Stick with Honda OIL it's more expensive no question, but it's what your machine craves...it has all the vitamins and minerals to keep your quad happy for a long time...

 

That filter is terrible...geez, only a Honda could last with that thing!!!!!

 

E-mail me that pic of that filter..I gotta see it...5 years old man.......

 

I don't know what weight for a 400ex, but I am happy with Valvolines ATV oil. I buy it at a large oil disrtibutor for about $2 qt.

 

I know (well at least for your sake) your being completely sarcastic , but [img]i/expressions/face-icon-small-smile.gif[/img]

Allways thought of it this way. If you are inclined to be changing your oil every 3-5 hours then just run any quality motor oil that fits the vis requirements of the engine and temps etc. but if you like to extend your intervals for oil changes then consider the full synthetics as they hold up much, much longer before any breakdown of the oil itself.

Now there is a lot more to oil selection than that simple idea above but this is where all the bs controversy starts and the real issue starts to become cloudy.

I have worked with some people in the petroleum industry and most all have claimed that 98% of the claims that a quality auto synthetic oil will not perform in a wet cluth application is completely bogus. Never did get any info on the other 2% but since I have had nothing but great experiences with everything and anything that I have poured mobil-1 into I never bothered to pursue the info.

I have also found that for use in a higher temp engine that will see demanding use like you would see in a modded 400ex or even a 4cy import for that matter you will get much longer "useable" life from a quality synthetic oil. What is important about that to me is that your engine will still get the proper lube it needs even when the engine is running super hot, or when you were rushed and couldnt get it changed out etc. The extra breakdown resistance is a real insurance policy.

BTW except for break in on new parts etc where I normaly have run GN4 I use mobil-1 on everything I own with the exception of some old leakers lol, but you get the idea and I have had ZERO complaints.

Look around and you will find constant disagreement on this topic and in the end you will run what you like or what you have tried and received good results from.

 

Mobil1 15w50 works very well.

Lesser oils WILL break down quickly in the 400EX and leave you smoking on decel.

Why not then run a BLEND, and get the BEST OF BOTH WORLDS

A blend is NOT the "best of both worlds". Blends were developed strictly to meet a price point, not because they offer any advantages over a full synthetic oil.

Are there better oils than Mobil1?

Yes. However, for me Mobil1 has many advantages over the others.

1.) It is a very good oil, it has no viscosity improvers, does not contain friction modifiers, has cold pumpability better than most conventional 5w30's and higher flash point than most other oils...

2.) Fully synthetic blend of 3 synthetic base stocks.

3.) Easily obtainable - it can be picked up while you are at walmart.

4.) Cost - about $4/qt, same as the most of the cheapest conventional "Motorcycle" oils.

 

I was wondering if the Mobil 1 15w-50 will work in the hot days of arizona 90+ almost year round in the winter around 70-80 and summer most of the time 100+.... I was wondering if i should get diff weight or will 15w-50 work?