Honda-SOHC

If you take a length of brass wire (long enough so you can't drop it completely down the plug hole) you should be able to put it down the plug hole and as you turn the engine over gently on a spanner you can feel which direction the piston is moving.  Take off the rocker caps and watch that the inlet valve is opening as the piston goes down rather than when it is coming up.  The valve timing may look right but in fact could be 180 degrees out.  If someone has assembled it incorrectly a top end strip will sort it out.

As for the blank cases, a friend of mine bought cb350 crankcases new from david silver spares as his original ones were damaged.  The new part came without a number on it.

Has anyone sucessfully put a wheel with a twin leading shoe drum brake into a cb500/4 or cb550? and if so what did you use and how good is it?  I used to have a bike (cb350k) with a TLS drum brake years ago and it was excellent and would lock the front wheel if pulled hard which is something my current disc brake will never do.  I know it might seem like a retrograde step but i'm sure it could work.

Hurrah, I made it across the pond.  I feel all light headed now.