Over heating issue

[Mehrdad]

Hi everybody,
Let me tell you the story first,
It was a few months ago that I had to replace the coolant joints on the cylinder head since the they had a leak .These things were really corroded and I had to break them into pieces and they them out .Finally I got Oem orings and joints, applied a bit of silicone grease on them and got them installed, I also replace the valve cover gasket with original.
The bike started the nicely and worked perfectly until last weekend. It was OK first but started to heat and temp guage was close to red line .I switched the bike off and let it cool down.
After starting again it heat up and I noticed the engine is going off it self again if I don't turn the throttle. I did few check found these thing,
1- there is very small leack on the bottom of the radiator.
2- Since I was planning to flush the cooling system again I used distilled water in the cooling system and the water level was OK in the reservoir but it was low in the radiator cap.Just to mention, the radiator cap is not in a good condition but I don't see any leaks around it.
3-I checked the oil in the crankcase and I'm not sure if there is water in the oil from the colour of oil.
I put water in the radiator and started it and there was no bubble in the radiator the bike worked fine but I was not sure to ride it or no. I thought it's better to check with you first.here are my questions
1.Do you think there might be problem with coolant joint orings and water leaks to crankcase?
If it's that,how to check there is water in oil?
2.Do you think radiator cap or that small leak can cause overheating to make the bike go off when it's getting hot ?
I have attached some pictures.
I didn't feel any oil on my finger when I touched the water.

Thanks in advance for any help,
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[MaxMidnight]

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When you say 'bike go off' do you mean cut out?
If it is cutting out is that with the choke off have you synchronised the cabs and set the tick over?
I can't thing how leaking O rings would cause it to cut out.

Easiest way to see if coolant is getting into the oil is to mark the level of coolant in the reservoir when cold and see if you are loosing any and getting emulsified oil.

If it is overheating:

1. Pressure cap - loosing pressure results in the coolant boiling at a lower temperature which can cause overheating. Caps can be tested but probably cheaper and easier in the long run to replace it.
2. Air trapped in the system - was the drain valve set to 'Open' when you re-filled the system?
3. Blocked radiator - if the link pipes were corroded then that would suggest that there hadn't been any corrosion inhibitor in the coolant - and excellent way you ensure the radiator blocks up. Feel for cold areas on the rad core as it warms up.
4. Thermostat not opening - test in boiling water for the opening point.
5. Water pump not circulating the coolant - look for flow through the system at the coolant manifold.

 

[Mehrdad]

Hi mate,
Thank for your help,
What I meant by going off is that it's rpm is slowly going down until it stops.
Also as I have mentioned, there is a very small leak on the radiator so I guess I'll have to fix that too.
I'll do all these check ups and get back here,
Really appreciate it!

 

[02GF74]

The coolant should be a mixture of water (distilled or deionised is good) and anti freeze., see manual for composition %

There is a plastic valve at the bottom of the engine that needs to turned when emptying the coolant - see the manual.

Is the fan coming on?

Do have a decorative grille, usually stainless steel, fitted to the radiator - these restrict air flow.

Undo the engine drain plug and drop 1/2 cup film of oil. Water is denser than oil so it will come out first. If water has mixed with the oil, the oil will not be clear and a light coffee colour.

 

[Mehrdad]

The coolant should be a mixture of water (distilled or deionised is good) and anti freeze., see manual for composition %

There is a plastic valve at the bottom of the engine that needs to turned when emptying the coolant - see the manual.

Is the fan coming on?

Do have a decorative grille, usually stainless steel, fitted to the radiator - these restrict air flow.

Undo the engine drain plug and drop 1/2 cup film of oil. Water is denser than oil so it will come out first. If water has mixed with the oil, the oil will not be clear and a light coffee colour.

I did the procedure as per the manual and I'm sure that I didn't miss anything.
The fan didn't come on but when I move the bike to left and right it worked mainly because, the water level wasn't up the fan sensor but not sure,
I'll drain the oil to see if there is any water coming out first.As I have mentioned I used distilled water instead of coolant as I was planning to flush the cooling system.
Thanks for your help

 

[MaxMidnight]

While we tend to call the coolant 'anti-freeze' for the majority of us the most important component is the corrosion inhibitor.
Another reason we add 'anti-freeze' is that its boiling point is higher than that of water.
Adding pressure in the system raises it further.

So, if you are running on pure water with a dodgy pressure cap then you have reduced the boiling point of the coolant significantly which will result in overheating at a lower coolant temperature.

I would fix the leak (which may lower the pressure within the system, replace the pressure cap and re-fill with the recommended 50/ 50 mix and then re-assess the situation.

 

[Mehrdad]

While we tend to call the coolant 'anti-freeze' for the majority of us the most important component is the corrosion inhibitor.
Another reason we add 'anti-freeze' is that its boiling point is higher than that of water.
Adding pressure in the system raises it further.

So, if you are running on pure water with a dodgy pressure cap then you have reduced the boiling point of the coolant significantly which will result in overheating at a lower coolant temperature.

I would fix the leak (which may lower the pressure within the system, replace the pressure cap and re-fill with the recommended 50/ 50 mix and then re-assess the situation.

I'll do it for sure.I live in Dubai and it's extremely hot here . Riding a bike is nearly impossible during the summer .
I'm going to use Engine ice coolant this time .it's quite expensive here but I think it's worth it.
Thanks for your useful information