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Discussion Starter #1 (Edited)
So, I'm about to renew my coolant.

My Haynes manual says to fill the system to the base of the filler neck, run the engine for a while until the thermostat turns on the water pump and expels some air from the system, then top up, and repeat, probably several times until all of the air is expelled. It specifies to do this with the cap off to allow the air to escape.

The filler cap is under the petrol tank. Does this mean I have to refit the tank every time, then remove it to top up? I'm planning to do 3 flushes before the refill, so this will take all day long, if not longer.

Is there a work around?

Another thing, I'm planning to use a flushing agent - should I put this in the reserve/overflow container as well, or could the pipe leading to it have some left over even after flushing again with distilled water?

And one more question - is it really necessary to pre-mix the coolant or flushing agent with water before filling? Can't the mixing be done in the engine as the stuff circulates?
 

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The coolant and water will mix together just fine inside the system. Maybe most folks pre-mix to get the ratio just right.
Flushing 3 times does seem like quite a chore. Anyway, you should be able to access the filler cap by pulling the tank's retaining clips, then lifting the tank up and to the left just enough to expose that cap. I don't need to undo any fuel lines or electric connecters to do this. Drain, fill, set the tank on center so you know the fuel lines aren't kinked, and start it up. My OM suggests running the engine "briefly" , kneading the hoses to purge any air that didn't escape, and topping up the main fill. Close cap, run until hot, then top up as necessary in the expansion tank. Frankly, I fill the expansion tank up to the "min" mark when I fill the system the first time. Works like a charm for me. Also I pre-measure the amount of coolant/water I'm putting in, when the main fill is full, what's left is usually just about enough to bring the overflow up to "min".
Don't know about the flushing agent.
Steve
1990 K75RT
 

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p.s. Since we both have RT's, I should mention that I do have to take a good bit of the left side of the fairing off in order to move the tank enough to expose that filler cap.
Steve
 

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When I did my coolant this last spring I used a nifty little device called a "Rad-Kit Plus." I use it to refill the diesel engines before I start them and have found that 95% + of the air in the system comes out with the refill.

The system I use applies vacuum to the cooling system and draws out the air in the system. After the vacuum has been drawn and held for a short time the pre-mix of coolant I have in a bucket next to the vehicle is drawn by syphon tube into the system by the vacuum. After the vacuum is gone the "Rad-Kit" is removed from the fill neck and the cap is reinstalled. Top off the reserve tank and ride it. It didn't even touch the coolant I put in the reserve tank. It is a great system to use and some parts stores rent them.

I learned to use them on diesels due to the fact that you don't want any air a diesels cooling system or it will cavitate and erode the cylinder liners and aluminum components. Since K-bikes are aluminum I figure it would be easier on the system than steam pockets and spot heat stress.
 

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Discussion Starter #5
Thanks for the tips.

I did it pretty much as I described, and got quite quick at taking the tank on and off, so no worries really.

I did end up making a very concentrated coolant:water ratio, as there wouldn't have been enough left over for a second batch so I thought I may as well use it up. Shouldn't cause any issues should it?
 

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If that concentrated coolant to water ratio is much more than 50/50 with coolant percentage the high part, you will have problems with overheating, or at least more times when the fan runs. This results in a hot rider.
 

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Discussion Starter #8
54089093 said:
If that concentrated coolant to water ratio is much more than 50/50 with coolant percentage the high part, you will have problems with overheating, or at least more times when the fan runs. This results in a hot rider.
I'll drain some off and top it up with demineralised water.
 

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ricketyclik said:
So, I'm about to renew my coolant.


The filler cap is under the petrol tank. Does this mean I have to refit the tank every time, then remove it to top up? I'm planning to do 3 flushes before the refill, so this will take all day long, if not longer.

s?
I did mine last summer....quickly realized the problem you are up against. I never removed the gas lines just slid the tank to the left and bungy corded it in place for safety. Easy access to the filler neck with small funnel....no full tank removal....very quick and easy.
 
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