I am restoring a mid production CB750 K1 (10894xx). It came with a K3 or later die cast head and a cylinder block that is very smooth (diecast?). From Hondaman's book, the block is pre K3 due to the oiling passage O-rings. Tews provided me a KO block and head and as far of I can see from pics of Marc's K2 in his book the KO head is rough cast so the head should appear correct for my K1 restore. Should a K1 block be rough cast (like the KO) or a smooth die casting?
The block and head Tews sold me are in incredible condition, virtually no wear on the bores, guides, valves, rockers and shafts! I assume the valve guides are the stellite ones on early heads that Hondaman has been documenting in his rebuild thread. The KO head has no exhaust valve seals and tapered guides, the intake guides as later diecast heads.
Any help would be greatly appreciated!
