Forum

[Presto]

PS - 3.5 - 4 thou for a 350 Bullet with 'straightforward' replacement piston [you know what I mean by that!].

[papasmurf]

The problem with using the piston manufacturers figure is that it will be too tight compared to the Royal Enfield workshop manual figure.

[Presto]

The manufacture's sizing will be correct if the piston is intended for the RE engine it's being fitted to. But if the RE sizing is greater than the manufacture's then you can take your pick. All I'd suggest is that you don't decide on a piston to bore clearance by wind direction and time of the month!