Cylinder Shape

[nwi45]

Someone is interested in a PSI dome I am selling, but they said that they just bought a cylinder and it's octagon shaped and doesn't think my "round" dome will fit the cylinder. Every 250R cylinder top is the same, right? The domes from the different years are interchangeable too, right? So this dome should work with no problems on his cylinder.

[machwon]

Not having seen a PSI cylinder but in a picture, the bore sizes are much larger and will not fit. I'm sure the bolt patterns are different or larger just like the pro-x cyl as well.

[nwi45]

The dome was installed on a stock '89 cylinder previously when I had my R.

[Dave83]

I believe the old air cooled cylinders had the octagon head gasket.

[slamdak8782]

the round is for the stock bore heads. Octagon is for either a 330 or a 425r