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Is there a study available that has which two stroke oil gives the lowest crank case temperature during hard use? To me, which ever one is lowest would be the most efficient lubricant. Sorry for this crazy question. This is only my second atv, and it's my first Polaris.

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No studies that I know of, but the type of two cycle oil mixed with the fuel has no bearing on crankcase temp - the temp of the crankcase is somewhat regulated by the temperature of the incoming air as there is no oil in the crankcase. The only oil in the crankcase is the oil carried in with the gasoline, so it more the amount of oil carried in that might affect temperature of the moving, heat generating parts. That's why the more oil you can mix with the fuel without fouling the spark plug the longer the parts will last and the more power the engine will produce.

If you have oil injection, the pump can be adjusted for more or less oil, but the adjustment is limited and the amount of adjustment just affects riding style. If you style is short bursts of wide open throttle followed by short periods of closed throttle (woods riding) the oil pump can be set to it's lowest setting. If your riding style is long periods of partial throttle settings (steady state speed - cruising on roads or cleared trails) then the factory recommended setting is best. If you are racing and the engine is subject to long periods of wide open throttle (more than 3 minutes without closing the throttle to idle or less than 1/2 open), then the pump should be set to it's maximum capacity. Also, you must use an oil approved for use in injection systems. At ambient air temperatures; a premix oil in an oil injection system may starve the engine for oil at low temperatures and over lubricate at high temperatures due to viscosity changes. An injection oil may be premixed, but a premix oil may not be used in injection systems.

Now, if the oil pump has been removed and you are running a premix oil, there are high quality oils than lubricate better than cheap oils. Most high quality oils will be synthetic, but most oils will not mix with alcohol. If you are using alcohol blended fuel, you must pay attention to whether the oil will mix with alcohol or not. Best to just use non-alcohol blended fuel (readily available at marinas as many boat engines are two stroke) and the 4 stroke motor boat engines don't suffer from alcohol caused corrosion of the valves, rings and cylinders when they use ethanol free fuel. Also, ethanol free fuel provides about 4% greater fuel mileage. Oil that will mix with alcohol is vegetable oils (castor bean oil) and specially blended synthetics.

With all that said, don't worry about the crankcase temperature. It is cooled by the air coming in through the carb. Temperature is not the problem - lubrication is the problem - too little lubrication and parts (rings, cylinder, rod and crank bearings) wear out quickly and at high speed simply burn up or weld themselves together. Too much oil and you waste oil, foul spark plugs and sometimes experience hard starting.

Any other questions?
 
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