AJS & Matchless Owners Club

East Suffolk Section

Technical Tip (14): Testing a rebuilt gearbox

How do you check that a rebuilt gearbox is good?  Installing it in the bike and connecting to engine power could be disastrous so, to be safe, bench test it.  Mount the ‘box in the vice and prepare the test kit: cut a short length of garden hose and in one end insert  an engine stud or a bolt, securing it with a jubilee clip.  Attach a second jubilee clip on the other end of the hose and attach this end to the gear shaft and secure.  Insert the stud end into the jaws of a battery operated drill with variable speed and reverse.  You can now slowly drive the gears and change gear to test the ‘box, increasing speed as your confidence grows!  Should the ‘box seize up, the hosepipe acts as a flexible connection and takes the shock, preventing damage to gears.