approved spark arrestors that are
removable for closed-course racing.
The kit comes with hardware to mount
the mufflers and springs to attach the
mid pipe and mufflers to the header.
This install was quite easy for a dual
muffler system. We took off the old
system, starting with removing the
muffler and then the stock header. You
use the stock header nuts to mount up
the new system.
Our first step in installing the Pro
Circuit system was to loosely mount
the header pipe (don’t tighten it
all the way down). Then we routed
and mounted the mid pipe that
connects to the header via a spring
and a mounting bracket that utilizes
a stock bolt and location. Next, we
removed two rear grab-bar bolts that
the mufflers utilize for mounts. We
connected the mufflers to the mid
pipe with the included springs and
mounted the mufflers in place with the
new hardware. Finally, we tightened
down the header once the rest of the
system was installed.
It is important to note that wrapping
the mid pipe in heat wrap can
decrease the heat exchange from
the muffler to the rear shock. Doing
this can decrease shock fade over
hours of hard riding. We didn’t notice
a huge difference in rear-suspension
performance, but the heat wrap will
help. We also installed a Dyno Jet
Power Commander V to adjust the
air to the fuel ratio through the EFI
system. It is always a good idea to
install a power programmer on a fuel-injection system when you purchase
an exhaust; otherwise, you could
potentially lose power. These are for
closed-course racing only.
More power is exactly what we
got through this Pro Circuit T- 6 dual
exhaust system! After adjusting our
PC V to accommodate the new system
and removing the Raptor’s airbox lid to
allow the engine to breathe deeper, the
Raptor flew out of its restricted shell.
Gains were made through the whole
power range, with the most noticeable
in the mid to top end. In stock trim,
the Yamaha was strong down low and
would fall on its face a little at the end
of the range, but not anymore.
The system was throaty-sounding
yet not too loud, so you didn’t feel the
need to wear earplugs after riding
it for a few hours like you would on
some other dual exhausts we have
tested. We haven’t got any complaints
with the performance of this full dual
exhaust system! Go to www.procircuit.
com or call (951) 738-8050 to order
your own system. ❏