Polaris trail boss 330 oil suggestions

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10,630
Location
Jupiter, Florida
The Polaris Trail Boss has a SOHC 2 valve Robin air cooled engine with oil cooler and fan. The engine has no gearbox, as the transmission is a belt. It requires 0-40 SH synthetic oil. Here in South Florida, where it was 96 degrees at my house yesterday, I think that oil is a bit thin for an air cooled engine. It is a fairly low RPM engine and does not make big HP numbers. But a quick dipstick check shows water thin oil. Even though the engine is a low stress engine, it does get used hard. Also remember that it was designed in Canada, where the yearly temps are quite different to my local conditions. I have been considering using Delvac 1 5-40. What do you think? How about MX4t 10-40. As the engine only holds 2 quarts, and oil changes happen once a year, cost is not really an issue. Quality and oil performance is. Chris
 
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2,591
Location
MN
Cujet, Aren't the Polaris engines made by Fuji Industries? I've never had any problems using Amsoil 0W40 in a Polaris engine. I use it year round here in temps ranging from -20 to 100 without any problems. I see Polaris is spec'ing 0W50 for the new Hawkeye ATV. In Florida you could probably use a 10W40 because it doesn't get that cold, but I don't know that it is going to be any better than a 0W40. The 0W40 is going to protect better at startup and be about the same weight at temperature. Any oil is going to look like water when hot in an air cooled engine.
 

Cujet

Thread starter
Messages
10,630
Location
Jupiter, Florida
Thanks for the reply, The engine says Robin on the emissions compliance sticker. Is Fuji the parent company of Robin? This I do not know. I do not think there is much start up flow risk with slightly thicker oil here in South Florida. But who am I to say? What do you think about using Delvac 1? I have quite a bit of this oil. Chris
 
Messages
2,591
Location
MN
I guess we are both right. Subaru Robin's parent company is Fuji Heavy Industries. Subaru Robin I think you are fine with any 40W oil, be it 0 or 10W. These engines have been around a few years and are pretty reliable. I wouldn't worry too much. Like I said, I use Amsoil 0W40 year round without problems. The Amsoil is readily available around here.
 
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