405 Big Bore Kit 999-026 Exch Cyl



405cc Big Bore Kit. 999 026 (Exchange Cylinder). All 348 Engine Variants.

For more information and to see the engine being assembled and then ran on the test bed click on the following link:


Kit comprises of:
405cc Nicasil Plated Cylinder

Sportax 405 Piston Kit. Includes Rings, Circlips and Pin

Base Gasket

3x Cylinder Head O Rings

If you wish to exchange your old 350 cylinder the total price for the kit will be £431.38 Saving you £152.75. The kit will be shipped as soon as your cylinder has been received.

Discount still applies even if your cylinder has been seized. All cooling fins need to be intact to receive the discount. Damaged fins can still be exchanged but a surcharge will be added.

Cylinders will be supplied in their bare metal finish and can be powder coated satin black for an extra £50.

Please email or call for further info regarding your new 405 upgrade kit.

Additional information

Exchange Item

Exchange Cylinder