I just thought of summat fellers. I had to get a new plug for the carb manifold take off as it had a dodgy one. the other three looked ok but slipped back on very easily (no pliars to open clips just pushed straight back on)with the clip in situ. im wonder if disturbing them has made them leaky. if so perhaps they leak when its very cold (three degrees yesterday here and just as cold for my run in today) but as the engine heat gets to them tthey flex and expand a tiny bit and seal, hence the problem dissaears. This problem has only manifested since 1) I balanced the carbs 2) I removed and refitted the manifold plugs 3) it got really bloody cold.
So, i'll order new plugs/clips off fowlers today (should have changed them all the first time, just ordering the one the postage was as much as the parts!) if that doesn't sort t carbs off again this weekend, at least ive got that down to an easy job now, and with a big heater in the workshop im enjoying being out there with me dawg and raddyo..and cheers mike, first thing i'll check again is the float heights..