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Pavloszx

Sherco st 300 operating temp

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6 hours ago, Pavloszx said:

Does anyone knows what is the radiator operating temp and exhaust temp? 

You will ....when you use a digital thermometer to find out.

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The optimum engine operating temperature is 72.5 degrees C be that two stroke or four. That is what an engine tuner will aim for to obtain the best power. Most manufacturers have to take into consideration all of the emission regulations current at the time of manufacture, so you may find that the thermostat is marked 80 degrees or higher, possibly approaching 90. As water boils at 100 degrees C you don’t have much margin, however with the cooling system pressurised by the rad cap the internal temperature will be more like 120 degrees C, that’s why the coolant sprays out everywhere if the cap is removed before allowing to cool down; the coolant literally expands having been pressurised. Coolant under pressure has a lower temp until it reaches the atmosphere then watch out. Because of this pressure less water can be employed thus saving some weight. Add to this an anti freeze, that lowers the freezing point but more importantly raises the boiling point and you have the benefit to use less water still. Confusingly Sherco show and list their thermostat as a temperature or thermal/ thermo switch. This should make electrical continuity at the terminals when immersed in water at a temperature of 90-95 degrees C which should when fitted to the engine turn on the cooling fan. Ensure that you have the correct coolant mix and don’t just bung in any old anti freeze it has to be compatible with aluminium. A good thermometer or better still a digital volt meter with temp probe will give you an accurate idea of the temperature🙂👍

PS if you can obtain a switch with a lower temp say 78 degrees you will be saving on engine wear in the long run. An alternative is to hard wire the fan so it is running all the time, this may not be suitable for you but I’d be comfortable knowing it’s on rather than worry about. Exhaust temp is difficult as it depends on how hard the engine is working and how much exhaust gas is flowing ie high revs or low revs and whether you are in Motion on the road or track at speeds that generates a cooling effect or in section with little wind or air flow over the engine.

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I am asking about operating temp because the radiators go up to 100°C and the clutch side cover up to 90°C and i think it's to much

I ride in around 35°C 

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1 hour ago, Pavloszx said:

I am asking about operating temp because the radiators go up to 100°C and the clutch side cover up to 90°C and i think it's to much

I ride in around 35°C 

Wire the fan to run all the time ...not much else you can do without custom building a bigger radiator etc and adding cooling fins to the clutch cover 

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