The problems with a stock R cylinder with a big bore sleeve installed are, once you remove that much metal from the casting the jug looses some strenght + the head, where the studs go through is just to thin to begin with then you get movement, slite but still movement.
Only way I have gotten them to survive is with the use of Three Bond 1211 sealant & the Cometic fiber gasket. With this fix, still its just a mater of time before it leaks, but it is an amount of time. Some I have seen leaked as soon as the engine got hot.
Normally what has happend on mine, compression leaked past the gasket & then would build up higher presure in the cooling system & would blow coolant out into the holding tank. Crazy part, no coolant would get into the cylinder bore & once the bike was off & cooled down, the coolant would be drawn back into the radiator when restarted, crazy.
Cylinder porting starts at $250.00, thats to re-port one or one thats had no port work done at all.
Upper midrange to drag porting is higher because of more work involved.
The butchered cylinder, depending on how bad the porting is now, how the port work will end up. Could be some places I cant fix if its been cut to deep.
Neil
