Performance help - UPDATED(Solution found)

[KDXXXX]

Hi guys, new here and I'm really impressed by the knowledge pool.
I had a look around but can't seem to find something similar to my problem.
I'm having performance issues in low gears (i.e. 1st and 2nd)

Let me share with you the whole story:
Last week I collected my 2006 KDX 200 (my 1st 2t bike). I took off the fuel tank and cleaned it, I took out the carb and cleaned it. What it seemed like is that the bike wasn't ridden for a long time (sediment in the tank and carb) and that the previous owner used cheap 2t oil.

Bike's current state:
FMF Gnarly header and powercore 2 silencer
Airbox lid still in place
48 pilot jet, 160 main jet (Don't know the "clip" position )
Air screw 4 turns out
+/- 4400' altitude riding
Running 40:1 Bell Ray synthetic oil (Don't know which one)

I went for a ride Sunday and found that the bike has no power in 1st and most of 2nd gear. Only at the top of 2nd gear the powerband comes into play and in 3rd onward I'm happy with the power. Pulling away in 1st there is plenty of torque but as the revs pick up, the bike just doesn't produce power and most of 2nd gear.

The bike starts really easy but can't idle no matter what I do with the idling screw. (Incorrect pilot jet?)

What boggles my mind is that the engine performance/characteristics is so different between gears

What do you guys think is the problem, sticky power valve, jetting, ignorance?

Any advice welcome please.

[diymirage]

congrats on the new bike
the addition of a pipe is the best way to make power on a KDX so you should be on the right track

if im not mistaking you are running the stock jetting in your carb which is pig rich
the statement your idle screw is 4 turns out tells us your pilot jet is too rich

here is a good jetting guide

http://www.kdxrider.net/forums/viewtopi ... 105&t=1156

take an hour or so and properly jet the bike first, once that is done we can see if there is anything else that needs to be addressed but this is always the first step

[Julien D]

I would certainly check that the powervalves are operating properly and that compression is what it should be. Then move on to jetting, and then move on to modifications if needed.

[bufftester]

Yep, at 4 turns out your pilot is too rich, need to go smaller. Follow the jetting guide and you will be rewarded. Since it is a new to you bike a good inspection of all the bearings/seals/bushings would be good. If you don't have it yet, get a manual...and a torque wrench...your bike will thank you for it.

[adam728]

Should probably be more like a 42 on the pilot, or less, given your elevation.

[KarlP]

I went for a ride Sunday and found that the bike has no power in 1st and most of 2nd gear. Only at the top of 2nd gear the powerband comes into play and in 3rd onward I'm happy with the power. Pulling away in 1st there is plenty of torque but as the revs pick up, the bike just doesn't produce power and most of 2nd gear.

You may just not be used to the way it is putting power down. Most folks just use first to give the bike a shove from standstill. It almost sounds like what you are feeling is wheelspin in first and second. If your rear tire pressure is way high........

Take your time and sort out the basic stuff

[diymirage]

You may just not be used to the way it is putting power down. Most folks just use first to give the bike a shove from standstill. It almost sounds like what you are feeling is wheelspin in first and second. If your rear tire pressure is way high........

Take your time and sort out the basic stuff

lol, yeah on my KDXs 1st and 2nd gears are mighty dangerous and only used for wheel spin on dirt, even in 3rd and 4th all that is needed for a good wheelie is a crank of the throttle

[KDXXXX]

LOL I know the difference between wheel spin and an motor not performing as it should. I spent a total of 3 hours on the bike so its not as if I rode up and down the street.

I guess I'll have to bite the bullet this weekend and strip the KIPS and give it a good scrub.
Do I have to take out the piston in order to remove the entire powervalve system? If so, then I'll do the top end as well.

Should there be a gap between aftermarket reeds and the cage or should they fit snugly?

[diymirage]

no need to remove the piston to inspect the KIPS but you will need to take the cylinder off to get at everything
remember to support the actuator shaft and spin the nut clockwise to loosen it or you will break the shaft

reeds in their natural position should lay flush on the cage so if there is a gap on yours they are either faulty or installed wrong
definitely something to look into

if it were my bike I would:

1 fix the reeds
2 jet the bike because we KNOW it is off
3 then worry about things like KIPS or what not


in that order

[KDXXXX]

Thank for the advice guys. If you would guess, what jetting should I be running when I get new Boyesens reeds?

[ICRage42]

I had to jump up one for my boyesen power reeds. Prolly didn't need to jet different for it but made me feel better since I tore it apart.

[diymirage]

Thank for the advice guys. If you would guess, what jetting should I be running when I get new Boyesens reeds?

impossible to tell
there are too many variables, elevation, temperature, oil, gas quality, exhaust, reeds, what you had for breakfast that day

each bike needs to be properly jetted by going through the motions, there is no magic formula

[KDXXXX]

I have the solution to so many guy's problems.

This weekend I stuck gold!

The O-ring/gasket between the jet block and the carb was leaking. This meant that the bike was getting extra fuel the whole time and stuffed up the jetting.

If you have any problems remotely similar as what I had (I know there is a lot of you guys), check that your jet block gasket is 100% and follow the jetting guide and you'll be smiling all the way!

[diymirage]

good to hear

[Jaguar]

higher altitude means less oxygen and so the jetting has to be leaner to keep the ratio between fuel and oxygen the same.
the fuel bowl fuel level being too high made all the jetting too rich.
Solving that still leaves you needing to find the right lean jetting to match your altitude. Try as low as a 152 main.