Original cylinder rebored to 175 vs Rayspeed alloy 175 kit?

[Nerdy Norm]

Thanks, I'll take a look when I get home. From memory, I'm pretty sure that they are bigger on the alloy kit.

Regarding the heads, I think they're different. The alloy kit came with its own head. The head supplied by Rayspeed when they did the 175 rebore is a genuine SIL 175 head.

[Nerdy Norm]

Well, I checked the heads, and they are in fact the same (or at least they come from the same mould - one is slightly rougher than the other).

However, my decision was made for me - the helicoil insert in one of the exhaust stud holes in the alloy cylinder just spins, so it's impossible to tighten up the exhaust. I'll get it fixed at some point, but for now the iron cylinder is fitted.

With a bit of luck, I'll get it fired up this evening.

[EddieStone]

I prefer cast iron. The cheaper alloy stuff is too hit and miss.

[Nerdy Norm]

Tightened it all up and it fired third kick last night

Just need to set the timing and check the carb and I'm good to go ...