Spark plug drain holes

[Jules-C]

There is a hole from 3 to 4.  It doesn't take much to block the holes, an airline down the side of the plug can often clear it, or a hose blasted down there can shift it blockage.

If possible park the bike on the centre stand. I think some people have made a cover out of plastic or metal to divert water and leaves or other rubbish from disappearing down the park plug holes when the bike is parked