coolant overflow tank

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trix
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Joined: Mon Feb 25, 2008 11:44 am
Location: Northern Ireland

coolant overflow tank

#1 Post by trix » Thu Aug 10, 2017 3:06 pm

I'm using a Yamaha R6 radiator. Is there a minimum size of overflow reservoir that I would need to use and is there any issues about where its located in relation to the radiator filler neck?

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Speed Freak
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Re: coolant overflow tank

#2 Post by Speed Freak » Thu Aug 10, 2017 3:23 pm

Yes there is a minimum size - I would check how much coolant is added to the cooling circuit by the bigger cooler (I think not really much).
Then you can calculate the percentage difference and make the overflow tank the same amount bigger.

More coolant => higher amount of coolant which will be pressed out due to thermal expansion.

In reality I think the standard RD500 tank has enough reserves for the R6 radiator ;)


Tank or at least the "max" marking should be slightly below the filler neck with the simple reason that you can open the radiator cap without coolant coming out.
But basically it can be anywhere - like on the NS400R where it is above the filler neck.
There you have to drain the coolant from the tank or at least remove the bolts of the tank to get it below the filler neck, otherwise all the water from the tank will end on your garage floor when you open the radiator cap...

The connecting hose which goes from radiator to overflow tank needs to have it`s end below the "min" marking (always under water), otherwise it would suck air into the system while cooling down.
My bikes:
RD500 YPVS 1GE
RD350 YPVS 31K 1985
Honda CBR 1000 RR SC57
Yamaha R1 RN04

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