Out with the old -
in with the new
As soon as we heard about
the new pumper-series carburetor from Edelbrock, we knew it was a
"must have" for our 400EX. The QwikSilver carb features an
adjustable accelerator pump that provides instant throttle
response, internal fuel cell and an anti-slosh plate to ensure
consistent fuel delivery. The easy tuneability will be much
appreciated when we make the next trip to the mountains, i.e. no
more jet changes!
Let's get started
 |
Strip it down! |
Make sure your fuel is off and then disconnect your battery. Now
remove your seat, front fender assembly and fuel tank. Remove the
throttle cables, airbox intake tube, and stock carburetor. *Pay
attention to the cable routing as you will want to route the new
cables the same as the stock ones. Next we installed a new
twist throttle and cable. The QwikSilver carburetor uses two cables
- a pull cable and a push cable. If you use a thumb throttle, it
will be necessary to grind away some of the throttle housing to
obtain full throttle.
 |
New twist throttle |
 |
Old twist throttle |
Remove the rubber aligment tabs
from the manifold. Trim the air intake tube you will be
re-installing. If you are running without an airbox lid, you
may want to plug the airbox and leave this off.
 |  |
Remove the rubber alignment tabs from
the manifold with a razor blade. |
Cut approx 1 1/2" off the air intake tube for cable
clearance. |
 |  |
Remove the pipe plug from the top of the
carburetor. |
QwikSilver with metering adjustment tool
installed. |
 |  |
View of metering adjustment tool from inside. |
A view of the top of the slide and the needle
adjuster. |
 |  |
Original carb - The butterfly causes airflow
turbulence, giving poor low-end. |
QwikSilver - At wide open, throttle airflow is only
restricted by a .125" needle. |
Install the QwikSilver carb into the manifold. Install the pull
cable and the idle cable on the cable wheel and adjust the cables
for 1/8" free-play in the throttle. Now align the carb vertically
and tighten the manifold clamp. Install your fuel tank and cut new
fuel line to the proper length. Re-install your plastic and any
other items that you removed and you are ready for a test ride.
How about some results?
Our 400EX
fired up immediately with no initial adjustments. We warmed her up
and headed for the QwikSilver chassis dyno. With the QwickSilver
carb installed, the dyno showed much more consistent power delivery
through-out the RPM range. The dyno showed that our HP had
increased from 29.3HP to 31.7HP. This was almost 2 1/2 HP over
stock but the expert R&D team felt the 400EX was running a
little lean at full throttle. A quick needle change to the 17e
would help this. With the 17 needle and the metering adjustment at
12 clicks from full rich, the R&D team was much happier with
the dyno reading, even though we showed a slight HP drop. We were
now showing the 400EX at 31HP. This is still a gain of 1 3/4 HP and
almost double the 1 HP gain from the exhaust system, K&N
filter, and removal of the airbox lid. Dollar for dollar, you
get more for your money with the QwikSilver carb than you do with
the typical exhaust kit.
Enough is enough, get it out
on the trail!
Throttle response is incredible. The
400EX starts easier and it pulls through the complete RPM
range. Since the QwikSilver carb is less affected by altitude
changes, it means no more jet changes next time we head to the
mountains.
If you own a 400EX, 300EX, Warrior, or
Bombardier DS650, you should put the QwikSilver at the top of your
list for performance modifications.
Special thanks to the
R&D crew at Edelbrock QwikSilver!
http://www.edelbrock.com/motorcycle QwikSilver
1320 Buena Vista Street
San Jacinto, CA 92583
Phone: 909-654-667
Tech line: 877-888-7504
