WE RIDE of the seat down. Phil also changed to 20mm outset triple clamps to get more traction on the front wheel. With a plethora of factory parts covering the bike, we were mostly intrigued by two things. The first one was a wire that went into the airbox. We asked Phil’s mechanic,
Isaiah Murphy, what the wire led to. We were surprised
by his answer. The wire leads to a battery in the airbox.
This battery powers the GET data system and its sensors.
It turns out that the data system needed more juice than
the magneto could generate. It is a small 4-cell battery
like the ones used on RC cars. Next, we noticed that Phil’s
Suzuki RM-Z250 was running something that we find on
lots of Honda, Yamaha, Suzuki and Kawasaki Pro bikes—a
KTM throttle body. Isaiah smiled and moved on to something else when we pointed it out. But, it is no secret that
the location of the KTM’s throttle-body injector nozzle,
which is the opposite of the nozzles on Japanese models,
mists the fuel more efficiently. We see this throttle body
on a large number of factory bikes.
The setup of Phil’s bike is pretty basic. The levers are
set in a neutral position, with the front brake lever a little
lower than the clutch (even though Phil feels that they are
level with each other). Phil runs his rear brake pedal on
the low side for a Pro rider. Why? He says he has a tendency to ride the rear brake pedal if it’s high. Conversely,
he runs the shifter one notch higher than normal but has
a fatter shifter tip for an improved feel.
We spent all of our time on Phil’s JGRMX Suzuki
RM-Z250 on JGRMX’s Supercross test track. The first
thing we noticed was the change in ergonomics. The
small changes Phil made really allowed our test riders
to feel at home, especially our bigger riders, as the taller
front and lower rear made the cockpit feel larger. The
engine was potent out of the corners and didn’t require
much in the way of clutch help. The power changes were
interesting, as the RM-Z250 delivered a 450 style of power.
We could almost lug the bike around the corners, although
we felt a little hampered by the lack of over-rev. The short
top end meant that riders couldn’t be lazy and just wind
it out on top; they had to short-shift. On a side note: Kyle
Peters, who was the replacement rider for Matt Bisceglia
before he was replaced by Kyle Cunningham, was at the
JGR test track when we were there, and he had a different engine that had a longer over-rev.
The JGR RM-Z250 felt light and nimble on the track,
which is something that even the heavy stocker is capable of. We struggled a little with oversteer that knifed the
front end on occasion due to the 20mm offset (stock is
22mm); however, the faster we rode, the better the front
end tracked. Of course, the suspension was on the stiff
side. This is normal with the Supercross bikes of Pro riders, because they ride Supercross every day of the week
and go a little stiffer all the time. The shock had a classic
Supercross dead-feeling that gave our riders confidence
that the rear end wasn’t going to come up unexpectedly.
The forks were stiff but had some plushness at the top
to absorb some of the small chop that Supercross tracks
develop. The front brake was amazingly strong but had a
graduated feel that made it easy to modulate.
Make no mistake about it; JGR has a potent Suzuki
RM-Z250—and they managed to build it in an amazingly
short period of time after their last-minute departure from
the Yamaha fold. It was surprising how fully the bike was
developed, especially given that Suzuki had very little
RM-Z250 race data from the last seven years to share with
JGR. More significant is that the JGR effort might breathe
life into Suzuki’s moribund RM-Z250 production program.
A motivated Suzuki has been a powerhouse in the past,
so we are excited to see what the collaborative efforts of
Suzuki and JGRMX bring in the years to come. ❏
The GET device is now located on the front fender so the
rider can see the 1-10 LED display.
RM-Z250 throttle body, right? Take a closer look. It is a KTM
throttle body. Many teams are using them this season.
JGRMX took a back seat on the RM-Z250 engine and suspension development. It came straight from Japan.