New technology development for the fuel and lubricants in the automotive industry specifically motorcycle oil

1. BACKGROUND
Honda has been involved in environmental issues for
many years. Since the 1980's many environmental issues
have been highlighted that need to be dealt with on a global
basis. Fundamentally, they strive to deal with these issues
even before they are recognized as environmental issues. As
such, they have published a corporate objective to achieve a
30% CO2 emissions reduction as compared to 2000
emissions levels in all engines they produce by 2020.1
The motorcycle market has been continuously growing,
especially in Asia where 80% of the world's motorcycles are
sold. This further highlights the value of reducing CO2
emissions of motorcycles.
One way to reduce CO2 emissions is to improve fuel
efficiency. This strategy has been employed in the
automobile segment with design of lower friction engines and
more fuel efficient engine oils. Engine oil fuel efficiency can
be improved by reducing viscosity and formulating with low
friction chemistry.
2013-32-9063
20139063
Published 10/15/2013
Copyright @2013 SAE Japan and Copyright @ 2013 SAE International
doi:10.4271/2013-32-9063
saefuel.saejournals.org
Improving Fuel Efficiency of Motorcycle Oils
Brent Dohner, Alex Michlberger, and Chris Castanien
Lubrizol Corp.
Ananda Gajanayake
Lubrizol Japan Ltd.
Sumitaka Hirose
Honda R&D Co., Ltd.
ABSTRACT
As the motorcycle market grows, the fuel efficiency of motorcycle oils is becoming an important issue due to concerns
over the conservation of natural resources and the protection of the environment. Fuel efficient engine oils have been
developed for passenger cars by moving to lower viscosity grades and formulating the additive package to reduce friction.
Motorcycle oils, however, which operate in much higher temperature regimes, must also lubricate the transmission and the
clutch, and provide gear protection. This makes their requirements fundamentally very different from passenger car oils.
Developing fuel efficient motorcycle oils, therefore, can be a difficult challenge. Formulating to reduce friction may cause
clutch slippage and reducing the viscosity grade in motorcycles must be done carefully due to the need for gear protection.
Additionally, in high temperature motorcycle engines, low viscosity oils are more prone to oil consumption, which will
negatively impact fuel economy. They also may cause more deposit formation, which can reduce overall performance.
The lowest viscosity grade oil currently recommended by Honda for motorcycle applications is a 10W-30. This study
describes the development of a new 5W-30 motorcycle oil to deliver enhanced fuel efficiency in motorcycle engines. The
key target of this development was to deliver enhanced fuel efficiency with a 5W-30 while not compromising any of the
performance of the current high quality 10W-30 oil. Testing was conducted to validate oil consumption, clutch
performance, oxidation resistance, wear protection, gear protection, and engine cleanliness in modern Honda motorcycle
engines. In all aspects, the newly developed 5W-30 oil performed equivalent to or better than the high quality 10W-30
reference oil. As the final proof of performance, the new 5W-30 oil was compared with the 10W-30 reference oil in a
motored motorcycle engine friction torque test and clearly demonstrated the desired enhanced fuel efficiency.
CITATION: Dohner, B., Michlberger, A., Castanien, C., Gajanayake, A. et al., "Improving Fuel Efficiency of Motorcycle
Oils," SAE Int. J. Fuels Lubr. 6(3):2013, doi:10.4271/2013-32-9063.
____________________________________

2. Figure 1. 2020 Product CO2 Emissions Reduction
Targets
Figure 2. Growth in Asian Motorcycle Market2
While this strategy has been effective in the automotive
segment, it has limitations in the motorcycle segment.
Motorcycle oils operate in a much higher temperature regime
and must also lubricate the transmission and the clutch, and
provide gear protection. This makes their requirements
fundamentally very different from passenger car oils.
Developing fuel efficient motorcycle oils, therefore, can be a
difficult challenge.
OIL DEVELOPMENT
The objective of this oil development was to create the
most fuel efficient API SL / JASO MA2 quality low viscosity
motorcycle oil, that had all the performance qualities of a
current SAE 10W-30 oil. Two additional criteria were added
as new development targets for this oil. The oil was to be
formulated with a target 43 cSt kinematic viscosity at 40°C to
maximize fuel economy and the oil was also to be formulated
to a target of 12% NOACK to control oil volatility. Lower
viscosity improves fuel efficiency while lower volatility
enables the oil to maintain its fuel efficiency throughout use
in the engine.
As a result, an SAE 5W-30 oil was developed to meet
these criteria. The formulation shape and oil properties of this
oil are shown in table 1.
Table 1. Formulation and Properties
The oil was formulated with all Group III base oil to
optimize the viscometrics within the 5W-30 grade while
minimizing the volatility to ensure fuel economy durability.
In addition, a unique polymethacrylate (PMA) was used as a
viscosity modifier. It was chosen because PMA's are known
to improve fuel efficiency. In addition, this particular PMA
was chosen due to its shear stability. Utilizing a very shear
stable PMA enables formulating to lower viscosity without
the oil shearing out of grade. Finally, an additive approach
was developed to provide the enhanced durability needed for
a 5W-30 motorcycle oil in modern engines. In addition to
components present to meet the API SL performance level,
several motorcycle specific components were utilized such
as:
a. chemistry to enhance clutch performance and
minimize clutch slippage.
b. thermally stable detergent system designed for high
temperature motorcycle applications
c. gear protection components for gear pitting protection
in this low viscosity 5W-30
d. additional antioxidant chemistry for high temperature
conditions as well as to provide fuel economy durability by
preventing oxidative thickening
e. low volatility zinc dialkyl dithiophosphate to minimize
catalyst poisoning, hence further reducing emissions.
Dohner et al / SAE Int. J. Fuels Lubr. / Volume 6, Issue 3(November 2013)

3. This oil was then tested in a series of bench tests designed
to evaluate some basic properties such as corrosion protection
and deposit formation. In all cases, the oil performance was
outstanding.
Table 2. Bench Testing Results
Then the clutch friction performance was evaluated using
the JASO T903:2011 test procedure. The oil easily met the
criteria for JASO MA2, the highest JASO performance level
for a motorcycle oil.
Table 3. Clutch Testing Results
Since motorcycle engine oil is also lubricating the
transmission gear box, the low viscosity oil was also checked
for gear protection performance. The load carrying capacity
performance was evaluated using the ASTM D5182 (CEC
L-07-95) test procedure in a FZG test rig. The results in this
test show the 5W-30 candidate had equivalent performance
compared to the high quality 10W-30 reference oil.
Table 4. FZG Gear Test Results
Next, fatigue life performance was evaluated using a
needle roller bearing pitting test on a uni-steel bearing tester.
Thrust needle roller bearings are used to simulate gear fatigue
conditions due to their sliding operation
Figure 3. Weibull Probability Plot
In this test procedure, NSK FNTA2542 thrust needle
roller bearings with reduced rolling elements are set up in an
oil bath at 120°C to operate under maximum contact stress of
2.2 GPa and the peripheral speed of 2.6 m/s at the mid-point
of needle rollers. The occurrence of pitting on needle rollers
is detected using an accelerometer and the number of cycles
to fail is recorded. Pitting life is evaluated based on L10 and
L50 life indices derived by Weibull probability analysis on
multiple (N =6) test run data.
Figure 3 shows the Weibull probability plot comparing
failure probabilities of the candidate versus reference oils.
Accordingly, the candidate oil shows significantly better
fatigue life in L10 and equivalent fatigue life in L50. This
further supports equivalent gear pitting protection of the
candidate 5W-30 compared to the 10W-30 reference oil.
ENGINE TESTS
In addition to bench tests, four engine tests were used to
validate oil performance. In each engine test, a ‘reference’
test was conducted using the current high quality 10W-30 oil
to determine acceptable performance. Table 5 summarizes
each engine test.
Table 5. Test Engine Summary
Valvetrain Wear Testing
This test uses 110 cc air cooled engine (Engine 1) driven
by an electric motor. Engine speed is low to induce boundary
Dohner et al / SAE Int. J. Fuels Lubr. / Volume 6, Issue 3(November 2013)

4. lubrication and accelerate wear. The test is operated under a
proprietary procedure. All valvetrain parts including the
camshaft lobes, rocker arms, rocker arm pins, valve tips and
adjuster screws are carefully measured before and after the
test and compared to evaluate wear.
Figure 4. Valvetrain Wear Test Rig
Both reference and candidate oil tests showed only trace
wear, with many components having no measurable wear at
all. Each camshaft lobe was measured for maximum lobe
height (diameter) in three places as denoted in the figure 5.
Figure 5. Lobe Measurement Locations
Table 6. Camshaft Measurement Data
Viscosity Increase Testing
Like the valvetrain wear test, this test also uses the same
110 cc air cooled engine, but this engine is fired, and installed
on an engine dynamometer. The purpose of this test is to
determine the ability of the engine oil to resist viscosity
increase due to high temperature and high load operation.
During the evaluation, the engine is operated at wide open
throttle (WOT) and oil temperature is maintained at
approximately 145°C. The engine is operated at these harsh
conditions until the oil level drops to a predetermined level.
No additional oil is added during the test and oil samples are
taken every two hours and tested to determine viscosity.
Figure 6. Viscosity Increase Test Rig
Kinematic viscosity at 100°C for both the reference oil
and for the candidate oil, can be seen in figure 7. Clearly, the
candidate oil offers much more resistance to oxidative
thickening than the reference oil. The candidate oil also
showed lower oil consumption, as indicated by the longer test
duration.
Figure 7. Kinematic Viscosity at 100°C
In addition to viscosity measurements, elemental analysis
was conducted on each oil sample. From this analysis, %
Dohner et al / SAE Int. J. Fuels Lubr. / Volume 6, Issue 3(November 2013)

5. phosphorous retention was calculated. The candidate showed
much higher % phosphorous retention than the reference oil.3
Figure 8. Phosphorus Retention
Phosphorous retention is an important in order to maintain
wear protection. Also when phosphorous volatilizes and
leaves the engine, it can poison exhaust catalysts. When
exhaust catalysts become poisoned, the emissions increase.
While the objective of this development is improved fuel
efficiency, the ultimate goal is emissions reduction. Therefore
this oil may have additional emissions benefits beyond those
from the improved fuel economy.4,5
Transmission Gear Durability
Two different tests were used to evaluate the lubricant's
ability to protect transmission gears from wear (measured as
pitting). The first uses an air cooled single cylinder engine,
while the second uses a four cylinder liquid cooled engine.
These two engines are very different with regards to
architecture and operation, and thus place unique
requirements on engine oil.
The single cylinder engine is carbureted and utilizes a
single overhead camshaft with sliding contact rocker arms.
Rolling element bearings are used for the crankshaft,
camshaft, and transmission shafts. The four cylinder engine
employs fuel injection and other modern design elements
such as liquid cooling, journal bearings for the crankshaft and
camshafts, bucket and shim tappets, and lighter components.
All of these improvements optimize the engine for high speed
operation. By contrast, the design of the single cylinder
engine lends it to slower operation, but at higher
temperatures. The candidate oil must perform equally well in
both engine types.
Overall Performance Evaluation - Air
Cooled Engine
The 230 cc air cooled engine (Engine 2) was chosen for
overall performance evaluation. The engine was removed
from the motorcycle and installed in an engine test rig, and
operated under a proprietary procedure for a long duration at
high engine oil temperature.
All critical engine components were measured, weighed,
and inspected before and after the test with the emphasis on
transmission gear durability. To reduce variation, specially
made transmission gears were used for this test.
Transmission gear wear was evaluated by measuring and
summing the pitted area on each tooth of the mainshaft and
countershaft gears. The following tables show the total
amount of gear pitting for each set of mainshaft and
countershaft gears.
Table 7. Fifth Gear Pitted Area
This total pitted area represents only 4.9% and 5.2% of
the total gear tooth area for the reference and candidate tests,
respectively. Therefore, the 5W-30 candidate oil offers an
equivalent level of protection as the 10W-30 reference oil.
For the majority of the test, the engine is operated in 5th
gear, as a result, the pitting observed on the fourth gear set
was much lower, and can be seen in table 8.
Table 8. Fourth Gear Pitted Area
This total pitted area represents only 0.08% and 0.38% of
total tooth area for reference and candidate tests, respectively.
Pitting is low but present on both mainshaft and countershaft
gears which were operated with the reference lubricant.
Interestingly, the candidate gear set only exhibited pitting on
the mainshaft gear, with no pitting observed on the
countershaft gear. Additionally the majority of the pitting on
the mainshaft gear occurred only on one tooth.
Engine components were also evaluated for varnish and
carbon deposits. Components were rated in accordance with
ASTM rating scales and methods. In this scale, a rating of 10
represents a perfectly clean component. Table 9 summarizes
the deposit and varnish ratings.
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6. Table 9. Deposit and Varnish Ratings
The 5W-30 candidate oil has shown equivalent deposit
control when compared to the 10W-30 reference oil.
Overall Performance Evaluation - Liquid
Cooled Engine
The test engine chosen for the overall performance
evaluation was a 600cc four cylinder liquid cooled engine
(Engine 3). The engine was removed from the motorcycle
and installed in an engine test rig. The engine test was
conducted under proprietary conditions which are much more
severe than any normal drive cycle. In Figure 9, the test
engine can be seen operating at these test conditions, note the
extremely high exhaust temperatures which lead to glowing
red exhaust pipes.
Figure 9. Glowing Red Exhaust Pipes
Again, all critical engine components were measured
before and after the test to determine wear, and again,
emphasis was placed on transmission gear durability.
Table 10. Sixth Gear Pitted Area
Both reference and candidate oil protected the
transmission gears with very low amounts of pitting found on
the reference test and no instances of pitting observed on the
candidate test gears.
Table 11. Fifth Gear Pitted Area
Once again, the transmission gears experienced very low
levels of distress, with the candidate oil exhibiting no
instances of pitting. In addition to transmission gear wear
control, both the reference and the candidate oil exhibited
excellent wear protection on camshaft lobes, tappets,
bearings, and bushings throughout the engine.
Fuel Economy Evaluation
After demonstrating that the candidate oil could meet all
of the performance durability targets, it was necessary to
quantify its fuel economy benefit. To do this, a friction torque
testing (FTT) rig was developed. The rig uses an electric
motor to drive Engine 1. A high precision torque meter was
installed between the engine and motor to facilitate torque
measurement. The engine was driven to seven different
speeds (3,000 RPM to 9,000 RPM) and high speed torque
data was recorded at five oil sump temperatures (60°C, 80°C,
100°C, 120°C and 140°C) at each speed. This produced 35
unique operating conditions that were then analyzed for
reference and candidate oils. After each oil was tested, a high
detergent oil was used to thoroughly flush the engine before
the next test.
To increase the confidence in test results, repeat tests
were conducted for both reference and candidate oils and
statistical analysis was performed on the generated data. Out
of the 35 test conditions, the candidate significantly reduced
torque and power loss when compared to the reference in all
but two conditions.
The torque necessary to maintain engine rotation at each
condition set is a measure of the frictional losses within the
engine. The oil that exhibits the lower torque therefore offers
a fuel economy improvement.
Data can be analyzed and displayed in both empirical and
relative manners. Empirically, torque loss (or power loss if
respect is given to engine speed) can be plotted against
engine oil temperature for each engine speed, as shown in
figure 10.
Dohner et al / SAE Int. J. Fuels Lubr. / Volume 6, Issue 3(November 2013)

7. Figure 10. Average FTT Empirical Data
Data can also be analyzed in a relative sense by
comparing the candidate lubricants performance to that of the
reference oil. This is done by calculating the average friction
torque loss across each speed for both lubricants, then
determining the percentage difference between the two oils.
This analysis can be viewed in table 12.
Table 12. Average Friction Torque Loss Data
The candidate oil outperforms the reference oil across all
speeds and temperatures thus reducing torque loss by about
3%.
Due to typical operating conditions seen by single
cylinder air cooled engines, particular attention was given to
the oil sump temperatures of 120°C as the most critical
condition. Plots of relative friction torque reduction at various
speeds can be seen in figure 11.
Figure 11. Demonstration of Improved Fuel Efficiency
The candidate lubricant clearly offers reduced friction and
thus improved fuel efficiency when compared to the
reference.
SUMMARY
In keeping with the objective to reduce CO2 emissions, a
project was undertaken to develop a new oil to improve the
fuel efficiency of motorcycles. By consuming less fuel, the
emissions will be reduced.
The project was focused on developing a new low
viscosity, fuel efficient motorcycle oil, while matching or
exceeding the engine durability provided by a high quality
10W-30 motorcycle oil. As a result, an SAE 5W-30 oil was
developed to meet these criteria. This development utilized
Group III base oil, PMA viscosity modifier, and an additive
package specifically designed to deliver superior motorcycle
fuel economy.
Laboratory screen tests were initially used for oil
development. The oil developed was then evaluated in
modern motorcycle engine tests. These engine tests
demonstrated that engine durability was not compromised by
moving from a 10W-30 to this 5W-30 motorcycle oil.
Finally, friction torque testing clearly showed a friction
reduction, hence the fuel economy benefit of this new oil
which increased with lower engine temperature and higher
speed.
REFERENCES
1. http//world.honda.com/environmental/report/download/index1.html
2. Data provided by Honda from databases of JMVA: Japan Mini Vehicles
Association and AIRIA: Automobile Inspection & Registration
Information Association
3. Calculation of %P retention done in accordance with the ILSAC GF-5
specification.
4. Bardasz, E. A. Schiferl, E. Nahumck, W. Kelley, J. Williams, L. JSAE
20077288/SAE 2007-01-1990: “Low Volatility ZDDP Technology: Part
1 - Engines and Lubricant Performance in Field Applications”
5. Bardasz, E. A. Schiferl, E. Nahumck, W. Kelley, J. Williams, L. SAE
2007-01-4107: “Low Volatility ZDDP Technology: Part 2 - Exhaust
Catalysts Performance in Field Applications”
Dohner et al / SAE Int. J. Fuels Lubr. / Volume 6, Issue 3(November 2013)