Sherco Piston Kit - 290cc

Genuine Sherco 290 piston kit, suitable for Sherco 290cc trials motorcycles. Available in four piston grades (A, B, C and D) to accommodate different cylinder bore measurements.

Each kit is supplied complete with piston rings, gudgeon pin and circlips, providing the essential components for replacing a worn or damaged piston during engine maintenance or a rebuild.

Piston Sizes & Part Numbers

Size A is the smallest piston and is commonly fitted from the factory, although this can vary. Each subsequent grade increases in diameter by 0.01mm.

The piston grade is marked on the crown of the piston to help identify the correct replacement.

Technical Specifications

• Recommended piston-to-cylinder clearance: 0.027–0.037mm
• Gudgeon pin diameter: 18mm
• Gudgeon pin length: 52mm
• Gudgeon pin centre to piston crown: 29.1mm
• Overall piston height: 68mm
• Piston crown edge height: 4.5mm
• Approximate kit weight: 328g (including rings, gudgeon pin and circlips)

Choosing the Correct Piston Size

Selecting the correct piston grade is essential for maintaining the recommended piston-to-cylinder clearance.

Cylinder wear is not always uniform, so we recommend measuring the bore at multiple points along its length and in both directions before selecting a replacement piston.

Pistons are manufactured with a slight taper and oval profile to accommodate thermal expansion during operation. For accurate measurements, the piston should be measured front to back, 19mm above the bottom of the skirt, at approximately 24°C.

Important: Some 2011–2012 Sherco models were originally fitted with a 75.965mm piston. If your existing piston has this measurement stamped on the crown, the cylinder should be measured carefully before selecting a replacement. A Size C piston may be suitable depending on the cylinder dimensions.

Compatibility

Suitable for Sherco 290 trials motorcycles.

Some original Sherco pistons feature a small half-moon cutout on the inlet side of the piston skirt, while others do not. Replacement pistons may be supplied without this cutout.

Please Note

Always check your existing piston grade and cylinder measurements before ordering. Moving to a larger piston grade without accurately measuring the cylinder may result in incorrect running clearances.

If you’re unsure which piston size you require, please contact Road and Trials for advice.