Bog or Not To Bog? Is QuickShot The Answer?
you have a liquid cooled Honda CRF you either suffer
from the "bog" or you know someone who does.
While the bog, off idle hesitation, seems to be more
pervasive on the CRF250X and CRF250R the big bore
thumpers aren't immune. California editions of the
CRF250X and CRF450X seem to suffer more than the standard
what actually causes the off-idle hesitation in the
first place? There's a lot of theories and I'm not
exactly sure which theory is correct. It's possible
the cause is a combination of several of the popular
theories. If you're interested in reading through
some of these theories do a search for "bog"
or "quickshot" in our CRF's Only message
board and you'll find lots of reading. Theories aside,
the bottom line is when the accelerator pump doesn't
deliver the correct amount of fuel quickly enough
off idle you'll experience the bog.
Boyesen, Inc.- www.boyesen.com
Included with excellent pictures
Weight: 0.4 oz.
Weight: 0.2 oz.
this problem is pervasive enough to have caught Boyesen's
attention and interest. They have developed what they
believe is the answer to this problem with their QuickShot
Accelerator Pump Cover. Essentially Boyesen's cover
replaces the stock cover. As you can see the covers
are very similar at first glance. However, a closer
look reveals the Boyesen's cover has two holes at
the top versus one hole just above center. Each as
a similar hole at center. One of the more common theories
on what the Boyesen QuickShot does has to do with
the two holes at the top. This theory suggests that
air gets trapped during normal operation. The stocker
doesn't have the ability to purge this trapped air.
The QuickShot, with the dual exit holes, purges the
trapped air and hence delivers a steady stream of
fuel right off idle. Forget all the theories. All
any of us care about is whether or not it works.
the cover could not be easier or quicker. Once you
get to the carb that is! The cover itself is held
in place by three phillips head screws. So, removing
the stock cover with the QuickShot is quick and easy.
The hard part is getting to the carb. Boyesen suggests
completely removing the carb. To speed installation,
I removed the sub-frame, shock, and the carb from
the intake manifold. This allowed me enough space
to access the pump cover.
you are working on your bike, especially when involving
the tank or carb, make sure you are in a well ventilated
area where there is the absence of any source of spark
or flame. In this case, make sure the petcock is off,
remove the fuel line and drain into an appropriate
container, and then drain the carb. When removing
the cover additional fuel will leak out. Be prepared
with an appropriate container to catch this fuel.
definitely increases responsiveness off-idle
quality construction and finish
are well written with excellent photos
removing the cover, I placed a shop towel below the
carb to catch any screws, spring, D-ring, O-ring,
or the diaphragm that might fall. Once the cover is
removed make sure you set aside the D-ring, O-ring,
diaphragm, and spring. Place the small D-ring in the
QuickShot cover with the flat side facing the cover.
This puts the round side facing the float bowl. Place
the O-ring in its place in the carb. There will likely
be some fuel still on the carb and this will help
hold the O-ring in place.
the diaphragm in the carb with the machined pin facing
the QuickShot cover. Place the spring in the center
of the cover and install the cover. DO NOT OVER TIGHTEN
THE SCREWS. The carb material is very soft and you
could easily strip the threads if you over tighten
so quick, we're not done yet. It's important to check
the timing screw for proper adjustment. Mine was spot
on but I've heard that others are set from the factory
incorrectly. In some cases, others have changed there's
in an attempt to chase away the bog. It's best to
remove the throttle pulley cover and check this with
the supplied tool.
the cover is installed and timing screw set correctly,
put the fuel line back on and test for fuel leaks.
If there are no leaks, proceed to finish installation
by putting the carb back on the intake manifold, install
the shock, sub-frame, and seat. Now the fun part,
had no problem starting the CRF450R. Three quick blips
of the throttle with the choke on and the motor came
to life as usual. Once it was properly warmed up,
I realized I had neglected to adjust my fuel screw
richer by 1/4 to 1/2 turn. Mine definitely needed
this adjustment. I went the full 1/2 out and that
smoothed out the idle and increased response off throttle.
up now I took it out for the first time. Even though
my '05 CRF450R didn't suffer from the bog, I immediately
noticed greater response and increased power off idle.
The CRF450R is not lacking in power. It's a wheelie
machine that eats rear tires for breakfast. Even still
the Boyesen Accelerator Pump Cover added to that power
and decrease hesitation while increasing the "grin
factor". I have to admit that I wasn't expecting
this much increase in performance and responsiveness
from this cover. I actually felt my bike was about
as good as it gets. I was pleasantly surprise to find
that was not the case.
wish we had a CRF in our stable that was suffering
from the bog to test how well this eliminates that
condition. Lacking that installing this on a well
jetted CRF450R, I was still very impressed with the
responsiveness and the added power down low. I came
into this review thinking there wasn't much room for
improvement. The Boyesen QuickShot proved me wrong.
Price may discourage some from buying and
hence not realizing the gains
hidden so no pit envy with this upgrade
by: CRF's Only Staff, May 2005
comments and questions to Reviews