[Windjammer, I wouldn't assume radiator is dirty.Just clean cap.Red light may be on because of leak, you became low on coolant.
quote author=Windjammer link=topic=9062.msg71256#msg71256 date=1254509941]
Coolant leaking from the cap would indicate that the return line to the coolant reservoir is clogged. The cap could still be functioning properly holding pressure at the correct level.
The cap is a two function sealing unit, one to seal the radiator with pressure and the other to seal the cap to make a closed system which includes the reservoir.
Overheating is another issue that may or may not be related to the leaking cap.
I'd suggest looking to insure the radiator is completely filled to the top and the reservoir is at the correct level.
There can be many reasons for overheating the motor. Just to mention a few: Too advanced ignition timing, malfunctioning water pump, blocked air flow to the radiator.
If the fan comes on and cycles on and off I would say there is no problem with your cooling system and you have no overheating problem. You do not indicate how you have determined there is a problem.
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While riding, Water started spewing up on the right side (At the cap) and got my attention. 2 weeks prior to this the bike was running hot with the red light coming on. I removed the cap and poured in a quart of antifreeze (Honda) That filled it up and I thought was the end of it? Nothing leaking from under the bike or dripping from the bottom hose. Usually makes me think of the waterpump or hoses. Season is just about finished here in Chicago area and my last planned ride is next weekend for a get away. Looks like more added to list of winter projects on the Lady. Front fork seals, remove fairing to replace most bulbs, New Air Filter, Remove rear wheel and grease splines, Change final drive gear oil, Still have original plugs in. Change that and new vent tubes. Should do the Desmog? Maybe. Check bearings to while I have the rear wheel off. Just a to do list as of now. Oh and check coolant system. (Clean Radiator now)

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