I am a member of an amazingly useful site - The TZ Website. It has a great range of resources and knowledge. I am posting on the discussion board. If you are interested in Yamaha Racing Bikes go and look.
I'm not sure what the ignition is on this bike, if anyone can assist in ID on it I would be most grateful.
The Tacho has perished rubbers and is mounted on an angle, I don't know why but the previous owner set the redline at 14,500 rpm. Seems rather high, I'll have the crank rebuilt as I reckon that the bearings will be cactus if he has run it at that speed.