Hi all, thought I'd start a thread to share the 'fun' I will soon be embarking on! In summary, the bike had been running fine... Then in recent months it became really unwilling to start. Then after a few weeks of getting to the point of almost not starting at all, on the last couple of outings the bike would run like **** after it had warmed up - pretty much unusable. Carb Clean I dived into the carbs, turns out there was a blocked pilot jet on the left carb of the pair. I managed to predict this after noticing that exhaust manifold pipes 1 & 2 didn't get warm on initial startup! Having cleaned out the carbs, things seemed promising. Still not instant starting, but much better than before and I thought any residual difficulty would be cured by fine tuning of the fuel screws, idle speed, etc. However, on the most recent ride, once things had warmed up, the rough running returned. I started reading around this most helpful forum and this brought to light the need for regular valve adjustment and the potential for low compression. And with the bike virtually unrideable, what did I have to lose?! Compression Testing So in goes the compression tester, which provided the following warm readings: cyl - psi 1 - 130 2 - 130 3 - 140 4 - 140 Not looking good! After adding a teaspoon of oil (on a different day, so engine was cold): cyl - psi 1 - 270 2 - 250 3 - 280 4 - 240 Quite an improvement! Measured again when cold 18 hours after adding the oil: cyl - psi 1 - 190 2 - 180 3 - 180 4 - 190 So, I'm assuming it's worn rings which are affecting compression and making it still hard to start and run poorly. But I don't see how that would make the warm running take a nosedive, after previously being fairly consistent. Valve Clearances So I proceeded to measure the valve clearances, with pretty much everything either around or below the lower acceptable range. The bike has done around 30,000 km's and based on the struggle I had getting the valve cover off, I doubt it's had much maintenance over the years. I guess this is why some people stay away from older bikes! Next Steps Anyway, as of this weekend the engine has now been removed. I plan to take it a local garage for a leakdown test (as I don't have proper system and I couldn't be bothered messing around trying to make a tyre air compressor fit one of the cheap leak down tools by bodging the appropriate air fitting). I'm assuming this will confirm the worn rings and potentially highlight additional issues with the valves, etc. Therefore I can imagine it will be a case of new rings, hone cylinders, replace a number of shims, etc. etc! I suppose only after cracking the thing open, having a closer look and taking some more measurements, will I know for sure. Would be happy to receive any advice from others who've been here before and what things to do, or avoid doing, whilst going through this process! I'll update this thread as things progress.