TOPIC:

Thank you!

Interestingly, I hardly ever rev my bikes hard, but I have done so on occasion with the KZ1000P and right at the high end had some clutch slippage. I put it down to being an old clutch, but I will change the oil and see if it happens still. Good opportunity to change the oil filter as I don't think that I have ever done that.

Cheers
Paul

Hi Paul,

As a Bike Mechanic between 1977 and 1981, the motorcycle workshop I worked in would have at least 1 or 2 bikes in every Monday morning with clutches slipping............mainly due to owners doing an oil change over the weekend and using Castrol GTX or Duckhams or Esso Superlube CAR Engine oil instead of the correct oil for bikes with wet clutches.
The owners excuse was normally that they had used those oils in their CAR for decades and the clutch had never slipped .......HaHa.....LOL !!!!!!

Incidently, when you drop the car oil from your KZ1000, get the engine nice and hot first, so the oil is as thin as possible and leave it to drain overnight, to get as much out of the motor as possible before replacing it !

Pete F
UK

I don't think it mattered much back in the day but yes modern car oils contain friction modifiers to help with fuel economy. A good quality mineral or semi-synthetic motorcycle specific oil is recommended.

OMG! An OIL Thread!

I'll tell you what I was told when i got into first-gen Honda Gold Wings. All oils up to 10W-30 use friction modifiers, which can be verified by checking the round certification stamp. If it says anything about Mileage at all, it has FMs and may cause your clutch to slip. 10W-40 and up are considered to be made for vehicles so old and crude that they have no use for FMs. They will have no mention of Mileage on the round stamp.

I was also told that 100% synthetic Mobil One (which I use in EVERYTHING, even my lawn mower) is so slippery that regardless of the stampings, etc., it may make your wet clutch slip. There were always dudes who claimed to have used M1 in their Gold Wings since God was a young man, and never had a problem, though.

In my case, I compromised on Valvoline semi-synthetic 10W-40, which I buy in 5-quart jugs at Bi-Mart. I often pop the clutch on my Gold Wing at full throttle, 8000 RPM, and have never experienced anything like clutch slip.

When I got my first KZ1300, about a year ago, I announced my intention to use the same oil in it, and got some thumbs up from the 1300 fraternity. The bike isn't finished, and hasn't been ridden extensively, but if I snap the throttle open and closed, the front tire comes up about 2" off the road with no signs of clutch slippage.

I am a huge believer in the ability of synthetic oil to essentially arrest all frictional wear, and even extend the redline a judicious amount.

I also think there is nothing to the argument that "these bikes were specified to require XYZ dinosaur oil in the manual, so that's the best for them, end of story." That's nonsense. Advanced oils just weren't available in the early 80s. If they had been, I have zero doubt that the design engineers of these highly-stressed engines would have leapt at the chance to recommend a better lubricant.

If you know anything about me by now, it's that I research the hell out of problems to find viable solutions so here we go.
The Service Manual tells us to use a good quality SE grade motor oil. Se Grade is an American Petroleum Institute grade of motor oil and In research became an obsolete grade of motor oil for internal combustion automobile engines as of 1979. So we need a new Standard for oil for our motorcycles.

JASO (Japanese Automotive Standards Organization) is an organization consisting of major vehicle manufacturers in Japan. It was created as the Japanese equivalent to the API (American Petroleum Institute) specifications because those were not suitable for the unique specification needs of modern Japanese engines. The API specifications are constructed for automobile engines but not for motorcycle engines.
Car oils have been used up to 1998 as the base for most motorcycle oils. But as the technology in cars evolved, the oils were modified to meet those modern needs. As a result, additives were added and friction modifiers were blended with the oil. Although these modifications were positive for use in cars, they were damaging to motorcycles. This was especially the case with motorcycle gearboxes and clutches. Unlike with cars, motorcycles don’t use a separate oil for the gearbox, causing the clutches to slip due to the friction modifiers. It also could attribute to gearbox pitting (localised corrosion and the formation of micro-cracks). Oil in motorcycles and scooters is required to run under more intense conditions than in cars because it has to endure hotter temperatures as well as higher engine speed and a greater power density. These circumstances subject the oil to significant operating stress.

In 1998 JASO T903 was introduced as the globally recognized standard for 4-stroke motorcycle oils. It defines the required performance levels for satisfactory lubrication of the different motorcycle designs.

JASO T903 consists of two performance categories:

JASO MA: Oils for motorcycles with a wet clutch. These oils deliver the needed friction performance to prevent the clutch from slipping and are therefore non-friction modified. These oils can be used in 4-stroke motorcycle engines where there is one oil system in place for the engine, gearbox and clutch. MA oils are suitable for all applications.
JASO MB: Oils for motorcycles with an automatic transmission (scooters). These oils deliver the needed friction performance by added friction modifiers which provide fuel economy benefits. These type of oils are ranged as the lowest friction oils in 4-stroke motorcycle oils. MB oils should not be used when a MA oil is required as they could induce clutch slippage in motorcycles and should therefore only be used in scooters. The transmission in scooters is done by use of belts or chains and does therefore not require any oil.
An oil is either MA or MB based on the outcome of the JASO T903 Clutch Friction test. In this test the performance of three friction performance areas is evaluated, making sure the oil is suitable for wet clutch applications.

Dynamic friction: The feel of the clutch and the power transfer during clutch engagement.
Static friction: The capacity of the torque handling and the resistance against slipping during breakaway conditions.
Stop time: How quickly the clutch is engaging.
The main difference between JASO MA and MB is whether the oil is suitable for a wet clutch or not.

In 2006, MA1 and MA2 were added as extra categories within the JASO MA specification. The main difference between these two categories is the higher friction performance MA2 oils are delivering. This meant that from 2006 on, motor oils that meet the T903:2006 standard can be divided into four specifications for 4-stroke motorcycle oils:

JASO MA: This is the standard specification for oils that are used within one oil system (where the engine, gearbox and clutch use the same oil). These oils don’t contain any friction modifiers.
JASO MA1: This is a lower standard specification for motorcycles that require different oils for the engine, gearbox and clutch.
JASO MA2: This is a higher standard specification for modern motorcycles. These oils are suitable for use in motorcycles that have catalytic converters in the exhaust system.
JASO MB: This is a lower standard specification for scooter engines.
For an oil to meet any of the above mentioned JASO specifications, it has to meet at least one of the following quality levels:

API SG, SH, SJ, SL, SM
ILSAC GF-1, GF-2, GF-3
ACEA A1/B1, A3/B3, A3/B4, A5/B5, C2, C3
Although the above motorcycle oil specifications are by far the most important and worldwide recognised, JASO already introduced a rating system for 2-stroke oils in 1994. The tolerances of modern 2-stroke motorcycles and scooters are much smaller and also require an oil that generates less ash.

Excellent job!

In your researches, did you come up with a reference guide that would 1) let you look up a given standard (say, JASO MA) and get a list of oils by manufacturer that meet that standard, and 2) look up an oil by manufacturer and "friendly name" (i.e. the name printed on the bottle) and see all the standards it meets, even the ones NOT printed on the bottle?

Richard