Kit Cylinder and Crankshaft Italkit 80cc c.43mm Derbi Variant Start 3

Cylinder and crankshaft kit Italkit 80cc 43mm stroke for Derbi Variant Start 3.

The Derbi Start 3 engine in standard form falls short when you really start to push it. With this 80cc Italkit kit, it extends the stroke to 43mm, increasing the displacement so that the engine revs higher and pulls harder at high rpm. The cylinder bore is 48mm and the piston has 1 ring: less friction, more rpm, with a 12mm wrist pin.

The cylinder head is two-piece, with a cover and removable insert, which allows you to adjust compression by changing the insert without having to machine anything. This helps to cool the combustion chamber more effectively. The crankshaft with a long 43mm stroke and 12mm wrist pin comes balanced to withstand the demands of an 80cc setup without vibrating or breaking the connecting rod under demanding use.

To get the most out of this kit, you need an exhaust that evacuates gases efficiently and allows it to gain rpm. The original carburetor is too small: fit at least a 19-21mm unit with its corresponding intake manifold. Do not forget to reinforce the clutch with stiffer springs and reinforced shoes, and fit a variator with lighter rollers so that the engine runs in its proper rpm range. Without these changes, the kit will not deliver even half of its potential and may even seize due to a lean carburetor setting or an insufficient exhaust.

Technical specifications

• Displacement: 80 cc
• Bore: 48 mm
• Stroke: 43 mm (long stroke)
• Piston: 1 ring, Ø12 mm wrist pin
• Cylinder Head: 2 pieces (cover + interchangeable insert)
• Crankshaft: Racing, 43 mm stroke, Ø12 mm wrist pin
• Kit ref.: K.12.581.G
• Engine assembly ref.: CK.12.580.G
• Cylinder ref.: CI.12.580.G
• crankshaft ref.: CB.12.5.43
• complete cylinder head ref.: CU.12.42
• insert ref.: CU.12.42.1
• Gasket set: VJ.12.11
• Compatible crankcase: Derbi Variant Start 3

Compatible models

DERBI

• VARIANT START 3