here's a pic of my tubes from Forking by Frank's. They are 2" over in length. I figured since I'm droipping to a 17" front wheel, I might like to restore some ride height. They will also carry a little more air as I'm using period air caps. Chromed all the way up.
But back on topic, the Honda XL250 dirt bike dust covers fit perfectly
except for this gap.
The dust cap will move up and down in that groove, but it won't come out. Remembering that the diameter of the K0/K1 leg is less than that of K2? or certainly K3 and above, where the F models would fit perfectly.
Brainstorming, I figure if no one comes up with a better match, I'll wrap the top of the groove with a braid of safety wire or something thicker like copper wire. Then when the rubber dust cover pops over it, the cover should stay at the bottom of the groove, hence no groove showing.