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still confused about jetting....
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Posted by: helibuf---------------------
i've read and re-read post on pipes and jetting. the way i read all these posts are once you put a aftermarket pipe on and do the air box mod the engine has more power and needs more fuel. which from reading these post's means i would need to richen the mixture accross the board.
based on what i'm reading as stock i have a for my 92 kdx 200:
1172n
150
48
these post and sites are recommending that i would use the following:
1173n
152 or 155
48
after looking at the sizes for these they seem smaller except for the change from the 150 to the 155.
so my ? is does this really indeed richen the mixture or is it leaning it do to the larger id of the needle?
here is a cut / past from just kdx.
Stock -Run the stock R1172N jet needle in the second from the top clip position, 48 pilot jet, 155 main jet and fine-tune the pilot circuit using the air screw.
With a performance pipe/expansion chamber, the air box lid removed and the stock or a performance silencer run a 45/48 pilot, R1173N jet needle in the mid clip position, a 152/155 main jet fine tune the pilot circuit using the air screw.
thanks for any help in clearing this up. i really don't want to blow an engine up. i'm just missing the point on how this richens the mixture.
thanks
doug
Posted by: Matt90GT---------------------
It doesnt. It leans it out. The stock KDX and KX bikes are jetting super rich. So you need to lean them out for top performance. IF you use the proper oil mixture, you will be fine on the motor.
Posted by: Jim Crenca---------------------
Remember that these jetting suggestions are just a guide and that each bike is different. My 94 with pipe and carb mod uses a CEJ needle with a 165 main and a 38 pilot. It runs great and is not rich nor does it have air leaks. Did you check the RB carb thread in the archive section? It will explain many findings of KDX users if you have the patience to read through it all!
Posted by: Dazza---------------------
I'm with you helibuf it is a bit confusing.
The Stock jets for E1 89 is 158m48p while the E2-E5 90-94 is 150m48p
They both use the same needle but in a different clip pos.
Quote:
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It doesnt. It leans it out. The stock KDX and KX bikes are jetting super rich
|
Everyone says they are rich and yes I agree with my E1 it now has a 155m and 45p.
Using the "start point" they say to run a 155main which is infact richer than the main in the E2-E5 bikes.
As Jim Crenca suggests it is a starting point and each bike should be checked
for a lean/rich condition.
Start rich and lean it out that way you have slight insurance from piston lock up.
Posted by: helibuf---------------------
well, i for one rather have it a bit richer and slightly sluggish then burn up. i've had my 92kdx 200 stock ever since day one. i usually ride at 3k-4k feet except once a year at 6k-8k feet. i have never had any reason to change it and its still on the same plug for the last 4 years. of course i finally just put the first rear tire on it since new so i don't ride much as you can see.
i thought i read though that when putting on a new pipe i would need to go richer on the mixture because of the extra power it now has, but it seems every one is still leaning them mixture out. thats where i'm getting this confusion from. i will do the plug tests in the mean time though. unfortantly buying needles get expensive<G>. oh well
Posted by: canyncarvr---------------------
Needles are only about $5 from sudco 800-998-3529. Yeah..S&H extra.
As long as it's jetted right, the fact that the numbers on the jets you use don't quite 'fit' with what everyone else 'says' don't matter a whit.
A sharply jetted bike is SUCH a blast to ride!! Much moh beddar than 'safe'.
have fun!!
Posted by: Jim Crenca---------------------
Doug,
Better yet, throw your bike in the truck and head to Jefferson, Oregon.
I know a guy there that loves to change brass and could probably jet your bike while listening to you blast through the gears over a cell phone. I hear he works cheap too :thumb:
Posted by: fuzzy---------------------
Quote:
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A sharply jetted bike is SUCH a blast to ride!! Much moh beddar than 'safe'
|
Speaking of which, I think a bike that is running spot-on is safer to ride. I've got to have that instant power to burp over things, etc.
You'll get the feel for how your bike is running the more you ride it, making jetting a much easier and less confusing task. These carbs are about the simplest 'induction device' you'll ever run accross. Practice makes perfect! :thumb:
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