The Secret Piston Page

These pistons measure 1mm lesser diameter on the top compared to the bottom. I have documented this with the last piston from the 535 Continental UCE. Technically I do not know why this is the case but if I had to venture  a guess I would say that the top has more thermal expansion than the bottom.

Based on the company’s official 86mm stroke the actual displacement based on the BIGGER DIAMETER (because that ultimately determines the size of the cylinder jacket) are calculated using this online app.

477cc real displacement

Top: 83mm (bottom 84mm) OEM piston from the Bullet 500 UCE – artificially “flattened” by us, the original has a 2.5mm groove which we cut off. But the diameter is unaffected by that. This piston has the same diameter as our 477cc upgrade piston made by Ducati.

432cc real displacement

Top: 79mm (bottom 80mm) “Ducati” made “450cc” piston which really gives 432cc in the Hima

411cc real displacement

Top: 77mm (bottom 78mm) OEM piston of the Hima LS410 engine

511cc real displacement

Top: 86mm (bottom 87mm) OEM piston from the Continental 535 UCE – This piston’s diameter is the same as the 510cc Himalayan upgrade piston from Ducati for our Super-Hima with modified head and engine housing.
Same as above, bottom side, 1mm thicker.