Fuel For Thought
by Rod Morris
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Welcome To Fuel For Thought
Written by: Rod Morris
Glossary of terms and abbreviations:
MSM - Multisurface Motorcycles/Motorcyclist
MMP - Multisurface Motorcycle Products
TGMP - Top Gun Motorcycle Products
MSM Weight Classifications:
Lightweight (LW) - up to 250lbs
Middleweight (MW) - 251lbs - 300lbs
Light-Heavyweight (LHW) - 301lbs - 350lbs
Heavyweight (HW) - 351lbs - 400lbs
WHICH OIL TO USE
The question of which oil to use in a motorcycle has been discussed and cussed for as
long as I can remember and still doesn't have a definitive answer. Deciding on which
type of oil to use is like picking out your clothes, what beer to drink, and the list goes
on. You buy what you like.
As you may already know, oil choice is highly personal and riders can be fierce in the
defense of their favorite formulation. Recent comments on our website were made in
context of people blindly relying on the Internet without knowing where the information
is coming from or who is providing it more than an indictment of a particular oil, but it
did elicit some reader questions. We use and recommend motorcycle-specific oil for
two reasons. First, we are making recommendations for our customers and readers
and they don't all ride the same motorcycle, nor in the same conditions. Case in point,
the owner's manual for the very popular Yamaha WR250R specifically notes to NOT
use diesel grade oils. Additionally, we don't have time to run every formulation or brand
of oil on our bikes for evaluation. Second, we have developed a network of experts
from all aspects of motorcycling and we've been lucky enough to learn from all of them.
This includes experts in the oil industry, race engine builders, aftermarket parts
developers, etc. The advice has always been the same - use motorcycle-sprcific oil.
We've never claimed to be experts in the field of rating oils, but we do claim to be
informed by experts.
A Shell Oil rep was contacted about Rotella use in motorcycles. Bottom line, they don't
market it for motorcycles but if an engine doesn't specify a gasoline spec higher than
SM and viscosity of Rotella is the same as OEM, the rep saw no problem. Shell did say
that it is not a motorcycle-specific oil and that their motorcycle-specific oils (not
generally found in the U.S.) have additive packages that differ from regular Rotella.
Shell said the JASO ratings itself is no guarantee that the oil is optimally formulated for
a motorcycle, only that it should be compatible with a wet clutch. Rotella does have
more additives than automotive oil so that helps.
Maxima Oil was contacted and they were much less flattering about Rotella's abilities
as a motorcycle oil. As soon as we have more Maxima info we'll include that in a future
Bottom line, if you like Rotella and it meets the engine specs, use it. For our purposes,
we'll continue to recommend motorcycle-specific oils for the same reasons the Shell
rep pointed out - additive packages are specifically designed for motorcycle engines.
Also remember that most motorcycles have an integrated transmission that uses the
engine oil for lubrication. Transmissions create very high pressures called shearing
forces and that's why there are more and better additives in motorcycle-specific oils.
If the oil you use now is working well for you, that's great. Go with the oil you feel
comfortable with; that way you'll never second-guess yourself and you can spend your
time enjoying your motorcycle. We're only passing on information we've collected from
A few oil facts from the experts:
Car oils are mandated by the EPA to contain zinc and phosphates. Car oil contains a
500 parts per million rating.
Car oil is also mandated to have OCP Polymers. Car oil uses Group 2 base stock
which is the lowest rating.
Motorcycle oils are also mandated by the EPA to contain zinc and phosphates.
Motorcycle oil contains a 2000 parts per million rating (4 times higher than car oil).
Motorcycle oil is mandated to have OCP Polymers. Motorcycle oil uses Group 5 base
stock which is the highest rating.
BIG SINGLE GEARING
This is another highly contested area in motorcycling, but again, we've consulted
experts in this field before using or recommending which combination to use on a big
single like the KLR650 and DR650. The experts convinced us long ago to never gear a
big single higher (larger front sprocket, smaller rear or both). Notice I keep saying, "big
single"; that's what makes higher gearing different than on a V-Twin or Inline Four.
A four stroke is a four stroke because the piston or pistons make four strokes to
complete a cycle which takes two complete revolutions (720 degrees). Only one of
those strokes is the “power” stroke. That works OK in multi-cylinder engines because
the other cylinders are firing which keeps momentum moving. A big single engine is
losing momentum (power) through most of the cycle. To make matters worse in the
KLR, you have a 100mm cylinder with only one spark plug trying to keep a rather large
piston moving. The DR fares a bit better because it uses two spark plugs which can
help make more efficient use of the fuel/air mixture.
How does all this relate to gearing? We've weighed several KLRs on commercial
scales, in stock condition with full gas tanks. The "A" model came in around 413lbs.
The "E" model came in about 428lbs (lots of heavy bracing for that very nice fairing).
An independent tester had done a dyno check on both the "A" and "E" models and
found that the "A" model had 37.7HP and the "E" model had 34.8HP. We think the
difference is because the "E" model has a catalytic converter in the front part of the
muffler (check your manual).
Add a rider, heavy boxes that stick out in wind, a tail bag or box, tall wind shield
catching more air and you now have one big load to push down the road and what
about long grades (unless you go downhill both ways). As careful as many riders think
they are, they still let the RPMS get too low before shifting and the engine lugs. We've
all done it. Lugging a KLR engine is a sure fire way to cause damage. It's very hard
on the valves, piston rings and doohickey system, even with just a rider and no extra
weight. With a lot of extra weight the damage ratio goes up even quicker. This all
happens with stock gearing. Add a higher gear ratio and any lugging occurs much
Moving on to the better gas mileage theory with higher gearing. Unless you never get
off the freeway and drive 80MPH everywhere you go, it's possible that you might get a
little better mileage but at a different price. The KLR engine was never designed to ride
at much more than 5500RPMs for sustained periods like constant freeway riding. If
that's what you want to do, we suggest getting a 650 V-Strom or some other bike better
designed for that. We've proven more than once that gas mileage has actually gone up
when we gear lower and goes down with higher gearing. Going back to the 4-stroke
loss of power, the tendency is to just twist the throttle more to speed up. You have to
turn the throttle farther to get going, thus dumping more gas into that 100mm hole; but
with lower gearing you turn the throttle less, the engine is turning at a more safe RPM
resulting in less gas going in. This goes for the DR also. It has higher transmission
ratios; in fact I found that I tended to lug the DR quicker than the KLR, but the DR is
lighter and has two spark plugs, so it all evens out.
Big boring either bike is not a good idea. Big singles weren't designed to hop-up. Yes,
it has been done, but again, our experts say it's not a good idea. Besides possible
engine, balancer system, and other failure you must use premium fuel, risk heating
problems from thinner cylinders and other components. We leave big singles in stock
form. No ill fitting, loud exhaust systems, no carb jetting, no air box cutting - nothing.
That's why they make Sport Bikes, Tourers and even Harleys.
We get a consistent 50-55 MPG on the KLR with lower gearing, 55-60 on the DR.
(Todd's note – this obviously varies with the rider and riding speed. I spend more time
on the freeway at higher speed than Rod or Elden and I have a tall sitting height (more
drag) - my mileage is generally at the lower end of the range compared to them. Your
situation is likely different as well, and will affect your results.)
These are some different ratios to help clear up what happens:
15/43 Stock - 2.90
15/44 - 2.93 good street only
15/45 - 3.00 good street or off-road
15.46 - 3.06 good trail
15/47 - 3.13 good two-up off-road
15/42 Stock - 2.80
14/42 - 3.00 good street only
14/43 - 3.07 good street or off-road
We found that a 3.00 ratio is a very good all around combo to use for the KLR unless
you drive lots of freeway. The DR works well on the freeway with 3.00 because of the
Now, make yourself happy and do whatever you're comfortable with.