The Carbtune II is a two or four column mechanical manometer for vacuum carburettor or fuel injection throttle body balancing of two, three or four cylinder engines. It’s a basic, simple to use and long lasting tool which will save you pots of cash over using a shop for balancing duties.
You can buy a new version of course, but if you’ve picked up one of their older obsolete models up from a car boot, the small ads or (as happened to me) been gifted one by a retiring biker, you’ll likely need two things: replacement rubber tubes, which go very soft with time and can visibly pulse during balancing leading to lazy balancing rods (don’t forget to reinsert the dampers in the tubes when you replace them) and the instruction manual.
As Morgan have now updated the Carbtune II to the Carbtune Pro, their website shows comprehensive instructions for the upgrade model which is largely similar and can be more or less followed for the older obsolete models. But if you wanted to have a look at the original Carbtune II instruction manual as supplied, here it is:
(No copyright breach intended! This is an aid for owners of older Carbtune models)