8
FUELS & LUBES INTERNATIONAL
popular with women, according to
Kumar.
The current motorcycle
oil specification is Japanese
Automobile Standards Organization
(JASO) T903: 2011. JASO MB is
recommended for scooters. The
specifications are currently being
revised, said Yashiro Yoshinobu
of Yamaha Motor Co., the second
largest motorcycle producer in the
world in 2011. Yoshinobu spoke
at the recent SAE Asian Steering
Committee Colloquia, which was
held during F+L Week (FLW) in
Singapore in March.
For motorcycles, tests were
conducted using various viscosity
grade oils. Yoshinobu presented
the results. SAE 5W-30 oils with an
HTHS viscosity of 2.7-2.9 caused
gear pitting during the tests. In
contrast, SAE 10W-30/40 and
20W-40 had no pitting, which were
measured using motorcycles from
four vendors. The current JASO
document specifies a minimum
HTHS of 2.9. Given the test results,
it may be difficult to lower viscosity
substantially in the upcoming
revision to JASO T903: 2011, he
said.
There may be a way out of the
box created by the need to boost fuel
economy without causing premature
component wear. TVS Motor’s
Kumar noted there’s another lever
that can be pushed to get the desired
results.
“Additives play a more
important role in controlling wear
than viscosity grades,” he said.
Indeed, it may be very difficult
to move viscosity grades at all,
at least for the current crop of
motorcycles. Yoshinobu presented
test results using higher and lower
viscosity grade lubricants than
recommended by motorcycle
makers. Dropping viscosity
decreases engine durability, increases
oil consumption and increases noise,
he said. A higher viscosity grade,
on the other hand, increases fuel
consumption, decreases drivability,
increases emissions and hinders low
temperature performance.
JASO is working to revise the
current motorcycle lube spec with
one change being the addition of
a gear-pitting test. According to
Yoshinobu, there are two reasons for
this. The first is the looming need to
go to lower-viscosity grades, which
may be necessary to achieve energy
savings. The second is that more
stringent emission requirements
are expected in the future, which
may mandate the use of low-
phosphorous lubricants.
Past development work on
a pitting test was done using a
machine designed for the standard
FZG gear wear test. However, there
was a lack of repeatability from lab
to lab and the test cost was too high,
USD900, per gear set. The industry,
therefore, is attempting to devise a
suitable alternate test. One candidate
is an inexpensive method based on
using a thrust needle bearing test
on a Unisteel machine. Yoshinobu
reported that correlation has
almost been achieved between this
approach and the FZG test.
The current goal is to complete
the revision of the standard by
March 2016. If the update happens
at any time during that year, the new
spec will become T903: 2016.
There is some concern that a
pitting test will not be ready in time,
however, said Ryan Welton, senior
market manager for the EMEA
region at additive maker Infineum.
Gear-pitting resistance is an
important parameter for dedicated
motorcycle oils, particularly if
viscosities are to be decreased.
“Gear-pitting requirements are one
of the biggest differences between
motorcycle and passenger car oils,”
Welton said.
Another important change
to the JASO standard has to do
with the friction test. Currently
this is supposed to be tested at
1,000 friction cycles, potentially
the equivalent of 700 kilometers
(km) of travel. But, drain intervals
average about 4,500 km. A test that
more closely resembles actual oil
change intervals would protect the
lube from degrading prematurely
between oil changes.
Coming up with a revised
standard that encompasses these
changes in time will be challenging.
Adding to the difficulty is a changing
global marketplace. In a presentation
at the UNITI Mineral Oil
Technology Congress in Stuttgart,
Germany in April, Welton noted that
some time ago Japanese motorcycle
makers dominated the market. As of
2011, the top two makers were still
Japanese, but the next two, with a
combined 25% market share, were
Indian – Hero and Bajaj.
The metallurgy of motorcycles
from India and China may differ
from Japan. These differences can
show up in gear pitting, an area
that an Infineum prototype product
addresses. The company is interested
in the motorcycle market, which is
growing at 7% a year. That growth
looks to continue as there currently
is only one motorcycle per 12 to 14
people in China and India, Welton
said. In contrast, for a more mature
market like Taiwan, the comparable
figure is one motorcycle per every
two people.
As for updates to the standard
governing motorcycle oils, these may
have to encompass the changing
world of two wheelers. Chinese and
Indian manufacturers are growing
in importance, and that could be
reflected in the hardware selected for
testing during the development of
the new specification.
With strong growth in two-
wheeler sales in China, India, Brazil
and elsewhere, the impact of a
revised JASO specification will be
felt worldwide as it is the de facto
global motorcycle industry oil
specification.
“Changes that are made to
improve the global JASO standard
will benefit riders and manufacturers
across the world through better
attributes of durability and rider
feel,” Welton said.
au t omo t i v e co l umn
The current motorcycle oil
specification is Japanese
Automobile Standards
Organization (JASO)
T903: 2011. JASOMB is
recommended for scooters.
