Honda-SOHC

It's worth checking the hardness of the fork first Matt.

Just run a metal file across non toleranced surface of a knackered fork to see if it'll cut it.  It's usually the gear's that are heat treated material for obvious reason, fork's in many gearbox applications are only bronze.

A healthy gearbox would not routinely "run" the forks under load generally.  The gear is not side loaded when driven on these straight cut boxes.

If they wear as discussed above,  touching diagonally opposite faces on the pads, gear component making a mark further up,  then it would suggest the fork is bent such that it's not presented to the gear slot perpendicular/true.

If that's the case,  then if the dogs aren't engaged fully they can try to spit themselves back out of gear. This is usually obvious as the damage on the dog's noses gives evidence.

The original gears in this thread look like that's happened, you can see it starts to round off the leading/driven edge of the dog as well, making it even harder to stay in gear when loaded.

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Presume you've seen pictures with 450 from that era Ash,  Lord Lichfield and Britt Ekland apparently.

Happy new year to all forum members.

Hope you all have an interesting year with various projects. 

The red and black vehicle service book a friend has issued in 1979 for his 750 F2 which records original services from zero miles.

The official manuals have in them the detailed schedule to be completed at various mileage intervals,  may help in producing a current record for your bike.

https://www.ebay.com/itm/1972-1978-Honda-cb500f-cb500-Transmission-Gears-Shafts-Trans-Tranny/202527538479?hash=item2f2794fd2f:g:qggAAOSwolpcCUAz&redirect=mobile

Could be from same engine,  is it same supplier?

I think there's information that leads to conflicting opinion on this.

The Honda manual I have for 750 F2 is very specific in stating that the angled slot plate should be fitted as picture B in your early post.  it also has the double plate fitted to centre clutch pack.

As far as I'm aware the angle is there to manage oil dissipation as the clutch is released and so will affect the bite "feel" and how smooth the initial drive takeup is. It doesn't look like it will cause a problem as such when fitted either way, but it should change the operation in a small way but only for pulling away from a standstill.

If you look at how the clutch operates,  engine running,  clutch open, in first gear.  Then the metal places are stationary with the fibre plates rotating with the crank, and oil between each interlayer.
As you bring the clutch toward closing then it has to squeegee the oil out of the layers to gain traction and start to rotate the metal plates. This is then driving torque through the gearbox.

As the plate with the angle slots is approached by the flat plates either side of it, the oil has to be wiped into the slot for its exit route out of the clutch pack. If the slots face forward (as in A) then it has the effect of working against centrifuge, which keeps the oil in play longer, which gives a softer clutch bite. 
In the B plate scenario,  the oil is less retained against centrifuge,  so should give a quicker bite transition,  and potentially more difficult to modulate torque takeup.

They both don't seem technically wrong but should give subtly different initial affects.

I doubt that the affect is aimed at moving geachanges as all of the clutch pack is moving together after initial pull away. 

If you don't like the effect when installed, then it's easy to flip the plate.  It's more fine tuning by designers than any technical disaster if it's fitted backward.

The dog drive looks like it's been spitting back out from the look of the radius on those drive faces.

You need to compare them with a known good set to see how much they are worn. But they don't look disposed to staying in place under load. Don't think you could rely is on them even if everything else wash perfect.

If under load it's trying to separate the dogs it will heat up the selector fork as it'll be "leaning" on it which it's not supposed to do.

Is that back dog of the three sticking up a different size to the others? Can't get a good view of it in the photo, and is it supposed to be?