Kx65 Pipe



YetiWoodz

Well-Known Member
Joined
Dec 19, 2019
Messages
878
I got some questions. Tuned pipes operate at a certain rpm band. How big of a band is it? 2000 rpm, 3000, 4000...etc? And what rpms does a kx65 operate at? I know its a pipe for torque, but....
 

Street Ryderz

Well-Known Member
Joined
Oct 14, 2016
Messages
3,723
I got some questions. Tuned pipes operate at a certain rpm band. How big of a band is it? 2000 rpm, 3000, 4000...etc? And what rpms does a kx65 operate at? I know its a pipe for torque, but....
Usually around 2000 for a dirtbike pipe and from 7-9k is normal,you can change this with length to suit you're port timing.
 

CrazyDan

Well-Known Member
Joined
Jul 9, 2016
Messages
3,054
To change where it hits you change header length. Longer for lower rpm, shorter for higher rpm. Changing intake manifold length has similar effects with where you get the highest torque.
 

YetiWoodz

Well-Known Member
Joined
Dec 19, 2019
Messages
878
Just curious, how does the diameter of the belly affect how the pipe works since the length is what affects port timing? Is it just to match engine displacement? Also, just got my pipe, is this dent gonna affect anything? I saw it before I bought it, I know I can get it out, but I'm probably not if its not gonna affect anything.
97858
 
Last edited:

YetiWoodz

Well-Known Member
Joined
Dec 19, 2019
Messages
878
I want my pipe to operate at around 4500-6500 rpm. How do I figure out how long to make the header pipe?
 

Street Ryderz

Well-Known Member
Joined
Oct 14, 2016
Messages
3,723
You need a total calculated length from piston face to 3/4 through the baffle cone(convergent) so say you have 160 exh duration x that by 1700 then divide by the peak 6500 = 41.8" total length,that's pretty low for a peak so the pipe is long (overall) and may stage earlier depending on type of pipe used.
 

YetiWoodz

Well-Known Member
Joined
Dec 19, 2019
Messages
878
Haven't heard from HP lately. Hasn't posted since June. Must've gotten lost in the desert chasing tumbleweeds on his bike or something :LOL:
 

YetiWoodz

Well-Known Member
Joined
Dec 19, 2019
Messages
878
I'm curious, what part of the expansion chamber determines the width of the powerband and why? My guess is baffle cone but not sure.
 
Last edited:
Top