Needle Valve vs Throttle Valve Size vs Clip Position

[mandark1967]

You may remember my other posts concerning the jetting issues I was experiencing after replacing the OEM PWK33 with a PWK35mm carb om my KDX220

As I was researching my jetting issues I got some great on pilot jets and main jets, (Thanks!) but no one really went into depth about needle valves and the part they play in the proper operation of your carburetor.

Some may suggest I read the tech tips section at the justKDX site, but it doesn't mention more than a very small section about throttle valves.

I emailed some of the sites and I was always steered towards some "standard" kit consisting of pilot and main (and maybe a lean needle and a rich needle).

My question is specifically about throttle valves.

I noticed when I changed out my carbs that the PWK33 uses a throttle valve marked #5

The PWK35mm I got has a #6 throttle valve (higher # = Leaner)

What I'm experiencing right now is as follows:

Suzuki CCI Oil & 93 Octane Gas at a 40:1 ratio
Clean Air Filter & freshly packed silencer
NGK BR8ES
Pilot - 45
Main - 152
Needle - DG K (2nd position from top)
Air Screw 1.75 turns out
Throttle Valve #6 (Also called Slide Valve)

Start bike (with choke since we're having a major cold spell for our area with temps in the low 30's this morning) and let it warm up a bit.

For a small period of time, say one minute or so after turning the choke off, it smokes a moderate amount when the throttle is blipped, then barely any smoke at all comes out the exhaust. No dripping oil or anything like that.

There doesn't seem to be any pinging or detonation anywhere.

I'm getting some bogging right around 1/8 to 1/4 throttle. It doesn't happen all the time, but it does stumble a bit every now and then.

Once I hit 1/4 throttle and above, the bike comes alive and hits a LOT harder than I ever remember it hitting before. (As in it comes up on 1 wheel in the first 3 gears wayyyy too easily)

If I were to replace the needle valve, I'm assuming I need something with a thicker diameter to lean it out a bit at that 1/8 to 1/4 range. Since I have no idea what the specs on a DG K needle are, how am I supposed to find something different? (as compared to a DG K)

Or, should I go up to the last clip position since I have no idea what the next size needle is?

or,

Couldn't I instead replace the #6 throttle valve with a #6.5? Or would that be too lean?

 

[TWMOODY]

If you are at an altitude of 700' go 42/152 or 40/152 jets and
get a DEL needle put on the 3 or 4th clip position.
DEK and CEK needles are for RB moded carbs only.
If you really want to do your bike a favor get the R&B carb
and head mod.
Costs just over 200.00 and is WELL spent money.
If you are doing reeds go V Force 3 forget the rad valve
as they come apart sending pieces into your engine.

 

[mandark1967]

Uhm...I kinda feel like an idiot.

All the needles I've seen were always marked with the full N427-48_ _ _ marking, and not just the last 3 letter section. So...when I saw DG K (note the space between the DG and the K) I assumed it was a different company, not the subsetting within the N427-48_ _ _ range. lol

I'll call Sudco Monday morning and see if they can't ship me one out

 

[krazyinski]

Uhm...I kinda feel like an idiot.

All the needles I've seen were always marked with the full N427-48_ _ _ marking, and not just the last 3 letter section. So...when I saw DG K (note the space between the DG and the K) I assumed it was a different company, not the subsetting within the N427-48_ _ _ range. lol

I'll call Sudco Monday morning and see if they can't ship me one out

hold up!! try pats small engine here to check on needles. but if you have a DGK in it then you should be fine just raising the needle one clip position.

 

[whenfoxforks-ruled]

The one notch higher on the needle should do the job,warmer weather and you will need a leaner needle.

 

[mandark1967]

I called Sudco this morning and ordered DEL, DEK, and DEM needles.

That should do me for a while. I already have pilots and mains 3 up and down from stock

 

[G. Gearloose]

Somebody needs James Dean's jetting calculator-active speadsheet; look it up, its the ****.