It's the water pump, right?

[GW Hobo]

Dont worry about overloading the water pump. It is a centrifugal pump and they are happy to run with variable flow or with no flow at all. In the process world it is common to start up a centrifugal pump with a dead head provided by closing a valve on the outlet line. The motor driving the pump will draw little more current than if the pump was running dry. Opening the valve on the outlet line and allowing water to flow actually loads up the pump and motor

Thanks Liam - good info to know when I was working through this I wasn't going to damage the pump.

[GW Hobo]

Thanks JCU, that's helpful. I'll try to test the fan as glriker suggested. (I think my days of letting it idle to kick the fan are are done, since I suspect I might do some damage if I let it get too high on temp and the fan never kicks on because the water pump is broken.)

Bottom line, seems like the only way to see whether the water pump is working (since I have no leaking anywhere) is to empty the cooling system, remove the radiator and open up the crossover tubes at the thermostat and see if there's coolant left in there.

You don't need to do that. take the rad cap off and look at the coolant. If the thermostat opens and the water pump is working you will see the coolant circulating thru the rad.
I would be extremely surprised if your water pump isn't working if it isn't weeping thru the hole in the bottom or you haven't heard any unusual noises like the bearing seizing up..
Also the 1100 only holds 3 liters of coolant in the system and even if you drain the rad there will be coolant in the coolant passages in the engine

Thank you 5speed, appreciated this info on my journey.

[GW Hobo]

I wanted to circle back with this august group for both the technical information, thoughts, and considerations as I tackled this issue. From the diagram on coolant flow to the amount of coolant in the rad (not sure why I thought it was higher than it was) to the bullet-proof nature of these water pumps, I used it all while testing the fan, switches, etc.

I finally grabbed the Clymers and retested the thermostat. It opened, but not wide enough as my bride walked up to the stove and asked me what I was cooking. I had a spare that I tested, and it was much better. It also had the little metal-dingy metal thingy hanging out the hole in the thermostat, and this evidently is not stock - so I removed it too. (Didn't make the bike go faster). Not sure what this would prevent the fan from going on, but to @JoeCoolsUncle's point, maybe I just didn't wait long enough, especially if the thermostat wasn't opening wide enough.

I put the radiator back together (for maybe the 5th time), filled it up and started the bike. She proceeded to kick on the fan after a good long time, and everything was awesome, but now I had a leak by the water pump housing. I know the water pump was not the issue because I'd just replaced the gasket on this when i again checked it for any issue/movement in the blades. Unfortunately, I over tightened the crush washer I'd been over-using and, thinking it needed one more turn, put a hairline crack in the housing. I'd had it powder coated back in the day too. Got one off ebay and, one new housing pump later and some new crushwashers, the radiator was running like a champ.

I've been running it a number of times since putting it back on the road and the fan kicks on (and stays on after stopping) and there's no other leaks or warning lights, so I think I've put this issue a-stern.

I think this bike will be forever testing me. The cooling system was not something I'd been through before - now I have. And thanks to you all, she's back on the road.

[Fred Camper]

Good to hear this update. Nice to have better cooling finally.

[Shadowjack]

That little metal-dingy metal thingy in the thermostat is present in the aftermarket thermostat I just bought for my old car. I'm assuming it allows any air to pass through when filling the system, but essentially closes under water pressure, allowing quickest warmup.

[Fred Camper]

That is true Shadow jack. Let's air leave the system and allows it to pull in coolant but does not waste heat when te Stat is closed.