what type or weight oil should i use?

[atvtrailer]

what type or weight oil should i use for a 2002 400ex?

[mod81]

that bike has used belray thumper 20w50 since new...

[big-daddy]

take a look in the manual but I think more like 10w40

[TOY_DOCTOR]

Listen to Mod81, with the heat in florida you want to run a heavier weight oil, 20w-40 or 20w50, leave the 10-40 in your car..

[atvtrailer]

Ok, thx tracy i tried calling you last night but no one answered.

[big-daddy]

As usual, everyone has their own opinion on oils. I believe everyone should run what they feel is the best oil and weight and I don't try to sway them one way or the other. But, I have to disagree with using multi grade oil period. Your statement that 20w/50 is better because of temperatures. I think it means you have the protection of 20wt at zero degrees and the protection of 50wt at 210 degrees. Think about it..... Doesn't oil pressure decrease dramatically as the temperature of the oil increases? Isn't this a sure sign the oil is getting thinner? If it gets thinner, doesn't it pour easier? If the oil does have a reverse viscosity index as you suggest, then at what temperature does it become 20wt? 30wt? 40wt? 50wt?  I don't use multi-vis oil except when breaking in a new engine and then I run 10w/30 for the first 10 miles only. My opinion: When hot, multi-vis oils don't provide as much rod bearing cushioning as straight weight oil does. Try this: Get a can of 40wt and one of 10w/40. Put them on the same burner of a stove and heat them to 200 degrees. Which pours slower? The 40wt does.... a whole lot slower. A sure sign the oil is thicker. If it's thicker, it's got to have better cushioning on loads. This cushioning is needed if you're running hour after hour at high speeds when the weather is above 70 degrees to prevent undo pounding on the bearings. I agree the oils today are FAR superior to the old oils due to better refinement and better additives. I also agree the thinner oils are better on initial start up since they get to all the oiling points a lot quicker. Another point I would like to make. I believe the use of multi-vis in our quad is okay as long as it's cool outside and the trips are short and the engine isn't run at sustained rpm's above 2500 rpms. If you're curious, I run 40wt Valvoline in the winter and 50wt Valvoline in the summer on all my race engines.

Please note that, as usual, these are just my opinions....

[mod81]

so which is it ??you recommend 10w40min your first post the contrdict yourself in the second post by saying you only run straight weight...i have maintained the quad in question since new and it has used the oil i stated,not saying its right ,wrong,or indifferent but thats what its had in it from the start....no problems,can't argue with that...

[big-daddy]

mod81, what I said was look in the manual . Toy_doctor recommend 20w50 because of florida heat and thats is opinion. my opinion different, but thats mine! Toy_doctor builds some nices Quads and it works for him. Next time you have a change talk to someone that builds full race engines ask him what multi-vis oil he use. or go to your local speed shop an ask for pure racing oil and see what he bring you. again thats my opinion. God, I love America! you get to express your opinions without getting shot. Have a great day and enjoy riding your Quad. Toy_doctor love that Quad  

[mod81]

i agree witha straight weight for racing only(a race motor that has been clearanced and blueprinted for racing purposes only)i build race engines for a living ;Dyou stated you use valvoline race oil?if so read the disclaimer on the bottle,very few quads are used for racing only...what you say is true concerning oil in race engines as far as cushioning goes,the motorcycle industry is a lil bit different with the pin,rod,crank bearings being roller instead of babbit that exist in other motorsports....if you want to do some real research on oils see what weight oil is used in aircraft turbines at many times over the heat and rpm of a combustion engine...i build 10k rpm engines that run on methanol and are lubricated by a straight 10w oil with cylinder head temps of 450 degrees (no problems with protection)if want to talk race engines pm me for my phone number......

[BIGWORM3699 ( ECP RACING)]

MULTI IS THE WAY TO GO WITH OVER HEAD CAM NEED QUICK OIL PRESSURE TO CAMS SO THEY DONT RUN UNLUBED, THATS WHY YOUR SEEING THE WEIRD MUTLI OIL LIKE 5W20 AND SOON 0W20, IM IN THE AUTO INDUSTRY AND HAD THE CHANCE TO TAKE A CLASS ON OIL AND THIS IS JUST THE EASY, FAST WAY TO DISCRIBE THE WAY OILS WORK. BUT THE QUICKER YOU GET OIL TO THE TOP THE LESS WEAR ON CAMS, THE REASON TRUE RACE ENG. USE STRAIGHT WEIGHT IS ITS GOING TO BE REBUILT WAY SOONER AND ITS ABUSE IS MUCH HIGHER.IF YOU WANT IT TO LAST A LONG TIME MULTI IS THE WAY AND SYN. OIL IS MUCH BETTER THE BASE STOCK NEVER BREAKS  DOWN, THE ONLY REASON FOR CHANGING THE OIL IS IT GETS DIRTY. HOPES THIS HELPS IF NEED MORE INFO CONTACT MOBIL OIL THEY HAVE THE BEST BREAK DOWN OF INFO  

[dvx400#1]

this is what i say have what ever oil you like,  and have lucas oil can't go wrong  

[big-daddy]

is that like the prince of darkness lucas ?

[LTZ400ApK]

Replace it with sand you dont have to change it as often