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"XI" BOLT-ONS FROM R&D RACING PRODUCTS
 Within
the past few years R&D Racing has practically
taken the watercraft racing scene by storm. Just
in case you didn't know, they offer a line of
performance products, many of which are
currently being used by World and National title
champions such as, Minoru Kanamori, Christy
Carlson, Nicolas Rius, Victor Sheldon, Chris
Fischetti and many others.
Although racing is the ultimate proving ground
for product development, owners Glenn Dickinson
and Bill Chapin believe that their products
should perform flawlessly, both on and off the
track. This brings us to our main storyline. R&D
Racing has developed a bolt-on performance kit
for the popular Kawasaki 750 XI. R&D's "XI"
package was created to meet the needs of the
recreational enthusiast. The end results will
impress you, so get comfortable and read all
about it!
JUST THE FACTS
 Many
sit-down watercraft owners have one time or
another thought to themselves, wow if I just had
a little more power, that would be great! Yet,
in reality you feel that messing with the
factory setup will only decrease reliability.
This may be true in some extreme cases, but
today's watercraft are manufactured with such
high standards and strong engine components,
that slightly modifying your PWC usually won't
hurt a thing. In fact, (most cases) the owner
can really benefit from a well-designed
performance package.
 Now,
another point to consider is that most sit-down
owners have a wide variety of people sharing
their units, moms and dads, children, friends,
etc. With this wide range of rider styles and
abilities comes the need for total reliability
and safety. The bottom line here is, that nobody
wants to be stranded in the middle of nowhere or
left sitting on the shore with a broken-down
watercraft. This sport is supposed to be fun,
right? Since the key here is longevity, the
performance parts you choose should be well
thought out, tested and manufactured by a
reputable company. R&D Racing manufactures the
perfect example of a well-rounded performance
package. The package we are going to test is
designed to raise the overall horsepower, speed
and handling of your "XI." Along with
reliability, convenience is also a big factor.
Since many sit-down owners enjoy the simplicity
of their oil-injector system, R&D claims their
"XI" package can be used with or without the
injector system. The type of gasoline also must
be taken into consideration. Since all Kawasaki
"XI" models come with a fairly conservative
compression ratio, raising the level will always
improve engine performance. But, let's be
realistic, for general recreation no one wants
to run racing fuel in their watercraft! For
racing purposes it’s necessary, for recreation
it's ridiculous! The rule of thumb, is to keep
the compression around #175 PSI. This is the
ideal/maximum ratio for 92 octane pump gas. This
way gasoline will never be an inconvenience or a
budget factor. It's also better for long term
engine life.
FOR STARTERS
 Since
the release of the Kawasaki "XI" it has
mechanically remained the same. It comes
equipped with a twin carb, (40 mm Keihin) reed
induction, 750 cc engine. Stock compression is
approximately #150 cranking PSI. Engine
lubrication is handled by direct manifold
injection. Kawasaki uses a single stage, axial
flow pump with a stainless steel, five-blade
impeller. Note: For this particular test we are
not going to change the impeller.
The top-speed of a stock "XI" is 46.5 to 47
mph. At full speed the rpm is about 6200.
Another test that I perform is the 100-yard
dash. This acceleration test starts from a
standing idle, then I grab
full throttle, run out 300 feet and record the
time length. Our test "XI" came in at 6.53 to
6.60 seconds. Now with all the basic OEM data
recorded, it was time to put the R&D Racing
technicians to work. Bill Chapin and Glenn
Dickinson were on hand to install their
hardgoods. Now, keep in mind that the R&D
package can be installed with general hand
tools. The hardest part will be setting your
carburetors pop-off pressure. But, don't panic,
any reputable shop or person should be able to
handle it for you. To begin with Chapin removed
the carbs and manifold. The front covers were
removed to expose the low, mid and high-speed
jets, plus the needle/seat assembly. R&D
recommends increasing the mid-jet from a #78, to
a #82. The low and high-speed jets remained the
same and are well suited for their application.
Next the pop-off pressure was lowered to #17
pounds. This will ensure proper fuel delivery,
at all rpm ranges. With the carbs properly set
up, a pair of R&D "Reed Stuffers" were
installed. These specially-molded pieces fit
directly into the OEM reed cage and help
increase air speed through the reed valve
assembly. Having greater air
 velocity
really improves throttle response, especially at
the bottom-end range. The carburetors were
reinstalled and the stock flame arrestor was
eliminated. Note: For the test we used an R&D
Pro-Flow Power Plenum air filter.
While the final touches were being done to the
induction system, Glenn was installing an R&D
timing advance plate. This trick little item
advances the 750's timing from 16 degrees to a
full 23 degrees. This part really helps improve
low/mid-range performance. Next came the new R&D
cylinder head, its specially designed combustion
chamber raises the compression, about 25 pounds
over stock. Perfectly suited for 92 octane pump
gas. Instead of a head gasket, R&D prefers using
high-temp O-Rings for sealing. Their head also
has an improved water-jacket design for better
waterflow and cooling capabilities.
With all the basic engine bolt-ons completed,
the final engine component was the exhaust
system.
R&D's exhaust system works in conjunction with
the stock headpipe and waterbox. Since the R&D
system uses the OEM waterbox, the change in
sound level is virtually undetectable. No other
modifications to the exhaust system were
performed. The entire R&D exhaust takes about 20
minutes to install.
The final
 step
to the R&D Racing "XI" package was in the pump
department. To help reduce cavitation in the
turns and rougher water conditions, an exclusive
R&D Racing "Aquavein" intake grate was
installed. Their patented wing concept instantly
improves pump efficiency, by keeping the pump
loaded-up better. Keeping the pump loaded also
improves the craft's top-speed. Since our test
craft will be traveling much faster across the
water, handling and stability is crucial. For
added control, the stock ride plate was replaced
with an R&D " speed plate." With the R&D "XI"
package completed, we were ready to test it
against our stock vehicle.
THE BIG PICTURE
Bill Chapin took the "XI" out for a quick
warm-up run and a spark plug check. He then made
his final adjustment to the high and low-speed
needles (1 3/4 on the low and 5/8 on the high).
Completely satisfied with the XI's newfound
power, it was time to get some serious radar
numbers. The first speed pass was incredible,
the R&D "XI" broke into the mid-51’s! That was a
rocksolid 4.5 mph faster than stock. Bill made a
few more passes and our trusty "Stalker" radar
guns revealed consistent mid to upper-51’s.
Note: See sidebar for complete details.
We also recorded the increase in rpms. Our
new "XI" pushed the tachometer to 6710 rpm. A
500 rpm
increase over stock, means one thing, a big gain
in overall horsepower! To further prove these
results I performed my standard 100 yard
acceleration dash. The elapsed time dropped a
full second, from 6.6 to 5.5 seconds. What I
like about this particular test, is that it
really demonstrates the dramatic increase in
bottom and mid-range power. Having greater
low/mid-end power at your fingertips can be very
useful, especially when you've got two people on
board.
Well, now you know, when you outline a
well-rounded package with all the right
ingredients, the results can be very rewarding.
Perhaps the best part about this package is that
anyone can install the entire setup by
themselves. Everything bolts into place, with no
other special modifications needed. Bill Chapin
made an interesting point to me. He said that
many people who already own a sit-down craft or
maybe even a pair of them, cannot afford to go
out and purchase one of the new style
big-dollar, high-performance models. So, the
beauty about our performance package is that
it's cost effective and the performance results
are worth every penny. In addition, his/her
watercraft will perform as well as some of the
new expensive machines, plus it's totally
reliable!
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