Honda CB750 FA - The bike looks cosmetically great but has come in as a non runner that hasn’t been started in years. When we did eventually get it started it ran really badly, backfiring, smoking and not firing on all four cylinders. Further investigation revealed poor compression, the decision was then taken to look at the top end which revealed more problems. Sealant has been used on the cam cover which has broken down and found its way into the engine. Valve shims are within tolerance meaning that’s not part of the problem but the there are plenty of signs of scoring on both. Theres plenty of oil at the top but there was also a hint of of a metal shimmer, not good. The oil was then dropped and the filter removed, there’s a layer of sludge contaminated with metal flecks… Unfortunately a full strip and rebuild is required before going any further.