Apparently the MT75 gearbox uses an odd synchro hub arrangement on 1st and 2nd gears which may explain selection issues. TM thread here plus downloadable pdf on gearbox overhaul here might provide some insight.

Richard

2018 Roadster 3.7
1966 Land Rover S2a 88
2024 Royal Enfield Guerrilla 450
1945 Guzzi Airone