Well, this has got me stumped.
Std GP200 engine on a Spanish case. All gear select with no issues, but 4th jumps out and won't stay selected.
Cables all seem okay- not too tight, not too slack
Selector arm at 90 degrees in 2nd and has about 3mm gap between the tip and the shock support in 4th.
Selector swivel arm isn't fouling on the nuts
Headset end is fine, no issues,
Pulled the gearbox out (end plate float checked and that's ok- all nuts torqued correctly)
No shavings or metal dust in the oil
No marks on the casings to point to wishbone rubbing
Wishbone held in with a dome cap nut, no wear on that
4th gear meshes with the Xmas tree perfectly, and the gear itself looks great, no wear or missing teeth
Swapped the sliding dog (it was a new SIL item). Replaced it with an Italian one. Problem seemed to go away, then 40 miles later its back and worse.
Pulled the gearbox out again and double checked all of the above. No signs of an issue.
So before I pull it apart for the 3rd time.....
Any ideas?