend fitting a larger carburettor, a reed valve and an exhaust.

Technical specifications

• Displacement: 74cc
• Bore: 48 millimetres
• Stroke: 40 millimetres (original)
• Material: Al-Si aluminium alloy with heat treatment
• Coating: Nickel-Silicon (Nikasil)
• Porting: 6 transfers and exhaust with 2 venturis
• Piston: 2 high-quality rings
• Cylinder head: Two-piece with centring guides

Compatible models

DERBI

• VARIANT START
• VARIANT START 5