Had another go today, stripped it all down and ready to put the new chains on. The woodruff key on the crankshaft was fooked, no idea how but the sprocket wouldn't come off so I had to grind enough of the key off to remove it.
I knew the chain rattled before, but when I checked it the tension seemed fine and there was oil on it. Took a look at the oil nozzle and this is what I found (sorry for the bad quality):
I'm guessing it was the old version, completely gummed up with crap and I couldn't get it clear even after scraping away at it! The small bit sticking out the back snapped off when I tried removing it but thankfully it came out with some gentle persuasion.
The balance chain was slacker than George Michael's hoop and that was on the tensioner side as well, plus one of the guide rails was in two pieces. I started to panic once I took the chain off because the balance shaft sprockets were filthy and I couldn't make out the timing marks!
Got there in the end though, gave everything a quick clean and will put it back together again once I can get a replacement woodruff key. It's certainly been emotional, plenty of blood, sweat and tears in equal proportions as this is the first time I've attempted something like this. Hopefully it'll go back together smoother than it came apart!
