I have a '99 400EX and I am getting ready for winter here in Minnesota. What oil weight should I run? The manual says SAE 5W for temps 50 to about zero. I have been using GN4 10W-40 with no problems, and I've been told that 10W-40 would be fine once the engine is warm. Should I switch down to 5W, or stay at GN4 10W-40? The lowest temp I would ride would probably be -10 degrees.

 

Doesnt matter how cold it is when you ride. It is starting temp that counts.. If you are starting it at anything below 0 I would get a full snythtic 5W or even 0W30.
Joe

 

after thinking even more on this, If I was you and wanted to ride at -0 temps I would pore Amsoil 0W30 in it. Even if it gets warm for a week or two the snythtic will be as thin as lamp oil but will still protect prefectly

 

You should run an oil that's made for off road vehicles, don't use an automotive oil. Also, I don't know if sythetic would be good in your case because of your manual clutch. Synthetic oils tend to be slippier than regular ones, so you might have some clutch slippage. I use Honda GN4 10W 40 in the winter.

 

you might want to look into a dipstick crank case heater that plugs into ac.It will keep your 10/40 oil at a nominal viscosity unti you start your quad.J.C.Whitney catalog shows a magnetic mount oil pan heater that can be placed on any point of the engine that will heat up to 250 degrees. About $25

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THE AZ HARD PACKER, calmiller@kachina.net

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