Spark plug drain holes

[His Dudeness]

Lack of time meant I only got back to this yesterday and only for a couple of hours.
I’d ordered a 10mm x 1mm tap which extracted an astonishing amount of grit from the plug hole. That explains why it needed so much torque to get the plug out… I was surprised it didn’t shear off.
With the plug hole blocked off to stop debris dropping in it was then possible to clear the drain hole between the two plug wells. No way would an air line have done the job, the passage was stuffed with tight packed oily grit and needed a long drill bit to dig it all out.
Still have to persuade plug 2 to come out in one piece then I can clean out that thread... and then there's the right hand half of the engine, which is likely to be worse.

The right side will most likely be worse. The bike leans to the left on the side stand so the left side of the engine points down and has a chance to drain whereas the right side points up so all the rain water and dirt collects on that side around the spark plugs. Take your time when you're undoing those plugs and clean the area as best you can. Sometimes working the plugs in and out with a bit of oil helps to clear the threads