Hi,
I replaced my carb rubbers not long ago as they looked horrible I thought the cracks in them went most of the way/all the way through but I was wrong! Despite looking REALLY bad, there was no issue with it at all. Seems these rubbers are extremely resilient.
Once you’ve removed the rubber flappy sheet on top of the air box, you can undo all the airbox bolts & 4 jubilee clips holding it to the carbs & it slides back about 2 inches. It gives enough space to slide the carbs out enough to get into the 4 rubbers. I did this without removing anything from the carbs, just slid them one way, removed/replaced rubbers & then did the same the other side. It’s very tedious but took me, a non professional about 45 mins start to finish.
Vince.