Evan Waterless Coolant

No thermostat leads to longer heat up time at starting from cold.

This will cause your bike to run longer on high fuel flow, metered by the ecu.

 

I don't think removal of thermostat leads to a much greater flow of coolant.

Only issue I have seen, is the engine taking too long to get up to temperature.

 

What rads have you tried? What was the bigger one that didnt fit?

 

Don’t run without a stat, you need to get to the bottom of the issue. Check the pump for flow and stat for operation. Water pump cover should match the impeller otherwise it won’t move as much liquid.

 

There is also a factor called "dwell time". It's not just about how quickly you can get water in and out of the radiator. It needs a dwell time factor to actually cool the fluid optimally .

 

if you remove the radiator cap when cold and start the bike, you should see a surge of fluid at the top, this is as the pump starts to push the fluid.
without checking a bike physically, on a car system you can hold the rubber hose and squeeze it and start the engine and you will feel the pressure of the system push against your grip on the hose.

 

You probably wont see much water movement, as the thermostat will be closed.

 

Rads = radiator

 

possibly, but if you squeeze ( not crush...) the output hose of the water pump you should feel the pressure build up.

i last did this on my Panigale as i was also trying to check function of the system components and check for hotspots/ air pockets as i had a overheating issue ( +107-110) so i did the above to confirm pressure build up, and cross checked in the In and Out of the radiator for temperature drop across it using a hand held measuring device

 

Better to use demineralised water.

 

Find out what the coolant capacity is, either use 50/50 mix or what suits your climate, but use di ionised (distilled) water because the engine is alloy and hard tap water can fiurr up water ways

 

I use tap water yes. Premix 2 percent Silkolene with 98 percent water in a jug. Some say use deionised. I was once told by a very clever engineer that the ions and other desolved solids in tap water transfer heat better. I never checked if that it true. What it a definite is that water is better at heat transfer than antifreeze.

 

You need to consider the chemistry of the materials and the engineering of the whole isothermal system in action, not just the thermal conductivity of the fluid component. If you start with tapwater, over time, it deposits unfavourable minerals as scale on the internal surfaces of the whole system, which acts as a real barrier to heat transfer. So, remove the unfavourable minerals, add a corrosion inhibitor, and if your system started off clean, it will remain clean and able to operate at peak efficiency.

 

My 2cents worth: There are many compromises in the cooling system. I think most people are overly anxious about engine running temps. Ideally the engine should reach mid range on the guage as soon as possible. Efficient engine running requires a hot engine hence the need for a thermostat.
Also, if you remove the thermostat the coolant can run too quickly through the engine and not cool properly. The design of the engine and water pump has been built with a thermostat for running at its best.
Water is the most efficient cooling medium but on it's own will corode the internal components of the engine. That's why anti-freeze/inhibitor is added. Be careful, anti-freeze/corrosion inhibitor is a poorer conducter of heat so only use enough to provide the protection you need and the balance should be de-ionised water. 50% AF is probably more than you need.
In my climate we don't need AF just the inhibitor and I am well aware of the heat from riding in traffic. If the engine is showing heat in any part of the guage it is OK. IF it hits the right side limit then that's too hot and you should stop and let it cool.
If you bike is running too hot in moderate heat (up to 35C) then check the efficientcy of the radiator (internally and externally) and that the fan is working properly.

 

Assuming the cooling circuit was well designed, you should normally not remove the thermostat.
The expected flow resistance from a closed or open stat are part of the designed system. If you remove them the pump may run off its curve (design limits for flow and pressure) and reduce pumped pressure, stall flow, cavitate, increase back-flow or similar.

 

This is a good scientific write up about the advantages and disadvantages of different cooling fluids including tap water and deionised water etc.
I found it interesting.
https://www.boydcorp.com/resources/temperature-control/best-heat-transfer-fluids.html