Heading down to the local dealership tomorrow to get a new to me 01 yz426f. Looking forward to hitting the trails this weekend. From talking to other four stroke riders they say not to use regular motor oil, only the motor oil from the dealership, in these bikes because regular oil that you would put in your car would cause the clutch slip.... I'll will be sure to check this out with the mechanic at the shop but thought I'd see what you guy's have got to say on the topic. Thanks...

Yeah, that's the idea... 'Energy Conserving' automotive oils contain friction modifiers that cause wet clutch slippage. You'd do OK with Yamaha's Yamalube 4 20W40 oil or their semi-synthetic Yamalube 4-R 10W50. Better yet, Amsoil's synthetic 10W40 motorcycle oil for ultimate protection... Some like using Mobil 1's 15W50 'red cap' oil... Unless riding in hot conditions and/or racing, the heavier 50 weight would only bog you down.

There are MANY posts covering the whole oil issue.

There are three schools of thought here, and all of them pretty much have valid arguments:

Motorcycle-specific oil (Mobil MXT4, Yamalube 4 or 4R, etc). It is purported and in some cases documented that these oils have higher concentrations of certain additives which “may” prolong your engine or increase performance of your clutch.

High quality synthetic which does not contain "energy conserving friction reducers". One sign that the oil does not have these additives is that the API service ring on the back of the can does not say "ENERGY CONSERVING" in the bottom half of the ring. One such "non-EC" synthetic oil is Mobil 1 15W50 (it has a red cap).

High quality automotive oil (Castrol GTX, etc). Be sure that the oil does not contain EC additives -- check the API service circle.

If you change the oil frequently, as you should, you will not notice any difference in these types of oils. Moto-specifics are the most expensive and the generic auto oils are the least expensive. You can't go wrong following the manual recommendations and using Yamalube 4 (dinosaur) or Yamalube 4R (semi-synthetic) and many folks on TT use Mobil 1 15W50 non-EC and have good results as well. As a rule of thumb, pick an oil type which you can afford to change frequently, and you'll be fine

taken from:

The oil issue has more sides to it than a good diamond. Here's another one. Add this to the stack.

The American Petroleum Institute (API) puts service grading on all oils used in cars, trucks, etc. Until a couple of years ago, the best grade of oil you could get was API SG. SG has several very effective wear reducers in it, and is a good oil to use. Unfortunately, these wear reducing additives had sulphur in them, and according to the EPA, are bad for the planet. The API produced a modified specification, SJ, that removed the sulphur based wear reducers. SJ oils are often modified with the aforementioned "Energy Saving" friction modifiers, which do a better job of making clutches slip than of reducing engine wear for some reason. SJs also contain emmission reducing adds that aren't terribly beneficial to engine life, too.

Manufacturers of high perf motorcycles in Japan became disturbed that SG oils were off the market and went to the Japanese counterpart of the API, JASO (the exact def of the acronym escapes me). They came up with two oils for use in motorcycles that delete the newer emission reducers and restore the older, more effective wear reducers. Their grades are MA and MB. Both of these will also carry the API SG grading. You'll be surprised at the number of oils carrying MC brandnames that are graded SJ, and are not graded by JASO. JASO suggests that no SJ oils should be used as a high-performance or racing four-stroke lubricant.

Any MA oil is safe in the engine of a YZF, whereas the MBs carry more friction reducers, and are recommended only for engines like the CRFs that have their clutch somewhere else.

I use an MA oil, Golden Spectra 4. I am going to research the Mobil 1 RC option, though, because I have had very good results with M1 in automotive applications.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now