Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
The brake light switch attaches to a bracket, on the 500 and I'm fairly sure the 550F it's a bracket welded to the frame, on the 550K however it went into a bracket which was separate and attached to the upper rear engine bolt, probably why it's loose as on the 500 and 550F you wouldn't really need to remove it. It's missing a long thin spring which goes through the hole in the pin you can see protruding from the switch.If the carbs are missing I'd fit the carbs off either the 500 or the 550F as the 550K carbs were much different and TBH are pretty pants in comparison. You'd also need the airbox to match but it's a worthwhile change as the 550K carbs really are that bad.
That seems pretty good to me. I was in semi shock having got a quote at the weekend for £250-300 to vapour blast full motor. Thought it was extracting the michael at that!
Make sure you also renew the primary shaft dampers along with the primary chain, it will last a lot longer if you do and will also be far quieter as they tend to go hard and lose their damping ability as a result.