Head mod jetting
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Head mod jetting
What is the general jetting recommendation for a RB mod head with a
stock carb? needle, MJ PJ clip?
92 KDX 200
FMF pipe
Boyesen reeds
92 pump gas
no air lid
Thanks
stock carb? needle, MJ PJ clip?
92 KDX 200
FMF pipe
Boyesen reeds
92 pump gas
no air lid
Thanks
- Indawoods
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There are so many starting points it's hard to name all of them. Normally start with what you have at hand. You have to get to a point.
What jets are in it now? Needle? Clip position?
What jets are in it now? Needle? Clip position?
*** Administrator //***
****'95 KDX 200/****
"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
****'95 KDX 200/****
"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
- Indawoods
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Wow... a perfect generic setup! That's rare and a great starting point.
If you read the jetting guide in the jetting section, then it will guide you through dialing in your new setup. The air screw will tell you allot and help dial in your new setup too, so don't overlook it.
http://kdxrider.net/forums/viewtopic.php?t=1156
If you don't have any spare brass right now... buy smaller than what you have in there right now. A CEL or DEL needle should work better in your carb too...
Play around with it... just don't go too extreme on changes without exploring the differences in between.
If you read the jetting guide in the jetting section, then it will guide you through dialing in your new setup. The air screw will tell you allot and help dial in your new setup too, so don't overlook it.
http://kdxrider.net/forums/viewtopic.php?t=1156
If you don't have any spare brass right now... buy smaller than what you have in there right now. A CEL or DEL needle should work better in your carb too...
Play around with it... just don't go too extreme on changes without exploring the differences in between.
*** Administrator //***
****'95 KDX 200/****
"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
****'95 KDX 200/****
"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
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- Indawoods
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- Location: Midwest
I would say around a 42-150 setup....
*** Administrator //***
****'95 KDX 200/****
"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
****'95 KDX 200/****
"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
- Indawoods
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- Location: Midwest
Always start in the middle position.
*** Administrator //***
****'95 KDX 200/****
"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
****'95 KDX 200/****
"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
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Does this sound right?
I was not able to get the air screw to make the bike rev higher, so I went
down on the pilot jet (45 to 40) but I got a bog when I crack the throttle hard so I lowered the clip on the needle ( from 3rd to 4th). It cleaned up a bit but not completely.
Any other suggestions?
92 KDX
Fatty Pipe
No air box cover
1172 needle
155 MJ
140 pilot
RB head
I was not able to get the air screw to make the bike rev higher, so I went
down on the pilot jet (45 to 40) but I got a bog when I crack the throttle hard so I lowered the clip on the needle ( from 3rd to 4th). It cleaned up a bit but not completely.
Any other suggestions?
92 KDX
Fatty Pipe
No air box cover
1172 needle
155 MJ
140 pilot
RB head
- Julien D
- KDXRider.net
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45 to 40 may have taken it too far. Try a 42, or run the airscrew in until the bog stops.
You want to set the airscrew for throttle response, not fastest idle. The fastest idle check is just to verify whether you have the correct pilot installed or not. Stock needle should have been r1173n as far as I know. I will reiterate, the CGK needle is recommended for 89-94 carbs. The needle jet is positioned differently in these carbs than the H series carbs.
CEL should work fine though.
You want to set the airscrew for throttle response, not fastest idle. The fastest idle check is just to verify whether you have the correct pilot installed or not. Stock needle should have been r1173n as far as I know. I will reiterate, the CGK needle is recommended for 89-94 carbs. The needle jet is positioned differently in these carbs than the H series carbs.
CEL should work fine though.
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- Julien D
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- kdxmaniac
- Supporting Member
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how does the head mod effect jetting? just curious... if you take compression, or add compression by reworking the head, how would the engine know any difference? just asking.
my bikes
-------------
96 ktm 300
96 XR400R
07 hayabusa
77 kz 1000
85 goldwing 1200
02 BIG DOG PITBULL
gone but not forgotten
96 kdx 200
98 ktm 380 "because it dang near killed me!"
97 ktm 360
96 ktm 250
93 wr 250
94 dr 350s
93 kx 250
07 gsxr 1000
99 bandit 1200
-------------
96 ktm 300
96 XR400R
07 hayabusa
77 kz 1000
85 goldwing 1200
02 BIG DOG PITBULL
gone but not forgotten
96 kdx 200
98 ktm 380 "because it dang near killed me!"
97 ktm 360
96 ktm 250
93 wr 250
94 dr 350s
93 kx 250
07 gsxr 1000
99 bandit 1200
- Julien D
- KDXRider.net
- Posts: 5858
- Joined: 07:53 pm Nov 07 2008
- Country: USA
- Contact:
- kdxmaniac
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uh, are you not compressing the air and fuel you have more? the head chamber size doesnt PULL more air in, that would come from porting you cylinder...... right??juliend wrote:Simply put; more or less air flow will require more or less fuel to match. Any change in compression is going to alter airflow characteristics.
Looks like I have ended up with 40 / 150 / CGK pos 3. I like it, a LOT.
my bikes
-------------
96 ktm 300
96 XR400R
07 hayabusa
77 kz 1000
85 goldwing 1200
02 BIG DOG PITBULL
gone but not forgotten
96 kdx 200
98 ktm 380 "because it dang near killed me!"
97 ktm 360
96 ktm 250
93 wr 250
94 dr 350s
93 kx 250
07 gsxr 1000
99 bandit 1200
-------------
96 ktm 300
96 XR400R
07 hayabusa
77 kz 1000
85 goldwing 1200
02 BIG DOG PITBULL
gone but not forgotten
96 kdx 200
98 ktm 380 "because it dang near killed me!"
97 ktm 360
96 ktm 250
93 wr 250
94 dr 350s
93 kx 250
07 gsxr 1000
99 bandit 1200
- Julien D
- KDXRider.net
- Posts: 5858
- Joined: 07:53 pm Nov 07 2008
- Country: USA
- Contact:
- kdxmaniac
- Supporting Member
- Posts: 595
- Joined: 09:01 pm May 24 2010
- Country:
there you go! you got it! compression has nothing to do with jeting! you are just compressing more of what you have... you may have to set your air screw, but that it. compression only adds bottom to mid......and trottle response, not a lick of topend.
my bikes
-------------
96 ktm 300
96 XR400R
07 hayabusa
77 kz 1000
85 goldwing 1200
02 BIG DOG PITBULL
gone but not forgotten
96 kdx 200
98 ktm 380 "because it dang near killed me!"
97 ktm 360
96 ktm 250
93 wr 250
94 dr 350s
93 kx 250
07 gsxr 1000
99 bandit 1200
-------------
96 ktm 300
96 XR400R
07 hayabusa
77 kz 1000
85 goldwing 1200
02 BIG DOG PITBULL
gone but not forgotten
96 kdx 200
98 ktm 380 "because it dang near killed me!"
97 ktm 360
96 ktm 250
93 wr 250
94 dr 350s
93 kx 250
07 gsxr 1000
99 bandit 1200