Can I use regular car oil in my 99yz400. Like maybe a synthetic car oil or something?

Yes. The thing to be aware of is using oil with friction modifiers. The most common and popular oil for the 400/426 is Mobil 1 10w50. Using the wrong oil will cause clutch problems. Honda realized this problem when the CR450 was designed with the separated engine sump and transmission/clutch lubrication systems. Hopefully, Yamaha will follow suit in the future. It would seem foolish if they didn't.

Boit, is this true? You can use regular car oils like Mobil 1? Does it have to be synthetic? What about Castrol or oils like that? I've heard many mags and manufacturers endorse only top quality motorcycle lubes. I'd be interested to see who here in this forum uses Mobil 1 or something like it in their Thumpers. I use Yamaha 4 Cycle, the stuff they recommend of course. I'd love some feedback on this. Thanks.

Good article. I might also correct two mistakes in my previous post. The Mobil 1 synthetic oil I meant to refer to is, of course, the 15w50. . . not 10w50. The other mistake is that I wrote; "using the wrong oil WILL cause clutch problems". I shoud have written. . . "COULD cause clutch slippage problems? I don't think Mobil 1 10w30, 5w30, or 0w30 are good choices for wet clutch applications. All those oils have the 'Energy Conserving' notation in the API symbol.

The oil issue seems to be an ongoing one. Recently, someone posted the results of an independent test on oils for motorcycles. If may not have been posted in TumperTalk, but possibly www.Dirtrider.net . According to the results, Mobil 1 MX4T 10w40 fully synthetic 4-stroke motorcycle oil performed at the top of the list(If my memory is correct). Also, if my memory serves me right, Valvoline did not perform very well and Castrol was somewhere in the middle.

I've got a 01' YZ426 and myself and two of my buddies just switched to Mobil 1 15w50 from Yamalube 4R. I'll let you guys know our results. Here is a good article about Motorcyle oil, and there is a list of NON Energy Conserving SJ oils at the end of the article that is quite helpful. http://www.yft.org/tex_vfr/tech/oil.htm

My friend is going to get me a couple of oil analysis kits for free and I'm going to use it on my Explorer and my YZ400. I have run Mobile 1 15/50 in it since I bought it in Sept of '00. The original owner ran Yamalube 4R. The Analysis kit will show all of the materials in the oil. I'll post the results of the YZ400 test and the Explorer test when I get them since I run Mobil 1 15/50 in it also. The Explorer has had Mobile 1 sythetic in everything since it was new in '92. Motor, trans., transfer case, and difs. Never a problem with any and I'm sure you all have heard of Exploders, they got the name for two reasons: Firestones and Trannies that like to blow up with under 100K on them.



"What's that?"

"It's a Yellow 99' YZ400!!"

sirhk: In my opinion, the oil analysis is probably the best way to go. I plan to do this as well.

Interesting articles....... One thing I wanted to point out and I'm not sure who to believe on this, but as far as viscosity weight goes....... One article says that a 20/50 works better since it offers more cushion and a 10/40 allows the bike to have less resistance, therefore more power, but more wear...... Well, I spoke with a Golden Spectro Rep and he said that the 10/40 Spectro Synthetic is a better oil than the 20/50 because the molecules are bigger in the 20/50, therefore not able to lubricate as well. He also pointed out the fact that many motor manufactures (Honda in particular) recommends 5/30 in their cars because it lubricates very well and also doesn't robb the engine of power. He said the same principle applies in motorcycle engines. Any thoughts on this? I run 10/40 Yamaha 4R in my 426 and I have no complaints. I get it for about 2.50 a quart, so it's very reasonable when making oil changes. I know Synthetic is more expensive, but since my convention oil doesn't have enough time to break down after two practices, why run Synthetic in the first place? Doesn't it make more sense in cars and trannies that are going 6000 miles between oil changes? Any feedback is mucho appreciado.....thx.

Interesting slants and opinions on the oil issues. When it comes to selecting an oil for ou 426, we need to keep one thing in mind...OUR CLUTCH. With that being pointed out, we can proceed. If we had a separate clutch/transmission sump ala Honda, we could select the appropriate oil easily, but we can't. So, we are left with selecting an oil that is used in both the crankcase and transmission/clutch sump. How do we know what to use? Excluding oils with friction modifiers, we can use any quality grade synthetic oil. If you use an oil that seems to cause clutch slippage, stop using it and change to a different oil. If it doesn't improve, change the fiber plates..or the whole plate assembly and try a dino oil. It really isn't that hard. What makes sense to me is to use what works for the vast majority of 426 owners.

I've been using Bel Ray EXS 10W50 Superbike oil that is aimed at the high revving sport bike market. This oil was purported to assist with notchy shifting....and it has....plus, it's fine for wet clutches. So far, I haven't found anything better....but haven't tried the Mobil 1. Not much help, I suppose.

[This message has been edited by Boit (edited 07-12-2001).]

[This message has been edited by Boit (edited 07-12-2001).]

MotoStyle, I was told that Yamalube 4R was a full synthetic, is this not true?

Also some time ago I wrote to Spectro about a lable on the bottle and the following is my email and their reply. I was impressed that they took time to reply. I thought that this may be somewhat educational to you guys (it was to me). As a side note for reference, my 01' manual says on page 3-14 that the recommended oil is marked API "SH" or higher grade, "Designed primarily for motorcycles".



-----Original Message-----

From: <Edited>

Sent: Wednesday, June 13, 2001 8:51 PM

To: spectro@snet.net

Subject: bottle labels accurate?

I have purchased some of your "Golden Spectro 4" synthetic blend oil. The

label on the bottle has it marked as sf/sg but your web site says that it is

good for sh applications. Is the label inaccurate or is the error on your

web site?


<Name Edited>


Thanks for your e-mail!

Your observation is correct...here is a short explanation of the situation.

After the API SG period, the API made some changes to the limits on

additives that we, as a motorcycle oil manufacturer did not agree with, for

implementation during the SH period. These restrictions became more intense,

and fuel efficiency tests became more difficult to pass for SJ approval and

manufacturers were forced to use lighter oils and friction modifiers to meet

the new SJ fuel efficiency tests.

We decided to halt placing the API symbol on our products since this would

mean we would have to limit our formulations to meet these new automotive

derived needs. Further, we decided to continue to produce the SF/SG

formulation that we always made since we know that it is superior for

motorcycles.(and this has been confirmed by almost all motorcycle

manufacturers worldwide by their broad recommendation to use SF/SG oils in

their bikes.)

For a while, the API refused to allow even this SF/SG designation to be

placed on a label! Their reasoning was that it was not their current rating.

They then realized the reason we were doing it and then allowed SF/SG to be

put on the label without their "donut" logo since our oil is primarily

recommended for use in motorcycles.

Now, if your engine manufacturer requires API SH, we meet and pass all those

tests too. Except,we do have anti-wear additives in our oil that are over

the limit for the SH requirements but we are very confident that

recommending our oils for you with these extra additives is the right

recommendation for a motorcycle application.

Our full synthetic race oils do not exceed the upper limit levels of these

SH anti-wear additive restrictions and therefore have the API SH on the


If you need any further information regarding our labeling and API

qualifications, feel free to call us toll free at 1-800-243-8645..ask for


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