Hi Neil. I used POR15 about 8 years ago on my TS250. I’m running higher octane fuel more recently to minimise the ethanol content, as I’m told that it’s the booze that kills most tank liners. I’ve had no problems since & there’s no hint of tackiness in the POR15 yet. Only problem was with reusing the degreaser to decoke the exhaust- the bung leaked & the contents drained into lawn. Not great for plantlife…