Bummed to hear of another F3 engine with shifting issues.
I hope its easier than finding you have a bent shift fork
I'm still without 5th
I rode for an hour last Sunday. Bike runs perfectly, but when I upshift from 4 to 5, there's nothing there. No gear teeth chatter, no restricted lever travel, nothing. I just get revs after I let the clutch out.
I even pulled over and lowered the shifter lever a notch from where my foot likes it. Still, nothing. My clutch works as it should.
Back in the garage, I can rock the rear back and forth and get all gears, including 5th, to engage.
I took the shifter cover off and checked the birdcage and shift linkage. Its all there and again, it shifts fine into ALL gears.
I'm about ready to bribe/challenge some of the PNW'ers with beer and brats to ride on up and help me figure it out
Let me know how yours goes. This might help...