a little jetting help please

ohgood · Post by **ohgood** » 08:00 pm May 30 2015

hmm, getting closer

and

I'm amazed that it still hiccups at constant throttle, barely idles, and burbles between 1/8-1/4, but I'm getting closer. if i ever nail down perfect jetting I'm going to loctite every thing on the carb and but another one. lol

cornishwrecker220 · Post by **cornishwrecker220** » 02:40 pm May 31 2015

The plug looks reasonably `dry` ....the colour looks fairly good too, If the plug was wet or oily then yep I`d say it was a jetting issue but it isn't ..
From the pic it appears to have a carbon or similar build up of something on the electrode ..?
I may be wrong here but I don't think its a fueling issue, but more along the lines of electrical instead.

6 Riders · Post by **6 Riders** » 04:34 pm May 31 2015

Have you tried un plugging your headlight and riding it? Just a shot in the dark, but easy enough to do.

ohgood · Post by **ohgood** » 07:46 pm May 31 2015

cornishwrecker220 wrote:The plug looks reasonably `dry` ....the colour looks fairly good too, If the plug was wet or oily then yep I`d say it was a jetting issue but it isn't ..
From the pic it appears to have a carbon or similar build up of something on the electrode ..?
I may be wrong here but I don't think its a fueling issue, but more along the lines of electrical instead.

yes, it's carbon. it fouls the br8eix (iridium) plugs in 10-15 minutes of street riding, doesn't matter if i'm all over the pipe or just cruising.

this one from today, beat the snot out of the bike on nasty single/double track:

the camera flash is playing on this one, it's not really biscuit brown, it's more gray on the insulator. the rim of the threaded section is however, biscuit brown. the tip is actually ashy gray to biscuit.

that was after 5 1/2 hours of single track, and then a 4th gear WOT plug chop.

38/ 138, middle clip on the needle, fresh air filter, 17mm float, 32:1 Lucas oil.

also went from retarded timing position to advanced. sheeee dawgy she pulls good on the pipe !

had a good time riding today, but that burble really needs to go away.

ohgood · Post by **ohgood** » 07:48 pm May 31 2015

6 Riders wrote:Have you tried un plugging your headlight and riding it? Just a shot in the dark, but easy enough to do.

no i have not. i'll do that tomorrow afternoon. i've forgotten which CDI i have on the bike right now, so that will be another thing to swap/test.

i thought i blew a head gasket and case seal today... the sight glass was fogged all to hell from humidity... then i picked the bike up off the ground and beautiful RED atf was right up to the proper level, just like the last 3 rides.

...light at the end of the tunnel baby...

ohgood · Post by **ohgood** » 05:27 pm Jun 01 2015

headlights unplugged, no difference
extra cdi, no difference
timing at first, middle, or last mark, the power is better, but the stuttering still exactly the same.

maybe it's just how kdx run when there isn't a load or accelerating?

one more thing, there is no splooge

Post by **Julien D** » 08:40 pm Jun 01 2015

Still sounds like a leaky jet block gasket to me. I know you said it's new, but maybe a double check? And yeah, stay away from them iridium plugs. Any real benefit other than the weight savings in your wallet is debatable, and if you're on the rich side of perfect, they will foul more easily. As you've seen...

6 Riders · Post by **6 Riders** » 11:29 pm Jun 01 2015

Since you just flipped your reeds, go back to that as well as double checking the jet block gasket.

ohgood · Post by **ohgood** » 07:03 am Jun 02 2015

6 Riders wrote:Since you just flipped your reeds, go back to that as well as double checking the jet block gasket.

new (again) rreeds are arriving this week. i'll check the reed gasket, jet block gasket, and replace the reeds either this week or next.

24 hour race @ perry mountain (on a rmx250) is coming up saturday, so sunday will be a real day of rest ;-)

ohgood · Post by **ohgood** » 11:05 am Aug 09 2015

update, another request for help with two docent setups:

gnarly woods pipe with pro circuit
new reeds
clean filter
138 main
38 idler
2nd clip from the top
15-17mm float height the carb is worn
2 turns out on air screw
no air box lid
40:1 Lucas semi synthetic

results: starts fine, runs very well, great pull and acceleration,

but only 20mpg, (this is my main concern )

on a dirt road ride around 20-45 mph, for 80 miles with some street and trails mixed in.
this is the plug after eighty miles:

(true color is perfect biscuit tan both on insulated and electrode)

BUT WITH-
stock pipe, stock arrestor:
new reeds
clean filter
138 main
38 idler
2nd clip from the top
15-17mm float height the carb is worn
2 turns out on air screw
no air box lid
40:1 Lucas semi synthetic

results: starts fine, runs well, expected less pull and acceleration

but only 18mpg, (this is my main concern )

this is the plug after 30 miles trail riding:

(true color is very light tan to gray both on insulated and electrode)

the gnarly pipe and pro circuit appear to be a better combination for plug color, than the stock pipe and arrestor , with the same jetting?

... edited,....

aha ! I thought the second picture was the beginning of lean, but it turned out to be the edge of RICH, as the next test with
142
42
2nd clip from top
and 2 turns out
showed in this test ride picture:

which is clearly on its way to carbon/oil fouling.

OK, cool, I'm just surprised that the rich (second picture) is so white instead of going black from the change of gnarly pipe to stock exhaust.

OK, so this means I need to lean it out even more for the stock pipe ... like:

135
35
2nd clip
2 turns out

I'm just afraid of getting that close to what people usually call a lean setup.

Silverfox · Post by **Silverfox** » 06:47 pm Aug 09 2015

I would try 38 pilot second clip and 142 with stock pipe. 145 with gnarley pipe.

ohgood · Post by **ohgood** » 09:36 pm Aug 09 2015

Silverfox wrote:I would try 38 pilot second clip and 142 with stock pipe. 145 with gnarley pipe.

will try that tomorrow

ohgood · Post by **ohgood** » 09:36 pm Aug 09 2015

Silverfox wrote:I would try 38 pilot second clip and 142 with stock pipe. 145 with gnarley pipe.

will try that tomorrow

ohgood · Post by **ohgood** » 09:57 pm Apr 04 2016

i bought a new pwk 35, and it solved everything.

like, mystery of the universe too, everthing ;-)

MotoArts · Post by **MotoArts** » 12:35 am Jun 20 2016

Please let me/us know what you ended up with jetting wise in the new 35.

I have the same issues you had with the OE 33 carb on my 220... 38/142 jets, new jet block gasket, needle all the way down, PC pipe and silencer, stock everything else... still rich sputters slightly between 1/4 and 1/2-ish throttle. Runs like a bandit on the main, unpredictable anywhere else. It's rideable, but goes through fuel like there's a hole in the bottom of the gas tank and just does not sound right. It actually eats gas at twice the rate of my son's perfectly jetted '99 CR250, but surprisingly has zero spooge from the exhaust.

Been riding bikes and tuning cars for 40 of my 50 years, never had a carb as unresponsive to adjustment like this one is. :(

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