Many thought that with the
introduction of newer and more fancy 4-Stroke quads from
Yamaha, Bombardier, and Honda, that the TRX 250R would
fall by the wayside. Quite the opposite has become true,
with companies doubling their efforts on making faster
and better engine kits for the 250R. As a 250R owner, I
keep close tabs on engine builders and what they are
doing, and one company that constantly comes up with
good reviews and comments is LRD
Performance Specialties , located in Gresham,
Oregon. LRD constantly improves and tests their setups
both on the track and on the dyno, always looking for
that sometimes small, but important, edge.
common setup on the stock OEM 250R cylinder is to
install the LA Sleeve 72mm big bore sleeve. This
actually equates to 293cc on the stock bore. LRD goes
one step further, installing a 227 Hardness sleeve,
milling and reshaping the stock head, and porting the
cylinder for your type of riding. They also machine
O-ring grooves into the cylinder for use with Viton
O-rings, which eliminates the need for a head gasket.
Leaky head gaskets are a common problem on the 295 kits,
and LRD does away with this, while also eliminating the
heat barrier caused by a head gasket.
The piston in this kit is a 72mm Wiseco 86' style
piston, used in conjunction with a custom spacer plate.
For those of you unfamiliar with a 250R engine, the 86'
style piston had the piston pin location 5mm lower than
the 87-89 piston. Hence, the rod on the 86' was shorter.
When using the 86' piston in the later year engines, the
use of a spacer plate is needed to prevent the piston
from slamming into the head. The piston gets a ceramic
coated crown and dry film coated skirts, which helps
reduce friction and keep temps down.
The porting chosen for this cylinder (generously
supplied by Janssen Racing)
was LRD's drag racing porting. The compression was setup
to use a 50/50 mix of AV Gas (100LL from your local
airport) and 93 octane pump gas. Upon kicking this motor
over, it seems to have a good 200-210 pounds of
Installation was a bit of a bear, due
to the OEM studs being frozen in the bottom end.
You need to take them out to install the longer studs
that are needed for the spacer plate. Installation of
the piston onto the rod was the same as putting any
other piston on..install the pin bearing,
piston, wrist pin, and circlips. Then the rings were
installed, some assembly oil was put onto the piston,
rings, and cylinder walls, and the cylinder was
installed and torqued to factory specifications. Then
the o rings were installed into the cylinder,
lubricated, and the head as slid onto the head studs.
Use of copper spacer washers is needed underneath the
OEM head nuts in order to prevent the nuts from
bottoming out on the stud, as the nuts have a closed
top. The nuts were then torqued to factory
specifications. All of the other components recommended
by LRD were then installed, which were a Boyesen Rad
Valve, LRD Team A/B Pipe, and a 39mm Keihin PWK.
After letting the silicone on the pipe
joints seal overnight, we poured in some AV Gas and
fired the motor up to do some break-in heat cycles.
Proper break in of a motor is a must. After a few heat
cycles, we took the motor for a few short rides, never
using more than half throttle. After about a tank and a
half of gas, the rings were well seated, and the piston
was ready for some serious action.
LRD recommended a 200 main jet due to
the cold weather here in Northern Minnesota. I decided
that was way too rich, and started with a 192 main, and
we eventually ended up at a 175 main to allow the motor
to fully rev on topend. After jetting the motor in, we
took the quad out for a quick acceleration run down a
deserted stretch of bare pavement. This thing hauls! While
being a drag racing ported cylinder, it had more than
ample low end, while really picking things up in the
mid-range and top end. I would have no qualms about
riding this motor on the trails, as it only has a slight
power loss off the very bottom of the powerband before
it hits in the midrange, and pulls all the way up to a
high revving topend. This motor has considerably more
power than my previous ported motor, plus the added
reliability of the O-ringed combustion chamber is a nice
thing to help ease the mind. The thing that impressed me
the most about this cylinder and kit is its wide, broad
powerband. It always seemed to have power on tap, with
no traction losing power hit or flat spots.
For those 250R owners that have been
thinking about getting a big bore motor, but don't want
to shell out all that extra cash for a Pro-X cylinder,
this 300 LRD kit is the one for you. Putting out about
the same power as a Pro-X 310 cylinder (again, a 293cc
on its stock bore) it offers far more performance per
dollar. With the O-ringed combustion chamber, all of the
problems associated with the big bore resleeves of the
stock cylinders are eliminated. This kit is a great way
to up the performance level, while still keeping that
stock sleeper-like look.
200 N.E. Victory Ave #A
Gresham, Oregon 97030