[drsureshmohan]

Over the years, riding big bikes in India and living in a hot city, I found a few effective tricks that work well to reduce engine temperature and increase comfort.

We have two types of coolant - the more popular ethylene glycol and less popular methylene glycol sold as engine ice, de-ionised water and water wetter. The properties of the glycols are anti corrosive, anti freeze and they increase the boiling point of water eg. 50:50 coolant:water - 106C from 100C and 60:40 coolant:water to 125C. Ethylene glycol is highly poisonous to our eyes. Methylene glycol is not harmful and pet friendly. The downside of coolants is heat transfer property.

De-ionised water is the safest and best, that too if used with water wetter, has the ultimate cooling efficiency which is used on racetracks and for racing due to its higher specific heat and due to the dangers of coolant spill that causes slipperiness on the track. The downside of using only de-ionised water + water wetter is that you have to change every year vs three.

The most effective coolant I’ve found in South India is de-ionised water + water wetter (max heat conductivity) next only de-ionised water. Next is water 70% and coolant 30% and the least is engine ice (pet friendly, expensive and doesn’t do well in South India's hot weather).

Please note: I’m not a sponsor for any coolant company.

Other jugaad trick is to remove the thermostat valve from the system that starts circulation of coolant straightway (I won’t risk that).

I will be glad to learn more from the group.

[Aditya]

Thread moved out from the Assembly Line. Thanks for sharing!

[CrAzY dRiVeR]

A very effective hack that I've seen some friends employ to good effect in Indian conditions is called -

Sell that Ducati, buy a Kawasaki

Jokes apart, regular checks and cleanliness of the radiator plays a good role. Most bikes will have a ton of slush thrown from the front tyres and sticking to the radiator fins. This reduced surface area for heat dissipation will really make the system work harder!

And then - there are folks who put large grills which have UK flags and such designs for the radiator guard, severely restricting airflow. A small mesh is the max you would need!

[doga]

Doesn't help that most bikes these days are fueled lean from factory to help with emission norms resulting in hotter engines. Guess best would be to get a power commander for older bikes or an ECU reflash for newer ones?

[Jeroen]

So what is the actual problem that needs solving? Do these bikes overheat?

What does the manufacturer recommend?

Jeroen

[hell boy]

Thanks for sharing your insights! Your breakdown of different coolant options and their effectiveness in South India's heat is really informative. The de-ionized water + water wetter combination definitely seems like the best choice for maximum cooling efficiency, especially given its use in racing.

I agree that removing the thermostat valve can be risky, as it plays a crucial role in regulating engine temperature. Instead, optimizing airflow and ensuring a clean radiator might be safer alternatives.

[krishnaprasadgg]

I'd like to add a few points as well.

1)Firstly regarding the coolant choices. Whenever changing between coolants, please do yourself a favor and do a thorough and proper flushing using distilled water.
No matter how many flushes you do you can never fully remove all the old coolant particles and gooey deposits from all the coolant channels but a couple of proper flushes help take out most of it, if not when you mix the new type of coolant it will invariably mix and get contaminated with the old coolant (may times they don't mix well too) and reduce the cooling efficiency from the get-go.

2) Next would be to stay on top of the coolant hose replacement timeline, rubber hoses get hard and brittle overtime, and that can cause small leaks and with the coolant system being a pressurized system, can cause sudden failures in the form of ruptured hoses, which can be catastrophic.

3) Change your coolant religiously, coolant much like any fluid breaks down after a certain number of heat cycles, the manufacturer might say to change once every 2 or 3 years, but if you live in a very demanding area weather-wise or you like to run the bike very hard or do a lot of city commutes, your coolant goes through a lot of prolonged heat and heat cycles, in that cases the given timelines don't hold good. So be mindful of that. An additional point to notice is when coolants break down(other than distilled water) they form a slimy gooey deposit and this either forms a deposit at the bottom of the radiator or at the overflow tank, which means it will travel through your coolant channels in the engine, which if gone unchecked can clog coolant pathways and is a sure shot way to have an expensive paperweight or coffee table base ideas come to fruition, so that's another reason why changing coolant religiously before it starts breaking down is a good idea.

4)This is optional but a very worthwhile step although it's expensive, ditch the rubber hoses and go for silicone hoses, multiple reasons for this, rubber hoses have an expiry and a limited number of heatcycles it can take before it starts to wear out and reduce its efficiency in flowing fluid smoothly while silicone hoses usually outlive the rider themselves.
Why do I say about coolant flowing smoothly? because it plays a big deal in how well your cooling system operates, the internal of rubber hoses are not smooth as compared to silicone hoses so when hot coolant is gushing through the hose(remember it is a pressurized system) it can form cavitations and air pockets within the flow and this passing through the radiator can reduce the efficiency in which, with silicone hoses, they promote a smooth flow of coolant thereby causing no cavitation or air pockets which inturn makes sure you are not sapping away at the cooling efficiency.
Another point for silicone hoses is they can withstand much much higher pressure than a rubber hose without rupturing. The levels they can withstand are much higher than the pressure build-up that's possible in most cases for motorcycle usage.

5) Also keep an eye on your coolant level, coolant just live water can also evaporate, and in many bikes, the coolant overflow tank is kep t in locations that are inaccessible to have a quick look(I'm looking at you, Honda), running a bike with low coolant also is a big reason why you bike is running hotter than it needs to be and this also puts more stress and wear and tear on your cooling system and also your engine internals, remember a modern engine has much tighter tolerances and uncontrolled or unwanted heat expansions is not something they are designed to take.

6) While removing the thermostat is not advisable, what a lot of people do(usually when getting an ECU flash) is to set the trigger point for the radiator fans at a lower temperature setting than whats set by the manufacturer, while there is a case to say that it might reduce the life of the radiator fan, I feel its a fair compromise if you have to replace a fan in 5 years when ideally it might have run 7 years.

Cheers
Krishna

[CrAzY dRiVeR]

Originally Posted by Jeroen

So what is the actual problem that needs solving? Do these bikes overheat?

What does the manufacturer recommend?

Jeroen

They don't overheat

However, since you are sitting right over the engine as is the case with most motorcycles, the normal working temperature of a big motorcycle can get quite uncomfortable- especially at low speed situations.

Some (like Ducati and Harley) more than the others

[Jeroen]

Originally Posted by CrAzY dRiVeR

They don't overheat

However, since you are sitting right over the engine as is the case with most motorcycles, the normal working temperature of a big motorcycle can get quite uncomfortable- especially at low speed situations.

Thanks. What does the manufacturer recommend? I doubt very much it is de-ionised water these days. You can’t compare racing with daily use of a bike.

Do the math on how a coolant systems really works and you will notice that the specific heat capacity is a tiny factor. Air flow (speed) and engine rpm and engine loading are much more relevant. Dirt and dust build up on your radiator is a huge factor as mentioned as well.

Jeroen

[freelancer6202]

Originally Posted by drsureshmohan

Other jugaad trick is to remove the thermostat valve from the system that starts circulation of coolant straightway (I won’t risk that).

I will be glad to learn more from the group.

Thermostat is needed to stop instant circulation and allow engine to reach optimal operating temperatures, needed for better efficiency. It might keep temp. down but it seriously affects efficiency and once coolant heats to usual temperatures there is no benefit of not having a thermostat.

Heat shields are expensive but slightly helpful. Riding pants help with tolerating heat in moderatly hot climate. My way to deal with hot weather is to keep bike inside and use a beater car for city and slow use. I take out my 959 only at night during summer.

As a ducati owner(crazy heat) constantly searching for cooling options, I was wondering about a thermoelectric cooler for engine casings. Can someone more aware of that topic shed some light on Why isint that a viable option for external engine cooling since thermoelectric coolers can operate on 12v supply also ?

[drsureshmohan]

Originally Posted by Jeroen

Thanks. What does the manufacturer recommend? I doubt very much it is de-ionised water these days. You can’t compare racing with daily use of a bike.

Do the math on how a coolant systems really works and you will notice that the specific heat capacity is a tiny factor. Air flow (speed) and engine rpm and engine loading are much more relevant. Dirt and dust build up on your radiator is a huge factor as mentioned as well.

Jeroen

Manufacturer recommends coolant :water 50:50 for a wide audience from novice to expert where u fill it and shut it for 3 years . In Chennai heat plus traffic due to the ability of water wetter to wet the heat transfer surface by 50% I’ve noticed a good 10 degree reduction and I’ve found myself much more comfortable .ive tried on several motorcycles but yet to try on my new Hayabusa

[RodRowdyBiker]

Thanks for the post! I never know about de-ionised water + water wetter combo. Do you know by how much does the water wetter increases the boiling point of water? And what is the recommended ratio?

On a side-note, I found out that having low idling speed (it drops over time, known issue in most Z900s) somehow does not play well with the engine temps and in stop-start traffic, it can actually prevent the bike from starting up. I have been trying to figure out why that could cause the issue but I haven't figured it out.

[drsureshmohan]

Originally Posted by freelancer6202

Thermostat is needed to stop instant circulation and allow engine to reach optimal operating temperatures, needed for better efficiency. It might keep temp. down but it seriously affects efficiency and once coolant heats to usual temperatures there is no benefit of not having a thermostat.

Heat shields are expensive but slightly helpful. Riding pants help with tolerating heat in moderatly hot climate. My way to deal with hot weather is to keep bike inside and use a beater car for city and slow use. I take out my 959 only at night during summer.

As a ducati owner(crazy heat) constantly searching for cooling options, I was wondering about a thermoelectric cooler for engine casings. Can someone more aware of that topic shed some light on Why isint that a viable option for external engine cooling since thermoelectric coolers can operate on 12v supply also ?

If you find time just flush the coolant , fill with de ionised water and water wetter ; u should get at least 15-20 F decrease in engine heat . Pls let me know if you do it

[freelancer6202]

Originally Posted by drsureshmohan

If you find time just flush the coolant , fill with de ionised water and water wetter ; u should get at least 15-20 F decrease in engine heat . Pls let me know if you do it

There is a ducati owner here who did this and said there was only marginal.

"One thing that anyone who has been reading this thread knows, is the heat from the bike. I had last year done a coolant flush and used Engine Ice, but had very quickly realised it probably is not the best choice for 959, it heats up very quickly and cools down quickly too, but the bike gets very very hot in city traffic." :'(

I will try water watter and ionised water as you suggested.

[drsureshmohan]

Originally Posted by freelancer6202

There is a ducati owner here who did this and said there was only marginal.

"One thing that anyone who has been reading this thread knows, is the heat from the bike. I had last year done a coolant flush and used Engine Ice, but had very quickly realised it probably is not the best choice for 959, it heats up very quickly and cools down quickly too, but the bike gets very very hot in city traffic." :'(

Engine ice is a flop for hot countries ( you can read the reviews ) it’s nothing but propylene glycol( non toxic and pet friendly suitable for USA weather where most diy and have pets at home) .Engine Ice is often considered not as effective as traditional coolant because while it can lower the coolant temperature in the radiator, it doesn't necessarily transfer heat away from the engine as efficiently, potentially leading to higher cylinder head temperatures . I tried the expensive engine ice coolant in the month of February! on my ninja 1000 and my thighs were getting a good heat treatment . 5 litres of de ionised water costs 400 rs and water wetter would cost Rs 1000 which will last 5 yrs ( the bottle ) but you MUST flush every year ( not meant for people who don’t like to tinker) . My ninja engine temp would not cross 3 rd bar . On the rare event of all the bars coming on the time for recovery I remember was very quick as compared to regular coolant + distilled water.

You may want to see the dyno results in the pic I’ve attached