antistar
11-28-2010, 09:57 AM
I'm thinking on getting a HMF Competition slip-on.
HMF recommends: 165/170 Keihin Hex
Then I read on the HMF forum:
Main jet 152. Pilot jet 42.
fuel screw is 2.5 out.
****** NOTE: you MUST use the N424-26 series Pilot jet. (It is the smaller 23.5 millimeter version) NOT the more common 28 millimeter version.*********
Since the needle is not adjustable, use a .032 shim under the needle stop to richen the 1/4 to 3/4 if needed.
http://www.hmfracing.com/forums/showthread.php?t=4542
I went on to read other forums on the net and jetting seems to be all over the place.
I realize that there are many factors involved but I'm just looking for a good baseline.
I have a stock 2005 400ex.
Elevation around 800ft. (occasionally 2000 ft)
93 octane
Another question. This pipe has (3) different inserts. Would you have to rejet for running the different inserts?
Info on the pipe.
About the HMF Competition Series:The new HMF Competition Series exhaust was designed and tested for Sport ATVs and Dirtbikes. The Trimax Core technology features 3 levels of power and sound, allowing you to dictate the type of power and sound you need, when you need it. Included with every exhaust are 3 removable inserts, each of which effect the sound and power in different ways, giving the rider complete control.
Stage 1 uses an insert that restricts sound levels extensively yet produces industry leading power at that dB level.
Stage 2 uses a different sound altering insert that partially lowers sound levels without losing much horse power.
Stage 3 acts as an unrestricted core producing high dB levels with industry leading power throughout the RPM range.
Thanks
HMF recommends: 165/170 Keihin Hex
Then I read on the HMF forum:
Main jet 152. Pilot jet 42.
fuel screw is 2.5 out.
****** NOTE: you MUST use the N424-26 series Pilot jet. (It is the smaller 23.5 millimeter version) NOT the more common 28 millimeter version.*********
Since the needle is not adjustable, use a .032 shim under the needle stop to richen the 1/4 to 3/4 if needed.
http://www.hmfracing.com/forums/showthread.php?t=4542
I went on to read other forums on the net and jetting seems to be all over the place.
I realize that there are many factors involved but I'm just looking for a good baseline.
I have a stock 2005 400ex.
Elevation around 800ft. (occasionally 2000 ft)
93 octane
Another question. This pipe has (3) different inserts. Would you have to rejet for running the different inserts?
Info on the pipe.
About the HMF Competition Series:The new HMF Competition Series exhaust was designed and tested for Sport ATVs and Dirtbikes. The Trimax Core technology features 3 levels of power and sound, allowing you to dictate the type of power and sound you need, when you need it. Included with every exhaust are 3 removable inserts, each of which effect the sound and power in different ways, giving the rider complete control.
Stage 1 uses an insert that restricts sound levels extensively yet produces industry leading power at that dB level.
Stage 2 uses a different sound altering insert that partially lowers sound levels without losing much horse power.
Stage 3 acts as an unrestricted core producing high dB levels with industry leading power throughout the RPM range.
Thanks