since i got and recommissioned the 1991 project bike it's been hard to start. during the rebuild i lapped the valves and the rings and pistons were visually good but i didn't have a before tear down compression figure. I got highest figure of 110psi having warmed the bike, with decomp cable disconnected and the throttle open. I poured some oil down the pot to see if the figure lifted but no change, in fact it fell away to 90 psi, i think as the bike cooled as it took me a few mins to find a way to get the oil down the pit when you can barely see the hole. I'll pull the head off, anything in particular i should be looking for ? Should I pour some petrol in it while inverted and see if it leaks ?