My B44R has developed a weird shifting issue. Every once and awhile when going from 2 to 3 it finds a neutral but if I wait for a moment it clicks into gear. The shift feels completely normal. I know little to nothing about how the gear change mechanism works so its difficult to imagine what's happening.
I have boned up on the shift mechanism with the help of a parts catalog and 441rider (aka Steve Dale of Brit Gaskets) videos. I have been in 441rider's dingy shed come workshop so I understand why his videos look the way they do. I don't see anything in the shift mechanism or transmission that would cause the delay going into gear.
If your quadrant is not moving enough to move the camplate fully to the next notch/gear a good leaf spring will compensate and force the camplate to move so it can engage in the next notch on the camplate completing the movement. As the leaf spring loses its springyness it can no longer move the camplate and you will get a neutral.
I guess that's plausible but I would think the friction of the spring on the cam plate would stop the cam plate from moving at all unless helped along by the quadrant plunger. Its an intermittent problem that did not happen at all today on my 6.3 mile daily drive to Starbucks.
I grind down the high spots on the camplate where the spring runs and then polish the surface to a shine, this stops the leaf spring contacting the camplate about 1/2 way up the spring and improves the feel of the gearchange, before I do this the angle of the camplate is quite steep into the notch and if you are within 1/4 the leaf spring could complete the change, surface on new camplates is rough from the pressing die but used ones can be very smooth. Just be a bit more forceful for now with the lever and add it to the list on next strip down.
I have no idea what's in it but other areas seem to be stock. Its a 67. I'll keep your comment in mind when and if I take it apart. When I bought the bike in 08 I had ideas of doing a restoration but I'm used to the patina now and unless something breaks I'll leave it alone.
For what it's worth: I was having some shifting problems with my A65 the other day. It went directly from second to fourth, skipping third, then back down to second from fourth, again skipping third. I took it down to first and then back up through the gears. It found all four this time, but the next time I tried to downshift into third, it found neutral between fourth and third.
The problem, as indirect as it may seem, was that both my primary chain and final drive chain were loose. There was also no oil in the primary chain case, or at least none came out when I removed the drain screw. I had been checking the primary chain with my finger (engine not running of course!) - NG; you have to push it up and down with a screwdriver or the like. Brought it up to the 1/8"-1/4" free play, and added 140cc of ATF. I also lubricated and tightened the final chain.
Bottom line, after the adjustments, shifting is back to normal, snick-snick, smooth as silk.