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Discussion Starter #1
Hi everyone. I bought a used 2000 model in 2004 and instantly found out about cam lobe wear problems with Polaris 500 HO's and as a result, replaced the engine. The mechanic told me that you should not idle 500 HO's long because it will ruin them. Is that correct? If so, why Thanks for your advice.
 

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You should not let any ATV, motorcycle, snowmobile, jet ski and many other types of engines idle more than 5 minutes after it is fully warm (normal operating temperature). My rule is if it is going to idle any longer than it takes to pee, shut it off. At idle the oil pressure is low and the hottest part of the engine with parts that are subjected to the highest shear forces (cam and rocker arms) is cooled by oil - the cam is at the uppermost part of the engine and heat rises. While the coolant is regulated with a thermostat and fan, the oil carries heat away from the top of the cylinder head to the crankcase where it is pumped into the oil tank - the oil is cooled by the surface of the tank (which may be metal or composite) - at idle there is no air movement around the oil tank and the oil temperature rises - as the oil heats it is easier to shear the molecules in the high metal to metal pressure contact areas. Again; cam and rocker arms.

It's actually hard on all engines to idle for long periods except engines designed for long periods of low speed operation. Those so designed engines have a large capacity oil pan (maybe as much as 5 gallons), high volume oil pumps and an oil cooler in addition to a coolant radiator. Those engines also run a special grade of oil.
 

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You should not let any ATV, motorcycle, snowmobile, jet ski and many other types of engines idle more than 5 minutes after it is fully warm (normal operating temperature). My rule is if it is going to idle any longer than it takes to pee, shut it off. At idle the oil pressure is low and the hottest part of the engine with parts that are subjected to the highest shear forces (cam and rocker arms) is cooled by oil - the cam is at the uppermost part of the engine and heat rises. While the coolant is regulated with a thermostat and fan, the oil carries heat away from the top of the cylinder head to the crankcase where it is pumped into the oil tank - the oil is cooled by the surface of the tank (which may be metal or composite) - at idle there is no air movement around the oil tank and the oil temperature rises - as the oil heats it is easier to shear the molecules in the high metal to metal pressure contact areas. Again; cam and rocker arms.

It's actually hard on all engines to idle for long periods except engines designed for long periods of low speed operation. Those so designed engines have a large capacity oil pan (maybe as much as 5 gallons), high volume oil pumps and an oil cooler in addition to a coolant radiator. Those engines also run a special grade of oil.
THANK YOU!! for your detailed reasoning about the idling and potential damage it causes. I really appreciate you r responding to me.
 

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don't overthink the whole problem,even 30 min idling won't hurt a thing in your engine
You treat your engine your way and I'll treat mine my way - I haven't replaced a cam in any of my engines (motorcycle, ATV, utility or automotive) in over 50 years of vehicle ownership. I'm either lucky or skilled - either way, it has worked to my advantage. I have replaced pistons and cylinders due to seizure and I was aware of the circumstances when it occurred and know what I could have done to prevent it, but it was under the circumstances that I consciously let it happen knowing what the result would be and it wasn't idling that did it, but idling could do it too.
 

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don't overthink the whole problem,even 30 min idling won't hurt a thing in your engine
I appreciate your comment and I know that there are a lot of facctors involve in damage potential. I was looking for sound reasoning as to the difference between a vehicle and a 4X4 as far as potential damage and why or what would be the source of it and the above explanation helps me a lot.
 

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Discussion Starter #9
I was told by the mechanic at the Polaris dealership that soft cams were a problem Polaris had at least in 2000. I was then worry about where that metal went and didn't want to trust that there was no other damage. Besides, trying to get ready for a long weekend adventure with fried and it was the quickest and most assured recovery to kind of insure no secondary problems on that weekend drive.
 

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why would you want to let the engine run longer than it takes to take a piss. We go to the outdoors to enjoy the sound of nature not the engine running. If you are riding with us we will tell you to turn the dam engine off.
 
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