Topic: Weber + ARD Mag setup no start issue

[valt]

That does not explain broken oil rail.
Pistons are JE?
They use thin oil rails that demand really careful assembly of cylinder, if not rail WILL fail.

Is the bore really displaced, not only the beginning of bore?

You need new sleeves or another cylinder plus another shop that can do it properly.

No the pistons that failed were 850cc CycleX pistons. I don't know if the bore is straight or not since I didn't take the sleeves out to measure them but the shop that has them is going too. I also brought him a set of stock bore jugs and sleeves so he can use those sleeves to bore out in the painted jugs. I think what likely happened is I messed up a oil control ring getting them in since as you can see even on the thick side there is barely any chamfer.

[PeWe]

Those rails are relatively thick, the non chamfer make it difficult and begging to snap any of the rings.

Test that oil rails are possible to compress competely before assembly next time.
The inner end corner can hook into the expander.

Test assembly when head is on the bench.

I had to file the inner edges on very thin oil rails that happily hooked into the expander.

Those 849 pistons are not available anymore, right?
Last trick to reuse a worn 836 cylinder.  Not much surface to chamfer when sleeve is only 1.25 mm thick.

I have a set of new 849 pistons (old piston design of the early 70's) and fresh bore of my old 836cc cylinder.
Pistons found cheap on eBay and my old cylinder could be ready for another round.