I recently did the Australian National Veteran Run in Nuriootpa, South Australia. It was a fantastic event covering nearly 600km of quiet, good roads, and my '17 Douglas did the whole run with few problems.
However, I had noticed before I even started that it seemed to jerk every now and then in first gear when it was under heavy load. But this got worse, and on the last day I had no first gear at all, despite adjusting linkages etc.
When I got home, I stripped the gearbox. There was nothing significantly wrong with the gears, although the engagement dogs on first and third gear were both a little worn, (which can be expected). Those who know these gearboxes will know that the selectors move under quite a high spring pressure, and need to be held in gear by the gear linkage, so this has to be correctly set up. I replaced bearings, changed the dogs around etc. but could not find any obvious reason for a gear to jump out. Upon reassembling it, it was better, but still jerking in and out of first. But there is no gear noise (ie grating of gears).
I have checked everything on the rest of the drive system, tightened the drive belt and clutch, but the problem persists.
Does anyone have any ideas ? Suggestions would be appreciated.