Have you checked out that Rare Earth Magnet topic were the ignition does not work well due to the magnet on the rotor going weak from age and being overwhelmed by the rotor's electromagnet field? If this is the issue then the bike should run nicely if you temporarily disconnect the rectifier/regulator unit. Apologies if this has already been done.
Blue Hylomar: I am not sure if anyone has mentioned how if this sealant is used in excess and gets squeezed into the engine oil it forms slimy bits that can block filters and fine filter mesh. It is then very hard to wash out of the fine mesh on the oil pump intake mesh.
Hi Paul, not too sure of you mean the magnets on the Boyer Bransden rotor/static plate? I have started to look at some of the threads that come up in a search on rare earth magnets - some relate to bikes with Yamaha pointless ignition but looking for possible implications if Boyer magnets have lost their field strength.
I'm not too worried about getting Hylomar inside the engine - only put a smear which will not even squeeze out when the joint is tightened up. And I was careful when I washed off the compound I put there the other day.
Re. not running, my Willing Assistant came into the garage to help with the strobe. She said that the bike sounded rough and she thought r/h cylinder not firing as well as l/h. Certainly, as I tried to rev and the bike just died, it sounded rough and felt as if maybe one cylinder dropped out.
There's a new ignition coil, HT leads and spark plugs. So if we assume they are all ok (I know, I already said assumption is the god parent of all foul ups) then I suppose that suggests carbs. Maybe a blockage on the r/h carb would lead to the symptoms?
I took carbs off, stripped and washed when I first had the bike and found the fuel tank was full of rust. But might be something to look at tomorrow. Pull the carbs off and wash them out again. Make sure carb cleaner can be sprayed right through the pilot system - sure I read that here somewhere?
Damn! Referring back to Paul's suggestion - I just realised, was having a problem with the strobe. Couple of times it lost it's flashing light when I revved to check the spark advance. I thought it was the strobe - but maybe the Boyer system is giving up when revved? DEFINITELY one to think about. Research . . .