Thanks umberto for the manual. I found the info on Page 206. I think that the top end is off an 88 and the engine no. seems to indicate it's an 87. Either way the workshop manual will be extremely useful. Alexander-vmann, thanks too for your answer - spot on - it should be 0.6 to 0.7mm. The gap in the new plug does look large. I've never had a bike that lacks compression on this scale. Going by what I've read it should take an awful mighty kick just to get it turned over. It could be ring wear, or damage to the cylinder wall. I've had her running and she doesn't run badly - jetting (bugger it) will be my next hurdle, but that's another topic altogether.
Have those of you with lack of compression had starting issues?
The carb is a Mikuni round slide and I measured it at 38mm. The float is working okay, opening and closing the needle valve, so as far as starting is concerned the only thing of importance should be the pilot jet and the idle screw. I'm at nearly 2,000 metres/6,500 feet and the humidity, though not recently because it's winter, is often at 100 %. Time to start a new thread? Oh, by the way, I was an auto engineer (posh word for a mechanic) in my youth, so I'm not under any illusions: starting could be down to a whole host of things besides the carburettor.
