I have been led to believe the same,and Si if you mixed up Castrol 747 in the last 20 th century when you tried to start your bike all those years ago I would recommend draining the tank and use some fresh fuel,
Ian hows the 21 going ? have you put many miles on it ?
And Si hope all is well in your world might see you at Donnington soon,
All the best to both,
jonmac
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John