Check the clutch basket 'fingers' for wear. They get notched and stop the plates releasing properly once it's spinning.

The PV's won't account for petrol in the exhaust. You sure it was petrol?
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MC21SP Plaything
BMW F800GS Bumblebee
Triumph 9551 Daytona Big boys toy
FJ1100 Sporting relic
GTS1000 oddball