I asked this question 75,000 miles ago, but no one had an answer, so I'm asking this question again at 80,000 miles. Ever since the "Triumph Upgrade" my bike refuses to maintain any coolant in the coolant recovery tank. It never overheated, nor has it ever been run too hot. But it will religiously barf out the contents when I shut it down. It won't do it while running.
I even replaced the standard under the claw tank with an external 1-liter can. It will blow the coolant out the top of the tank, then draw it empty as it cools down. That tells me there is a significant void...BUT HOW TO GET IT OUT is the question. I'm tempted to throw a cable over the rafters and hoist her up side down and shake it out of her.
I've done all the obvious and not so obvious...cracking lines, opening the bleeder at the top of the cylinder, radiator cap, coolant tank.
No harm seems to have been done so far. I thought I'd give it another go with another riding season coming up.