Moly 60 on the head bolts? First time I've ever heard of that. Some manuals call for clean dry threads, some don't say. But any lubricant you put on the threads will allow the bolt to turn significantly farther before the proper torque is reached than no lubricant, so you might be risking stripping the threads or breaking the bolts.
I have done a LOT of work on my cooling system lately, it was overheating badly. Never got a chance to actually ride it before it overheated, it seriously overheated while warming up the engine. I drained and refilled it many times. I removed the disc, spring, and plunger from the thermostat, so I knew that was not failing to open. While I had it apart, I checked that the pump impeller was turning, and installed new oem 0-rings on the thermostat and water pump covers. I removed the radiator, and poured water through it several times. It went right through. No indication of the radiator being plugged. The system had NO external leaks. There was no water in the oil, or oil in the water. A compression test showed good compression all the way around, not likely with bad head gaskets. I was going to do a leak down test on it, but the problem fixed itself first. I have over 300 miles on it since it last overheated.
I personally believe I had a large air pocket trapped in the system somewhere, that would not come out the normal way. I would fill the system including the reservoir, let it overheat, and quickly shut it off. The next day the reservoir would be down slightly. I removed the hose from the reservoir to the radiator to prevent backflow (because the reservoir is higher than the radiator) and removed the radiator cap. It was full. I still thought there was air in it. I removed the drain plug and drained it, then filled it from the drain with a pressurized garden sprayer, from the bottom up. I kept pumping water into it for some time after it was running out the radiator opening, then put the drain plug back in quickly. So far so good.
Remember that coolant expands when hot and contracts when cold. So as the engine warms up, it is normal for some coolant to be pushed out through the radiator cap and into the reservoir. When the engine cools down, it creates a vacuum in the system, which creates a suction at the radiator cap, and PULLS it oven, sucking the coolant that came out earlier back into the radiator/engine from the reservoir. If the reservoir is empty, it will suck in air. Not good. If the radiator cap will not open under vacuum, it will collapse the weakest part of the system, usually the hoses, but also the radiator core itself. Definitely not good. If there is a leak in the system somewhere, either internal or external, it may suck in air from the leak rather than through the radiator cap.
Since your cap is new, it is probably good. You can also pressure test the system. The problem with that, as well as doing a compression and leak down test on the cylinders, is that the leak may not show up until the engine is hot.
With a full radiator to start with, and a full reservoir, and after running the engine for awhile, then letting it cool off completely, is the radiator full when you remove the cap (with the hose to the reservoir disconnected)? If the system is not sucking coolant back in, that means either there is no vacuum in it, which could be caused by a leak (or IMO, an air pocket) or a bad radiator cap. Those are about the only possible causes. Also IMO, an air pocket can cause the water pump to cavitate, meaning it is not circulating coolant. An air pocket SHOULD work it's way out with a few heat/cool cycles, but I'm not entirely sure that is the case with the Goldwing, or mine anyway.
When the engine smoked on startup, was the bike in the sidestand or centerstand? if it was on the sidestand some smoke is normal. But not a whole lot. About the "smoke rings" did it do this only once, or has it done it several times?
A leaking head gasket will almost always result in coolant in the oil or oil in the coolant, or both. It will also result in a loss of compression, resulting in rough running. If it is external, it will make a noise.
I have done a LOT of work on my cooling system lately, it was overheating badly. Never got a chance to actually ride it before it overheated, it seriously overheated while warming up the engine. I drained and refilled it many times. I removed the disc, spring, and plunger from the thermostat, so I knew that was not failing to open. While I had it apart, I checked that the pump impeller was turning, and installed new oem 0-rings on the thermostat and water pump covers. I removed the radiator, and poured water through it several times. It went right through. No indication of the radiator being plugged. The system had NO external leaks. There was no water in the oil, or oil in the water. A compression test showed good compression all the way around, not likely with bad head gaskets. I was going to do a leak down test on it, but the problem fixed itself first. I have over 300 miles on it since it last overheated.
I personally believe I had a large air pocket trapped in the system somewhere, that would not come out the normal way. I would fill the system including the reservoir, let it overheat, and quickly shut it off. The next day the reservoir would be down slightly. I removed the hose from the reservoir to the radiator to prevent backflow (because the reservoir is higher than the radiator) and removed the radiator cap. It was full. I still thought there was air in it. I removed the drain plug and drained it, then filled it from the drain with a pressurized garden sprayer, from the bottom up. I kept pumping water into it for some time after it was running out the radiator opening, then put the drain plug back in quickly. So far so good.
Remember that coolant expands when hot and contracts when cold. So as the engine warms up, it is normal for some coolant to be pushed out through the radiator cap and into the reservoir. When the engine cools down, it creates a vacuum in the system, which creates a suction at the radiator cap, and PULLS it oven, sucking the coolant that came out earlier back into the radiator/engine from the reservoir. If the reservoir is empty, it will suck in air. Not good. If the radiator cap will not open under vacuum, it will collapse the weakest part of the system, usually the hoses, but also the radiator core itself. Definitely not good. If there is a leak in the system somewhere, either internal or external, it may suck in air from the leak rather than through the radiator cap.
Since your cap is new, it is probably good. You can also pressure test the system. The problem with that, as well as doing a compression and leak down test on the cylinders, is that the leak may not show up until the engine is hot.
With a full radiator to start with, and a full reservoir, and after running the engine for awhile, then letting it cool off completely, is the radiator full when you remove the cap (with the hose to the reservoir disconnected)? If the system is not sucking coolant back in, that means either there is no vacuum in it, which could be caused by a leak (or IMO, an air pocket) or a bad radiator cap. Those are about the only possible causes. Also IMO, an air pocket can cause the water pump to cavitate, meaning it is not circulating coolant. An air pocket SHOULD work it's way out with a few heat/cool cycles, but I'm not entirely sure that is the case with the Goldwing, or mine anyway.
When the engine smoked on startup, was the bike in the sidestand or centerstand? if it was on the sidestand some smoke is normal. But not a whole lot. About the "smoke rings" did it do this only once, or has it done it several times?
A leaking head gasket will almost always result in coolant in the oil or oil in the coolant, or both. It will also result in a loss of compression, resulting in rough running. If it is external, it will make a noise.
