K100 turbo in the workshop.

[Ijustwanttoseethephotos]

After 7700km of (ab)use, the K100 turbo has developed a problem! Number 3 cylinder spark plug is a bit oily.
The valve clearances are OK, the other spark plugs are correctly coloured.
Fuel consumption hasn't changed but the oil level does drop slowly whereas before it never moved between 2000km
changes.
I suspect number 3 piston has suffered some damage, either a ring land has collapsed or this cylinder is the one
most prone to detonation, which has damaged it.
Tomorrow I'll finish removing the cylinder head to check the valves, then I'll remove the piston for inspection.
There is a possibility that the Nicasil plating has lifted, not an uncommon problem, so it may mean the engine is
beyond economic repair, all is not lost as K1100 engines are quite cheap!
I don't know whether BMW will honour a warranty claim with this problem as it has been regularly serviced!

 

[dr nosh]

What. That's only 4784.5 miles. I'd go for a warranty claim.

 

[Ijustwanttoseethephotos]

Today I removed the cylinder head and withdrew the pistons and found that the cylinder with the oily plug had a broken top, (compression), ring.
They're standard BMW rings and are cast iron.
They is no evidence of detonation, all the internals are in perfect condition, fortunately the bore is unmarked.
I've spent most of this afternoon on the phone trying to source a steel/chrome compression ring, the bore size of 67mm is not a problem but the bike uses a bizarre 1.1mm width piston ring rather than the norm of 1.0mm. (Japanese 600cc), without success.