the 550s been getting smokey through the valve guides,i had a rebuilt head on the shelf for ages and a set of first oversize pistons/gaskets etc so i got my mate with a shop to rebore a spare barrel i had,today i chucked it all together.
check the oil soot on the old piston,they check out good piston wise but the old rings are right on spec limit.
two inlets were just kissing soot,i put this together from old parts 18 months ago and have been thrashing it since,it went better than a rebored 500 i built!.
id thrown it all together without a base gasket or those barrel o rings,i only wanted to run it to see how the transmission was,it went so well i made it my #1 engine!the no base gasket wouldnt have helped with the valve proximity though?
anyway its running again and i put 30 kays on it today,nothing over 5000 rpm for a couple of hundred kays,i havent even resynced the carbs i dont want to idle it,i can feel theyre off though low-off idle.
one tip,i polished the ramps that feed the rings into the cylinders before i gave it to my mate,it almost fell together,no screw driver nudging at all.