Sackdx

Member
Sep 15, 2009
4
0
I have a new tome KDX project. I was working on jetting. The motor is fresh new reeds all stock. It runs very rich so I first checked the float level. Changed the pilot jet and I'm down to a 36 and the bike still runs rich. I think that is the smallest they go. The bike runs much better but the air screw is out three plus turns. My question is do PWK carbs wear out the needle jet/emulsion tube. Could I be getting some fuel from the main circuit? How much play should I have between the needle and the tube it slides in? Can this be replaced or is it time for a new carb?

Thank you for the help
Sacramento KDX
 

dansavage

Member
Jul 14, 2008
82
0
I think that you present a very unique question. I would think that given the composition differences between the needle jet and the emulsion tube, that the jet would show signs of wear first. That is just my hypothesis, of course.

How is your bike set up? Main jet size, what clip position is your needle jet in, is it stock or aftermarket?
 

domino dave

Member
Sep 24, 2003
136
0
Hi Sac - Not on my KDX, but on my sons XR, the float had a leak. There was a small amount of fuel in the float. Even though we set the float level, it was not closing when it should. Replaced the float and it ran fine. Probably not a real common problem, but one more thing to check. Dave
p.s. I also live in Sac. Like to ride Mammoth Bar and Forest Hill. Welcome to the site.
 

jonooffler

Member
Jun 10, 2009
77
0
Hi mate I have spent days or weeks trying to sort out my KDX220 it had a 42 pilot and ran very rich so went to a 38 better but still ran rich I ended up with a 35 and it still felt rich .However by this time I had lost all the punch from the motor and the air screw did nothing, so I went back to a 42 and left it at that it does run VERY rich to start but leans out at about 1/4 twist.I have been told they all run very rich unless your plug is fouling up I would try to ride it on a 42 and see how it goes.
Don't get into the idea of changing the oil gas mix I run 1-40 some riders said go to 1-50 all this does it make it run even richer.You could try 1-30.
Jono
 

Sackdx

Member
Sep 15, 2009
4
0
Thank you for posting help

For those who asked how the bike is setup, it is stock other than an FMF spark arrestor and a set of Boyesen 607 reeds. The main jet is new and 155 in size. The pilot jet is a 36 and the needle is stock. The motor was completely rebuilt last winter. The crank was rebuilt, new rod, piston and the cylinder was sleeved. I had a recommended local mechanic crank do the work and he used someone else for the machining.

The plan for tomorrow is to put my KDX220 carb on the 200 and see if that improves the situation. I know the 220 carb is smaller but I'm going to try it anyway. I will post the outcome later this weekend.

Domino Dave, I also ride in Forest Hill but have been spending more time in Georgetown. Less riders and new trails for me. Maybe we could get together sometime.

Thank you all for now.

SacKDX
 

Sackdx

Member
Sep 15, 2009
4
0
Update

I Tried the 220 carburetor this afternoon. The 200 runs worse using the 220’s carb. I should have guessed. I have not cleaned or set the float level. Does anyone else have any idea on why my KDX runs so rich. Could it be the choke circuit? What about the ignition?
 

domino dave

Member
Sep 24, 2003
136
0
Sackdx said:
My question is do PWK carbs wear out the needle jet/emulsion tube. Could I be getting some fuel from the main circuit? How much play should I have between the needle and the tube it slides in? Can this be replaced or is it time for a new carb?

Thank you for the help
Sacramento KDX
Getting back to your original question,"do they wear out?" I am curious if anybody knows the answer. I did have an old XR-80 many years ago that I was sure had a carb problem ... Finally got fed up with trying to fix it and bought a new carb. It ran fantastic. Sounds like maybe the road you are on. Do you know the history of your 200? A lot of hours etc.? We try to ride during weekdays to avoid the crowds. Dave
 

sr5bidder

Member
Oct 27, 2008
1,463
0
fresh motor.....did you break it in?
do you have the airbox lid on it?
is the filter clean?
is the silencer pluged up or clean?
are the power valves (kips) working properly?

the boysen instructions say that the reeds may cuase the Idle circuit to run a bit lean and the main to run a bit richer.

I would step away from the carb for a moment and check the above..

I suspect some people confuse lack of low end power for running rich...

you are warming the engine up all the way right? the sleeve and piston will run very crappy untill warmed up mine would smoke and bog really bad untill it got warmed then it was snappy happy from there on out
 
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