Topic: Surprise 812 Yoshi Pistons - but will they work for me

[PeWe]

I have 72mm gaskets for 71.25mm bore.
The only thing I had in mind was the very small increase of chamber volume.
Some gaskets are not perfectly round or not exactly centered. I grinded MLS gaskets for 70mm since they had a very little stick out into the bores.

So slightly larger bore ID in gaskets make it easier. Here only 0.5mm radius.

[HondaMan]

An 836cc gasket will work.

Thanks, I guess a 0.5 to 0.75 mm lip around the circumference won't affect flame propagation and combustion too much at 10.5:1 with good fuels. Cheers

Honda's own head gaskets will fit the standard bore and up to +1mm bore. The standard gasket leaves that 0.5mm space all around the chamber, usually. It's important to note: the pistons don't quite rise to the height of the head gasket, usually stopping about 0.25mm below the top-of-bore. This changes if the tops of the cylinders are milled, which I do to almost all of them when rebuilding (because of today's thicker head gaskets that can leak, otherwise), so then it pays to check.