Racking my brains I think I know the moment when it went, I had ridden it hard for about 10 minutes between 60 and 70mph along a dual carriageway. I have one of Darryl's hand chokes and did several checks to make sure the mixture was fine. Stopped for a couple of hours and then rode back at about the same speed but after a minute or so it seemed to loose power so I pulled the hand choke and it didn't make any difference until I got the speed down to less than 50mph. Since then it has refused to tickover and been even more boggy than normal in the mid range hence my visit to Sash's dydno.
Anyone like to hazard a guess as to the cause? the plating is completely gone on the exhaust side bellow the port and that side of the piston is completely mashed with deep gouges, obvious metal to metal contact. There are also some patches above the inlet near the top of the barrel where the Nicacil appears to be missing. The rings, bearings and seals were replaced less than 2k miles ago and I have always run it on 3% (Groundsman for the last 2k).
I'm off on a mini tour of Europe next Friday so I'll have to borrow the TS1 engine in my other scoot which'll mean cutting the battery tray
with bits of the liner missing much like yours. I've retired it for the time being.