AJS & Matchless Owners Club

My gearbox engages first and second with no trouble, but initially will not engage third or fourth. The gear pedal feels as if there are not other gears there. After a few hundred yards, third and fourth magically appear, and engage freely, until downward changes that is. Then they disappear again until I have traveled a little distance, then they are back. I have made sure that the spring on the outer case is the right way up, so any ideas would be welcome. I also have a very heavy clutch. The plates and springs are all new from the spares scheme, as is the cable. I have checked the cable run, and there are no nasty bends. Compared to my G3LS clutch, I need to get to the gym to be able to ride the Model 30 comfortably. It is truly horrible in traffic.

Any ideas?

Mike