Of the gears, this was the only one I was concerned about:
http://forums.sohc4.net/index.php?action=dlattach;topic=126735.0;attach=246876;imageThis is the C5 gear, the first one out of the countershaft hole. It's mate, the C2 "female" side, has slots to accept the dogs. I see some real shiny rounded edges on it in the photo (hard to tell from pix unless they are close-up and well-lit), and this one is the worst in these gearboxes.
The way to tell if it has an issue is: look closely at the dogs to see how far they engage to the mating gear. It must be 3mm MORE than the rounded edge, or it will have a tendency to jump out of 2nd gear when hot and under power.
The "cheap fix" back in the day was to set the C2 (female) gear flat on a mill and touch up the working edges of the 3 slots to a nice 90 degrees on their working edges, to reduce their taper. This taper is what tries to squirt the dogs back out of the slots under power, especially if the inside of the C2 gear is worn a little, letting the gear tilt away from the C5 dogs when under power. The more complete "fix" is to have the slots back-cut in a slight taper and the dogs similarly tapered to match. This method was called "pull cutting" back then, as you needed to only partly engage them and when the clutch was let out it finished the shift itself. For racing, this was a must past 10k miles or so, but for street use, not so much. It can tend to make the shifting notchy, especially when cold.
In the end, the worst that can happen with badly rounded dogs here is: you may find the need to 'skip' 2nd gear on occasion. I know many 750 riders (tourer-commuter) who did this for years after they bent the L fork in a street contest, but didn't want to tear it all down to fix it. On my own 750, when I got the new oils w/o zinc in them (since 2005 or so), I had to do this in 100+ degree days of traffic myself, even though the dogs on mine are not very worn.
On the flip side, I've also seen round-dog gears that were "fixed" by installing a straight (or re-straightened, but not by me) L shift fork, as the new fork just inserted the gear dogs deeply enough that it passed the rounded edges. This is an adequate fix, even at that. Often the L fork gets a bit bent and begins the whole rounding process by inserting less than 3mm of dog: just check yours with the cases open to make sure the dogs are fully meshing when 2nd gear is being made.
It's pretty easy to measure the mesh depth: spin the C2 gear by hand while slowly turning the drum, until the dogs begin hitting the slots. stop and note the distance between the gears. Then finish the shift and measure how far the C5 continued to move: that's the total insertion depth. Then, estimate the dogs' rounded edge depth (like, 0.5mm or 1.0mm) and subtract that from the total insertion depth. If you get less than 3.0mm mesh depth here, they need some help to be solid.
