Thanks guys,
Yes that make a lot of sense, the head gasket is designed to hold combustion pressure in, not cooling system pressure out, so I will gradually increase the pressure as you suggest.
I haven't added here that after I had the same problem with the head BigK sent me, the welded one, I figured that eliminated the head as the problem, so when I had Greg Ball bore my cylinder and skim the top of it, I also had him skim the original head and put the original fittings back in it for me, so I am now using the original.
Yes Monty, I have a good collection now of blown head gaskets and others that were ruined each time I have had to pull the bloody thing apart, well over 10 times this season
. I will never need any more of the other gaskets though as I have had to buy sets each time
One other variable which has occurred to me recently. The bike was in such bad shape when I got it, I decided to replace the hoses just so I knew they were OK. I did not buy a set made for the bike, at the time I couldn't find one and I have not since found one. I went to the local Pirtek shop and bought standard radiator hose. One of the reasons I want to run the clear hose test is to make sure that none of the hoses going around bends have closed off the flow.
And yes, it has crossed my mind I'd like to give Mr Hardo a bit of a hurry up
I'll keep you posted.