Can't it be adjusted here Bob or is yours different thinking

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I would have thought maybe a pair of long nosed pliers to hold the inner locknut then work on outers with open ended or split ring spanner. Even jamming tapered end of a plain screwdriver might work on inner.

Richard

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