A misfire and escaping compression:
a Triumph head-gasket diagnosis.

What I observed with the owner.

The motorcycle had a misfire. While examining it with the owner present, I could see and hear compression escaping between the cylinder head and cylinder. These were direct observations made during the inspection.

I identified a failed head gasket at that joint. The next question was whether further examination would reveal additional damage.

What a failed head gasket means.

The head gasket seals the joint between the cylinder head and cylinder. In this case, that seal had failed and compression was escaping. The misfire was also observed during the inspection.

For the owner, the useful distinction is between the fault identified during the inspection and any additional damage that would need further examination.

Why the limits of the finding matter.

A clear inspection account should separate what was observed, what was diagnosed and what remains to be checked. Here, the observations were a misfire and compression escaping at the head-to-cylinder joint. The diagnosis was a failed head gasket. The condition of the head and any other internal damage remained subject to removal and further inspection.