Burson’s bike setup was
There are a couple of different ways the team achieves
this: Mapping is slightly altered on the bottom, with midrange and top-end settings left stock. A Rekluse TorqDrive
clutch is usually associated with hard-hitting Supercross
power, but it can be fine-tuned with different drive-spring
configurations for a desired clutch pull and power delivery. FMF’s complete Factory 4.1 titanium system is used,
providing more overall power with a spark-arrestor screen
installed, which not only tones down the power hit but also
brings the sound level down slightly.
Another external modification that Burson did to help
monitor power delivery was install a Motion Pro Rev2 throttle assembly. He felt that the FX throttle pull was too long
for it to completely open, forcing him to re-grip the throttle a
second time and pull longer to get it completely wide open.
The Rev2 throttle assembly has different-size reels that will
change how much twist is necessary for the throttle to completely open. Each kit has five different-size reels changing
the pull in about 10-degree increments and are color-coded
for easy identification. The larger the reel is, the shorter
the twist. Here is an example of how it works: if your stock
throttle has a 40mm reel and stock twist is 90 degrees (1/4
turn), the 45mm reel will reduce the twist to 80 degrees, the
50mm reel will reduce it to 70 degrees, while the 35mm reel
will increase the throttle twist to approximately 100 degrees.
Each kit comes complete with throttle cables, five different-size reels (one being stock), throttle housing and throttle
tube and grips. Burson uses the blue (40mm) reel, shortening the pull to around 10 degrees compared to stock.
With the YZ450FX having a wide-ratio transmission,
gearing has been a little tricky to figure out, so at the
moment the team is running really close to stock settings.
Burson admits he doesn’t use first very often, but when he
gets into nasty, tight sections, it works like a tractor, letting
him climb just about anything.
Just like the power delivery, Burson has the overall han-
dling on his Yamaha FX set for comfort over the long haul.
Most of the races he competes in throughout the year are
over two hours in length, and it’s no fun to be wrestling
around a 250-plus-pound unruly machine for that long.
Because he lives in the high desert of Southern California,
Nick says he sets all his bikes up to work in the valleys
and canyons of Lucerne. For him, if a bike works well out
there, it’s pretty much going to be good anywhere else, or
at least something you can dial in with clicker adjustments.
Purvines lets each rider work with their suspension
company of choice. Bob Bell and the crew at Precision
Concepts handle all the suspension duties for Burson. In
stock form, Nick felt the bike was a little too soft and busy,
blowing through the stroke on both ends at higher speeds.
Precision valved and sprung the bike with increased resistance to bottoming without taking away the plush overall
feel. This is done through lots of testing hours, as Bob Bell
explains: “It’s not an exact science, and every rider feels
things a little different. There is no substitute for testing
time, and the ultimate goal is making Nick comfortable so
he can have fun and win races.” Precision Concepts has
plenty of experience in testing, as they were a huge part of