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 Post subject: Cooling problems (overflow)
PostPosted: Sun Mar 04, 2018 2:27 pm 
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Joined: Sun Mar 05, 2017 6:09 am
Posts: 72
I drove my RD 500 with low RPM till 7000 at 4°C and the temperature was still 74-78 °C. :???:
After I drove her them with 10 000rpm the temperature went not down, only the coolant fluid run out.
Looks like too much pressure inside the system.
No thermostat assembled.
Assembled is GP radiator. They say 10-15% more cooling power.

I changed the coolant filling part and assembled one from Aprilia. Also 0.9 bar. Refilled the radiator.
Same problem.
I removed the water pipe at the water pump and radiator. Only 600ml water came out.
Does anybody knows something like this?
In the manual is written from 1.95 litre, but I was only able to fill in 1,5litre.
Is in wrong written in the manual, or something wrong with my RD? :-?
Or is based on the situation, that the lower cylinders are still filled with water?


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 Post subject: Re: Cooling problems (overflow)
PostPosted: Sun Mar 04, 2018 2:32 pm 
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Joined: Fri Jul 28, 2017 4:23 pm
Posts: 46
Location: Stratford Upon Avon UK
3XV wrote:
I drove my RD 500 with low RPM till 7000 at 4°C and the temperature was still 74-78 °C. :???:
After I drove her them with 10 000rpm the temperature went not down, only the coolant fluid run out.
Looks like too much pressure inside the system.
No thermostat assembled.
Assembled is GP radiator. They say 10-15% more cooling power.

I changed the coolant filling part and assembled one from Aprilia. Also 0.9 bar. Refilled the radiator.
Same problem.
I removed the water pipe at the water pump and radiator. Only 600ml water came out.
Does anybody knows something like this?
In the manual is written from 1.95 litre, but I was only able to fill in 1,5litre.
Is in wrong written in the manual, or something wrong with my RD? :-?
Or is based on the situation, that the lower cylinders are still filled with water?
Could be your water pump seal has gone. Check for coolant in the gearbox oil.

Sent from my HTC Desire 530 using Tapatalk

_________________
Current Bikes
1984 47X RD500LC, 2007 GSXR750, 1987 VF500F2F
Past Bikes Include
RD250LC, RD350YPVS LC2 Race Bike, RD350F2, 1976 CB400F


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 Post subject: Re: Cooling problems (overflow)
PostPosted: Sun Mar 04, 2018 3:39 pm 
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Joined: Sun Mar 05, 2017 6:09 am
Posts: 72
Hm,
sound at the first view not so logic. :smt017

If the sealing ring is defect, the pressure in the cooling system should be less.

But the water is flowing out at high rpm from the drain hose of the reservoir.
The smaller reservoir what I use gets over flooded after 500m at 10 000 rpm.

I think more about a defect cylinder head sealing. :-(
But I don´t like to disassemble the cylinder head, if it is not needed.


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 Post subject: Re: Cooling problems (overflow)
PostPosted: Sun Mar 04, 2018 3:47 pm 
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Joined: Fri Jul 28, 2017 4:23 pm
Posts: 46
Location: Stratford Upon Avon UK
3XV wrote:
Hm,
sound at the first view not so logic. :smt017

If the sealing ring is defect, the pressure in the cooling system should be less.

But the water is flowing out at high rpm from the drain hose of the reservoir.
The smaller reservoir what I use gets over flooded after 500m at 10 000 rpm.

I think more about a defect cylinder head sealing. :-(
But I don´t like to disassemble the cylinder head, if it is not needed.
Yes. With that extra information, it does sound like a head gasket has blown.

Sent from my HTC Desire 530 using Tapatalk

_________________
Current Bikes
1984 47X RD500LC, 2007 GSXR750, 1987 VF500F2F
Past Bikes Include
RD250LC, RD350YPVS LC2 Race Bike, RD350F2, 1976 CB400F


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 Post subject: Re: Cooling problems (overflow)
PostPosted: Sun Mar 04, 2018 4:53 pm 
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Joined: Sun Oct 28, 2012 6:38 pm
Posts: 773
Location: Spielberg, Austria
You can make a pressure test of the cooling system.

Apply some pressure to the system and wait - if the pressure drops you have a leak.
Check after the test if the crankcase is full of water (head gasket)

_________________
My bikes:
RD500 YPVS 1GE
RD350 YPVS 31K 1985
Honda NS400R NC19
Honda CBR 1000 RR SC57
Yamaha R1 RN04


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 Post subject: Re: Cooling problems (overflow)
PostPosted: Mon Mar 05, 2018 12:38 pm 
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Joined: Sun Mar 05, 2017 6:09 am
Posts: 72
Thanks for the info,
but I do not have this tool.
And I´m also not a fan in filling my cylinder with water. :smt009

A manometer instead the radiator cap would be better to see, if overpressure will get produced.
I also do not have such a manometer.

So I need to remove the cylinder head. :cry:

But I´m still searching for somebody, who could give me the information about the water amount.


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 Post subject: Re: Cooling problems (overflow)
PostPosted: Tue Mar 06, 2018 2:58 pm 
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Joined: Sun Mar 05, 2017 6:09 am
Posts: 72
The cylinder head gasket is gone at the upper left cylinder. :roll:

Lucky me, no water in the cylinder. :grin:


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 Post subject: Re: Cooling problems (overflow)
PostPosted: Tue Mar 06, 2018 3:55 pm 
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Joined: Thu Mar 09, 2006 12:54 pm
Posts: 237
Location: Germany
That looks like a crappy aftermarket gasket set.
The OEM Yamaha head gasket is black and expensive but it works.

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Martin


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