Carb adjust-o-rama

mnnthbx · Mar 6, 2004

I've got my bike running well, but during the warmer weather, it is starting to feel a little flat till the RPMs build if I dog it at low speed. I have no place to do a plug chop, so I'm forced to work around that method.

The bike is a 03 200. FMF woods, silencer, DF2, air box lid, 42 pilot, 155 main, 1173K mid clip, AS 1.5.

Months ago when I put the 42 pilot in it helped tons. So I'm confident with that jet.

Things of note: ***The "soft" bottom, is noticed when I'm at walking speed in 2nd, and quickly open the throttle to full open. ***If I slowly roll on the throttle, it feels a bit rough coming off the pilot (1/4-1/3 open at throttle). A bit of duh-dadah-daduh roughness. ***The silencer always has thin black spooge splattered around the outlet, and usually on the rear fender and my back. (Could be the FMF silencer turned up more?) The bike always starts very easy, and never seems "too" smoky. ***I live in Knoxville, not sure the alt., somewhere around 1000ft. & more heading into the mountains.

Should I (A) start by dropping the needle a clip, or (B) putting a 152 main in.

The rough, off pilot transition makes me think the needle is rich, and the spooge makes me think the main is rich. But as always, I'm cautious not to get too lean. I have searched till I'm crosseyed, and I know this board is full of this same question 10,000 times over, but I value your thoughts on this specific situation. As always, thanks for your help. Greg.

Mac · Mar 6, 2004

It does sound like your too rich in the pilot area. If dropping the needle doesn't help try playing with the a/f screw. If it runs better @ 2-3 turns out then you need a smaller pilot.

Your mainjet doesn't contribute much to off idle response. Tweek that with "seat of pants" or plugchops.

mnnthbx · Mar 6, 2004

Thanks. I think the pilot is fine. While the this all happens at low RPMs, that fact is irrelevant, as the throttle position (during the "rip'n it open") is at full open. That would be a clip or main issue, right? Correct me if I'm wrong.

KDXFreestyle · Mar 6, 2004

my problem was the needle. Raise the neele 1 position. (4 down from the top)

mnnthbx · Mar 6, 2004

I'm gonna try two down from the top. If anything, I think it's rich now.........

Braahp · Mar 6, 2004

First.............Try a simple thing like changing your plug to a BR8EG.

Mac · Mar 6, 2004

mnnthbx said:
Thanks. I think the pilot is fine. While the this all happens at low RPMs, that fact is irrelevant, as the throttle position (during the "rip'n it open") is at full open. That would be a clip or main issue, right? Correct me if I'm wrong.

The throttle is full open but you transitioned from closed. When you lug your bike at low rpm the sparkplug starts to cool off and deposits can form, this is accellerated with a rich pilot circuit or needle. Excess fuel can also accumulate in the intake due to lower air velocities. The excess fuel and cooled plug can make the "rip'n it open" seem sluggish. If you get your pilot and a/f screw set right you should easily wheelie the first three gears with a "rip'n it open"

I don't think you should choose your mainjet based on a "rip'n it open" you should do a WOT plug chop for that.

CaptainObvious · Mar 6, 2004

mnnthbx said:
Months ago when I put the 42 pilot in it helped tons. So I'm confident with that jet.

Saying that you like the 42 pilot jet is like saying you like the '69 Mets...they were only the '69 Mets in that year...and your 42 pilot only works well on those days when it is the correct jet. The pilot circuit is very sensitive to temp/humidity changes. Try adjusting the airscrew some more, you might find some help there. As the temp increases, you will find that your cold weather jetting will be too rich. You just might find that a 40 or 38 will work best this summer. That goes for the main as well; it will need a small number as it gets hotter out.

The KDX needle is a curious thing. They are never quite right. Try dropping the needle into the #2 slot, but you might want to try a different needle. Many (including me) have had luck with CEL & CEK profiles.

Something tells me that I just opend a can of worms :laugh:

mnnthbx · Mar 6, 2004

Thank you all. The bike WILL pull the front in the first three gears pretty easy. It's not that I have major problems here, just trying to fine tune it. I am running the BR8EG now, as well as a 12 tooth CS. Sorry I failed to mention it. Mac, I can tell idle RPM changes with the AS clearly, but have never seen any real differences in responce. I believe I will start with leaning the needle a clip first, then move on to the main if that doeasn't help. Again, I have no place to get a plug chop, so that is not an option.

If I were to guess, I'd bet I end up with the #2 clip and a 152. Time will tell. I will try to work it all out with my current needle, as the fewer variables the better (for me). Keep the input coming. It's a great help. Greg.

Fred T · Mar 7, 2004

OK, let me get this straight. "My bike runs funny at the first 1/4 throttle" so "I'm going to change the jets that effect the 1/4 to full throttle range to fix it" ???

I got a funny feeling that either it's not going to work or if it does then it's not the first 1/4 throttle giving you trouble.

Turn you pilot jet out 1/2 to 1 full turn if it get's better then get the next size smaller pilot.

mnnthbx · Mar 7, 2004

Fred, I think you misunderstood. It runs smooth until it's coming off the pilot (smooth until 1/4-1/3 throttle) where it becomes rough. Needle area I think........

mnnthbx · Mar 7, 2004

Well here's an update. I switched the DF2's to low tension, and it seemed to help the bottom alot. The high tension setting seemed no different than the stock cage to me.

I moved the needle to the #2. Response seemed the same. (not bad though) It idled a bit higher. The main thing, was while rolling on smoothly in third down the road, the motor was very smooth and linear, with none of the middle RPM roughness from before. How much of a sign of proper adjustment is this????????

For a comparo, I also tried the #4 slot. Response was again nearly the same. Idle was normal. The third gear role on thing was extra rough and crackly at mid RPM. Thoughts?

I figure CC will chime in sooner or later. He's the BATMAN of this forum, waiting in the wing to stop evil jetting.

G. Gearloose · Mar 7, 2004

mnnthbx said:
The main thing, was while rolling on smoothly in third down the road, the motor was very smooth and linear, with none of the middle RPM roughness from before. How much of a sign of proper adjustment is this????????

Thats a good sign. If the front end started feeling light, even better.

wanaride · Mar 8, 2004

OK, if the temps are warmer, air is less dense, less air in fuel/air per unit volume = richer jetting, right so far?

I changed to a BR8EG and it didn't help at all. I don't have the DF2 but I have the other stuff on an '03 200...

Could it be a 'lean bog' down low? That is what I have suspected with my bike for a while now (haven't fixed it yet). Have you tried installing super-rich jetting to ensure that a 'lean bog' isn't happening? Have you tried enabling the choke during this low-speed throttle roll-on to see if the bog goes away?

I suspect CC is tired of telling us "Start with the main jet because that effects response everywhere..." :worship:

mnnthbx · Mar 8, 2004

No lean bog. Again, it's very close. 100% ridable as is. As a matter of fact, when I put the DF2 to low tension it helped my issue alot. The bike will float the front end in 4th, so..... I'm curios as to what the 152 would feel like, sinse I have no place for a chop. If I'm a bit rich with the 155, I assume I'd gain a few RPM?

canyncarvr · Mar 8, 2004

From the first post:
'The "soft" bottom, is noticed when I'm at walking speed in 2nd, and quickly open the throttle to full open.'

But then:
'No ..... bog. '

???

Consider (from mac):
'The throttle is full open but you transitioned from closed.

Yep.

Along with:
'... but during the warmer weather, it is starting to feel a little flat'

Stir in a little:
'I can tell idle RPM changes with the AS clearly, but have never seen any real differences in responce'

Your pilot is likely too rich. There is no way it can be correct AND not see any 'real differences' in response with the AS adjustment.

Watch the DFII references. There are low/high tension reeds, low/high tension stops AND adjustments to both of those types of stops that are......you guessed it, low/high.

While you likely won't be able to tell which reeds you have (likely high) without looking at a set of each, the stops are different colors (gray=higher, black=lower). If you liked the difference changing the stops you have to low tension (and they are likely the black stop), consider trying a set of low tension reeds.

Considering the multiple circuits in the carb, a whole lot of what you feel as 'bog' or 'hit' is the transition from one circuit to the next...it not being smooth because one of the circuits isn't right.

There comes a time to just ride. ;)

mnnthbx · Mar 8, 2004

I'll try a 40 pilot. To be honest a 42 sounds little to me, so I was hesitant to try it. One other thing...... At walking speed, if I quickly rip it to half open throttle, it seems much crisper than if I quickly rip it to full. Can anyone make anything of that?

kdxtaz · Mar 8, 2004

Haven't been here in a while.
CC, I think I just cracked the code for your sig line! :clue:
You're a bad, bad man :|
-------------------------------------------------------
BTW, what happened to mine? :think:

wanaride · Mar 9, 2004

CC, as usual, you hit the nail on the head...

I was spending too much time on my jetting, and then it dawned on me; put the tools down and just ride it!

I'm sure it's not perfect, but it's working and I'd rather ride than wrench... :thumb:

mnnthbx · Mar 9, 2004

I ride plent. Strikes me kind of funny though..... all I see on here is jet jet jet. Then you do, and your told to forget it and ride.

Zforty5 · Mar 11, 2004

If you are at "walking speed" in second gear and its soft, why don't you just drop to first gear and get the engine in a better rpm range, thats whats nice about a six speed.
I have an 03 200, Gnarly woods, fmf spark arrestor, 45 pilot, 155 main, clip in the middle position stock needle 50:1 fuel mix, 13/49 gearing and mine too will lug if I ride it in 2cd gear at walking speed. Shift
Just my 2 cents.

Carb adjust-o-rama

mnnthbx

Mac

mnnthbx

KDXFreestyle

mnnthbx

Braahp

Mac

CaptainObvious

Formally known as RV6Junkie

mnnthbx

Fred T

mnnthbx

mnnthbx

G. Gearloose

Pigment of ur imagination

wanaride

mnnthbx

canyncarvr

mnnthbx

kdxtaz

wanaride

mnnthbx

Zforty5

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Carb adjust-o-rama

Formally known as RV6Junkie

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