Dear diary: finally got out to fit the new exhaust gaskets and carb float valves.
Had to adjust (read attack with hacksaw) the ugly 4 into 1's at the centre stand bracket, custom fit now works very well and am pleased with result.
Would have been really pleased if second task had worked out better as I really wanted to hear the bike run with no exhaust leaks at the head......but!!!
Tore off all carb bowls, refitted new float valves and replaced cross head bowl screws with shiny new hex/allen key screws.
All set to go so turn on the gas tap and suddenly the garage is full of petrol flooding from carb number one.
Now the main reason to replace all the float valves was to stop this so am greatly displeased.
Took the No1 bowl off again but could find no fault, took apart float system and again no visual problems, rebuilt carbs, turned on gas.....more flooding!!
Anyhow, took bowls apart again and decided to check float level in petrol, darn......float sinks on one side!!!
Forum member commented that this is exactly what had happened to him when float had hole in it.
Tomorrow, wreckers.....replace float....start bike....hopefully.