375 views and no response, just figured nobody works on their motorcycle or it has not been a problem.
Here's what I found: The drain plug goes into a cast aluminum fitting that has 2 rubber hoses coming to it from either side of the block.
I removed the hose clamps from 1 rubber hose, took it off and the system drained, undid the other hose and it drained more coolant.
I removed the cast aluminum drain fitting to find it had a steel pipes pressed into each side that the rubber hoses connected to.
Aluminum, steel & coolant don't play well together, where the steel pipes terminated in the cast aluminum fitting there was a serious clog of corrosion.
It was so hard I had to dig it out with with a drill bit in a tap handle. Dug out the crud & soaked it in coolant flush to get it completely clean, rinsed in distilled water then cleaned up the ends of the steel pipes where the rubber hoses attached. There you have the fix.