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Coolant Changes

Changing the Coolant
Filling the Radiator

Mon Jan 29 1996 Harold Gantz ( Asked:

I plan to replace the coolant. Is there any easier way that requires fewer fuel tank removals?

From: “Diaz Jon” <>

Yes, drain the system down at the water pump (don’t forget the new crush washer) and pull the gas tank back so you can remove the radiator cap. Do not lose the rubber gasket inside the radiator cap….funny/embarrassing story I’ll review another day. Let the system drain for 15-30 minutes, then replace the drain plug, and slowly (trickle) the new coolant into the system, stopping every few minutes to let things settle. You should be able to get most of it in there that way.

Remove the coolant overflow (since you are servicing the battery, you’ve already removed the bracket holding everything down) bottle and dump the old stuff into your bucket. I fill the bottle to the halfway point between MAX and MIN, and then after that first ride, top the overflow back up to MIN after everything cools off.

Some folks go to the MAX level, and end up having coolant pee all over them when the bike gets stinky hot (right Joe Senner?), but I’ve used the MIN level as my cold setting and never had a problem.

Date: Mon, 21 Aug 95 17:00:52 EDT
From: Tom Coradeschi <tcora>

Jonathan Hutchins wrote:
When you’re refilling the radiator on the K bike (K100), what’s your procedure?

Pull the tank back and to the left as far as it will go. Use a rag (school of hard knocks, here) to protect the tank from the plastic (still hard enough to scratch the paint) bracket on on the inside of the RS fairing.

Fill the radiator and start the engine. When the thermostat opens, the coolant level will drop, so top it off again, put the cap on and put the tank back where it belongs.

Check the overflow to make sure it’s up to the “Max” line and go for a ride. Next morning, check the overflow again. It will have dropped a little, but not much, so bring it back to Max and you’re done.

Coolant Change Trick

By Fred Scott
September 2000

This may well be an old trick, but I noticed that your coolant articles didn’t mention it, so I thought I’d pass it along. It’s a simple method for changing your coolant without ever removing the gas tank.

What you need is a fluid pump with an attached hose. You can buy these at auto parts stores for less than ten dollars, and they’re designed to screw onto the mouth of standard antifreeze containers.

Unscrew the top mounting screw on your radiator so that it can swing forward about an inch. The filler cap is connected to the radiator by a short rubber hose. You can now disconnect this hose from the radiator without removing the fuel tank. So once you’ve mixed up your antifreeze, refill the original container with your mixture, and put the pump on the container. Use the hose on the pump to pump the fluid directly into the radiator. Pump slowly so that the fluid doesn’t spill. Eventually, the radiator will be almost full, and you can reconnect the hose. Fill the reserve tank as normal.

You will have some air in your cooling system, so don’t go on a long road trip right away. Take some short rides, and let the engine cool between rides. Each time it cools, fluid is sucked from the reserve tank into the system, and when it heats again, air is released from the overflow into the reserve tank, and out. So carry a small amount of coolant with you to top off your reserve. In my experience, half the capacity of the reserve tank is plenty.

I don’t know if this is actually faster than taking off the tank. If you’re a pro, it’s undoubtedly slower. However, it’s also a lot easier.

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