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document, please see our contact page. For information on our pledge to maintain your privacy click here. To learn more about
your friends at Top Gun Motorcycles, read about us here.
What's NEW!
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The roll-on test was just as revealing, and
possibly a little more fun. We were able to
find a stretch of 94 that was temporarily
devoid of other traffic, and led uphill for
approximately a mile. We started in 5th gear
at approximately 45 mph, and on signal –
whacked both throttles wide open. To make
things as even as possible, we matched our
body position as best as we could, with only a
slight lean forward (no tuck). I should mention
here that Elden’s 2005 is stock as far as
engine and exhaust systems are concerned,
with the exception of a Uni air filter and a half
turn on the pilot screw. I should also mention
that Elden doesn’t use a windscreen. The
2005 managed to pull away from the 2008
until my front tire was trying to stay even with
possibly a little more fun. We were able to
find a stretch of 94 that was temporarily
devoid of other traffic, and led uphill for
approximately a mile. We started in 5th gear
at approximately 45 mph, and on signal –
whacked both throttles wide open. To make
things as even as possible, we matched our
body position as best as we could, with only a
slight lean forward (no tuck). I should mention
here that Elden’s 2005 is stock as far as
engine and exhaust systems are concerned,
with the exception of a Uni air filter and a half
turn on the pilot screw. I should also mention
that Elden doesn’t use a windscreen. The
2005 managed to pull away from the 2008
until my front tire was trying to stay even with
his rear tire. We essentially stayed in that position all the way up the hill, and only during
the last 30 seconds or so was the 2008 able to chip away at the 05’s lead. Now, this may
not be the most scientific test of engine power, but it’s a darn good “real world” test of
engine power under common riding conditions. Ron (Jensen), hope that satisfies your
curiosity about the roll-on!
You’ve all seen pictures of the 2008. Sleek may not be the first word that comes to mind.
However, I would hope that Team Green’s engineers would have looked at the
aerodynamics of the fairing and come up with something that was “slick” in the air as well
as slick to the eye. The aerodynamic drag force on a motorcycle depends on three things:
the coefficient of drag (Cd - basically a measure of how aerodynamic the object is), the
frontal area, and velocity. This same principle was very familiar to us flying jets as well. All
of our ordnance, various pods and tanks, and suspension equipment was given a “drag
index” which allowed us to develop estimates of fuel consumption and impact on
performance. As they say, there are no free rides. We always had to balance our
performance and maneuverability requirements against the benefit received by hanging
something else under our wing. Here are some quick calculations. At 50mph, with a Cd = .7
and an estimated frontal area of 8.5 sq ft, you need to generate 5.1 hp just to overcome
the drag force. At 75 mph, that figure jumps to 17.1 hp. That’s not insignificant for a single
cylinder motorcycle with 38-40 hp at the wheel. I would say that the new KLR has an even
larger frontal area, but let’s be generous and only add one square foot to make the new
model 9.5 sq ft. Even better, let’s give the engineers the benefit of the doubt and reduce
the Cd to .6 (a 14% decrease). The figures for 50 mph and 75 mph are then 4.9 hp and
16.4 hp respectively. As you can see, even if you can streamline the motorcycle, increased
frontal area will undue a lot of the work you were trying to accomplish. This is kind of a long-
winded way to say that it really shouldn’t surprise us that the 2008 isn’t going to blow the
doors off the older model. And honestly, I’m not convinced the new fairing is more
aerodynamic, but we know it’s heavier, and we know the frontal area is larger, and that
takes more power.
Speaking of blowing the doors off, we were also riding with a DR650-mounted Rod Morris.
About 10 seconds after opening the throttles, Rod blew past us up the hill and never gave
back an inch. We were very surprised until we remembered that Rod is geared 15/45 on
his DR (stock is 15/42). That helped wipe the smile off his face a little (but not much), and it
is another great example of something we’ve been saying all along – if you want more
power out of your KLR or DR, try changing your gearing to match your riding conditions.
We really like 15/45 for the SoCal mountain roads. It’s a lot easier on your fuel
consumption than the usual routine of cutting up the airbox, and changing jetting and
exhaust.
In conclusion, it was interesting to see that at least in moderate temperatures, 75-82
degrees, the increased cooling capacity of the new model didn’t translate into cooler
engine temperatures. This isn’t a terrible indictment of the new model, but under these
riding conditions the new system isn’t reducing the thermal stress experienced by the
engine. It will be interesting to see the comparison in truly hot weather. Likewise, it was
interesting to see that the old model more than held its own during the roll-on comparison.
Don’t get us wrong, the 2008 is a nice handling street bike in its own right, but don’t start
writing the eulogy for the old models just yet. We still think that the old model is a superior
multisurface motorcycle in all regards. We have some projects in the works at Top Gun for
improving the older models (and we’re working on the 2008 as well) beyond the
performance of either factory variant. We’ll certainly keep you posted.
the last 30 seconds or so was the 2008 able to chip away at the 05’s lead. Now, this may
not be the most scientific test of engine power, but it’s a darn good “real world” test of
engine power under common riding conditions. Ron (Jensen), hope that satisfies your
curiosity about the roll-on!
You’ve all seen pictures of the 2008. Sleek may not be the first word that comes to mind.
However, I would hope that Team Green’s engineers would have looked at the
aerodynamics of the fairing and come up with something that was “slick” in the air as well
as slick to the eye. The aerodynamic drag force on a motorcycle depends on three things:
the coefficient of drag (Cd - basically a measure of how aerodynamic the object is), the
frontal area, and velocity. This same principle was very familiar to us flying jets as well. All
of our ordnance, various pods and tanks, and suspension equipment was given a “drag
index” which allowed us to develop estimates of fuel consumption and impact on
performance. As they say, there are no free rides. We always had to balance our
performance and maneuverability requirements against the benefit received by hanging
something else under our wing. Here are some quick calculations. At 50mph, with a Cd = .7
and an estimated frontal area of 8.5 sq ft, you need to generate 5.1 hp just to overcome
the drag force. At 75 mph, that figure jumps to 17.1 hp. That’s not insignificant for a single
cylinder motorcycle with 38-40 hp at the wheel. I would say that the new KLR has an even
larger frontal area, but let’s be generous and only add one square foot to make the new
model 9.5 sq ft. Even better, let’s give the engineers the benefit of the doubt and reduce
the Cd to .6 (a 14% decrease). The figures for 50 mph and 75 mph are then 4.9 hp and
16.4 hp respectively. As you can see, even if you can streamline the motorcycle, increased
frontal area will undue a lot of the work you were trying to accomplish. This is kind of a long-
winded way to say that it really shouldn’t surprise us that the 2008 isn’t going to blow the
doors off the older model. And honestly, I’m not convinced the new fairing is more
aerodynamic, but we know it’s heavier, and we know the frontal area is larger, and that
takes more power.
Speaking of blowing the doors off, we were also riding with a DR650-mounted Rod Morris.
About 10 seconds after opening the throttles, Rod blew past us up the hill and never gave
back an inch. We were very surprised until we remembered that Rod is geared 15/45 on
his DR (stock is 15/42). That helped wipe the smile off his face a little (but not much), and it
is another great example of something we’ve been saying all along – if you want more
power out of your KLR or DR, try changing your gearing to match your riding conditions.
We really like 15/45 for the SoCal mountain roads. It’s a lot easier on your fuel
consumption than the usual routine of cutting up the airbox, and changing jetting and
exhaust.
In conclusion, it was interesting to see that at least in moderate temperatures, 75-82
degrees, the increased cooling capacity of the new model didn’t translate into cooler
engine temperatures. This isn’t a terrible indictment of the new model, but under these
riding conditions the new system isn’t reducing the thermal stress experienced by the
engine. It will be interesting to see the comparison in truly hot weather. Likewise, it was
interesting to see that the old model more than held its own during the roll-on comparison.
Don’t get us wrong, the 2008 is a nice handling street bike in its own right, but don’t start
writing the eulogy for the old models just yet. We still think that the old model is a superior
multisurface motorcycle in all regards. We have some projects in the works at Top Gun for
improving the older models (and we’re working on the 2008 as well) beyond the
performance of either factory variant. We’ll certainly keep you posted.
| Checking the oil filter cover temperature on Elden's 2005 KLR-650. |
2008 KLR-650
by Todd Vosper
by Todd Vosper