May 15, 2003
New Speedometer Installation Footnote
Helical Performance System
left Sportster riders or Buellers out of our helical family of
V-twin close ratio performance systems. Johnson Engineering continues
to revolutionize the art of transmission technology with SportGear,
replacement assembly for 1991 and up Buell (tube frame trapdoor models
only) and Sportster five-speed transmissions. Our exciting new close
unites the proven characteristics of helical design with the power
and handling potential of unit construction v-twins. (more
Down For Top End Performance
steamroll the competition and enjoy a more comfortable ride while
doing it? SportGear’s the quickest way to unleash the full potential
of your Buell or Sportster, without sacrificing around town performance.
Designed specifically to improve all around performance for sport riders,
the computer generated helical tooth design delivers much quicker
than stock, something that will appeal especially to 883 riders.
do we do it? The cornerstone of the SportGear helical performance
system is our unitized 5th gear/countershaft combination.
Our 5th gear is a 22t helical that meshes seamlessly with our 42t
helical main gear, delivering an ouput ratio of 1.91:1, which is
nearly 14% more reduction than the stock ratio of 1.68:1. (XLs, at
10% reduction, similiar to our Big Twin TwistGear helical performance
cruising performance we recommend a 29/55 pulley setup
to lower engine speed
on those long interstate romps, while simultaneously delivering
the extra leg needed to let that engine wind out on the top
(The 29/55 swap is more for Buells and 1200s, although 883s might benefit
from a 55t rear pulley for lower rpm and still have acceptable acceleration.)
Result? Comfortable cruising with an appetite for the Autobahn.
chart above demonstrates the significant advantage SportGear
stock gearing throughout the shifting range. Take a look at that
top end, which is achieved with the final drive ratio indicated.
we compare a stock Buell drivetrain to a SportGear modification,
the recommended 29/55 pulley setup. The results are obvious; a near
identical overlay at shift points in 1st through 4th, meaning no
of acceleration, while top end at 7200 rpm improves dramatically over
the stock configuration (rev shift points in blue). For more info,
refer to our PDF SportGear
final drive remains 1:1, the advantage of SportGear technology comes
from applying the close ratio aspect of 1st through 4th combined
with the taller gearing required for top end improvement
with no loss of acceleration.
all the proven technology of TwistGear in an optimized sport performance
package, SportGear also includes our exclusive four-point caged ball
bearing, improved triple lip oil seal, and chamfered spacer improvements
long life and reliable operation.
Helical Close Ratio Technology
a 29/55 sprocket setup (recommended for all around performance), SportGear
delivers 13.6% more overall gear reduction than the stock 27/61 configuration.
Fifth gear revs are reduced over 16%, yet only a negligible 4.6% in
1st - 4th gears. The result is a taller overall gear ratio that still
retains near stock acceleration through the first four gears, and a
linear acceleration curve in fifth. It’s the same effect as an
overdrive, yet with all the benefits of a direct drive, and at a fraction
of the cost.
Comfortable Highway Cruising
With the recommended 29/55 sprocket setup, engine speed is reduced about
470 rpm at 60 mph in 5th gear while keeping the gear reduction in 1st-4th
gears close to original. This provides four narrow ratios for street
performance, with a highway cruising gear that delivers about 30 mph
more top end before hitting the rev limiter.
For Underpowered 883s
is the best improvement you can make for an economical, efficient solution
to quicker acceleration, a quick and elegant route to improving around
town riding and highway cruising at a fraction of the cost of adding
horsepower, especially with the recommended 27/55 pulley swap.
notice better comfort and performance immediately thanks to SportGear's
computer generated ratio reduction, which translates into closer gearing
and better pulling coming away from the light or manuvering through
Sealing Means No More Oiling
improvements include a lengthened main gear with
an integral retainer snap ring to keep the oil seal from falling
out of the bore (a common problem with OEM and other aftermarket
while also preventing the shell bearing from moving out of the bore.
Note also the beefier caged roller bearing at left, in place of
the drawn cup that comes stock. Much tougher, and also retained
by snap rings to keep everything neat and tidy.
addition, the trap door bearing retention screw on the counter shaft
(left side of illustration, below) has been strengthed to prevent
screw loosening. Torque it down, and
it stays tight! The engineering drawing below shows how our massive
improved fastener has the bite and the capacity for proper retention,
benefits include smoother shifting, a quieter transmission, less vibration
- especially with solid mount transmissions - and
cruising rpm, all in a super quick acceleration package especially
designed for the Harley sport rider. And with our superior oil
sealing and spacer technology, there's less down time for interval
maintainance, which means more riding without leaking.
Speedometer Installation Notes
present we're tooling a .086" spacer for the speedo pickup on
Sportsters and Buells equipped with electronic speedometers. In rare
cases, the end of the sensor may contact the main gear od, with obvious
results. Depending on your final ratios, you will probably need to
More Info In The Library
all this and more info, including OEM replacement part numbers, on your
own computer. Check out our new
SportGear PDF documents for download. Also check out our
SportGear Tables.pdf, for pulley P/Ns needed for a swap.
and TwistGear® are trademarks of Johnson Engineering, Inc. Buell™,
Dyna™, and Sportster™ are trademarks of the Harley-Davidson
Motor Company. No affiliation with the Harley-Davidson Motor Company
is implied or inferred.