Currently assembling the engine on my DT2. I'm having issues with the gear selector.

The selector drum selects  gears nicely when turned with a screw driver in the phillips screw on the
end.
However, the selector forks don't want to play ball when fitted, not wanting to rotate the drum.
The claws seem very wobbly on their spindle and don't want to engage properly with the pins on the drum to grab them.

Any info on the wear areas that will cause problems with the DT2 mechanism?
Attached is an image of the mechanism. 
Thanks

When I'm in that deep I replace all the parts with NOS. Over the years and miles the wear and tear on the splines of the shaft and all the subsequent moving parts adds up to cause sloppy shifting.

Also the transmission doesn't shift very well unless the engine is running and everything is moving. You can try to simulate that by having someone spin the rear wheel or clutch basket while you work the shifter. Remove the spark plug if the clutch is installed. I try to make sure the clutch and shift mechanism works before installing the right side crankcase cover.

Never seen a problem in that area & so long as the spring is pulling the claws onto the pins [which appears ok] then i'm out of ideas.
Then again, have you got the plunger & spring fitted in the left side underneath.
If not then the selector drum won't stop in the right place for each gear so the claws can pickup the next pin.
When that [plunger] is in place you'd have hard job turning it through the gears with a screwdriver.
Also going through the gears on the bench or without it running requires turning of one shaft & only a little is required to get the dogs to find their mate & go fully into gear.
All a guess on my part but i know the system well on those.

Don't loose that circlip i can see lying there. I'm sure ya onto it. Just saying.