Jetting questions

[eyesky2002]

Hey kids...

Finally got all my jets and a new needle in and it's time to get this beat jetted right!

Current set up is 39mm PWK with a 178 / 55 / and the dreaded CGJ R1368N. It runs rich across the RPM range, but more so in the pilot circuit. Also it has tons of snappy top end power, but a bit slow on the low to mid range throttle response. Air screw seems to do very little to the performance.

Am I doing right lowering the pilot?

I got a 45, 48, 50 and 52 pilot and a 172, 175 main. Gonna start by dropping the pilot a jet at a time, then move on to the main.

I also got a 1470 needle but did not realize it was a 1470D till I got home ( damn KTM dealer ) . This is where I need help, should I try the D or have them order me a N and then exchange the D? Hate to try it if it will not work as they raped me out of $16.00 for the needle

[AlisoBob]

The needle is 80% of what you ride on. The pilot is for idling, the Main is for WFO.

The last letter is the legnth from the clip slots, the the functioning area on the needle.

Theres a chance that the needle has some overlap ( Like your needle in the 2nd slot is like our needle in the 4th slot).... but why dick with it.

Get the correct needle.

[bigpower]

I've been messin with carbs over the weekend. The 98 my son was riding has the 39.5 PWK on it and the setup this weekend, at 75f, 1100ft elevation 48 pilot, 175 main, 1.25 out on the air screw, DGN needle on the 4th clip. A little fat up top, but returned 25MPG on a combination of single track and open fire roads. Need to drop it one size on the main, but other than that good for the conditions.

I should note that motor is .020 over, and ported, but a good ball park to get you goin.

Like Bob said, get the correct needle.

[pstoffers]

I run a 39.5 PWK with a DGJ 48 172 everywhere!!! An thats all I got too say about that

[eyesky2002]

All this is testing warmed up and riping a dirt alley behind the house. Track is rained out for tomorrow, so Thursday will be the first day I can get it on a track. Also running a 99 250 ignition dead center on timing, PC Works/304 exhaust, 40:1 (Castor 927) 50/50 107 octane and 91 mix, between 900-1100 elevation and in the 80's.

I tried the 50, seemed to have better off idle response, same mid stumble and still no effect with the screw 0-3 turns. Today I threw in the 45, seemed to have more snap. At 2 turns out it starts idling up stopped at 3 turns out, seemed smoothest at 2 1/4. Go lower on the pilot? I can exchange the 48 and 52 since I did not use them.

Decided I would just try the needle and go 2nd from the top to make up for the D to N L1 length difference. No more stumble, just instant.. well great response Made a mid range run / shut down, plug is much dryer and just starting brown at the tip. Ordered a 1470N (DGL) needle and will play with it when it gets here.

I also dropped the main to the 175... Can't really use warp speed in the alley, so I will get to the track early and make few high speed runs in the pit and adjust accordingly.

Thanks for the input!

[AlisoBob]

Sounds like your on the right track.....

[dubious01]

I agree sounds liek your pilot is finally close enough you can see changes with the air screw.
before you were too far out on the pilot.
In fact all the carb guys will tell you if your airscrew is between 1.5 and 2,5 turns, and it peaked by 3 turns your spot on!
good work

[eyesky2002]

I agree sounds liek your pilot is finally close enough you can see changes with the air screw.
before you were too far out on the pilot.
In fact all the carb guys will tell you if your airscrew is between 1.5 and 2,5 turns, and it peaked by 3 turns your spot on!
good work

Thanks... Still working on the needle, its close; but it seemed like it had more mid to top with the 1368 / 178 combo.... Plus I keep thinking I see a blue tint to my pipe when I pull in from a few hard laps. I put them back in and went a little leaner on the needle clip. Will see how it goes Thursday, maybe my 1470N will show up before then as well.

[2strokeforever]

i am getting my bike dialed in too stock except for PC pipe and type296
at 1000-3000ft with a 39.5pwk and i got a 1472/ DGN 42 pilot 170 main air screw 2 turns out... its still a tiny bit rich but very close

i think it revs really high for a 500, does anyone know if a well jeted 500 will hit the rev limiter? with a 140lb guy going up a hill in 2nd, with no traction

me and 2 of my friends are pretty sure that i am bouncing off the limiter, but i never had that happen with any other 2 strokes i rode?
does anyone know what the limiter is set at?
looks like i need a 250 ignition


the motor has less than 40 hours so i know nothing is wrong with it

[gregrobo]

i am getting my bike dialed in too stock except for PC pipe and type296
at 1000-3000ft with a 39.5pwk and i got a 1472/ DGN 42 pilot 170 main air screw 2 turns out... its still a tiny bit rich but very close

i think it revs really high for a 500, does anyone know if a well jeted 500 will hit the rev limiter? with a 140lb guy going up a hill in 2nd, with no traction

me and 2 of my friends are pretty sure that i am bouncing off the limiter, but i never had that happen with any other 2 strokes i rode?
does anyone know what the limiter is set at?
looks like i need a 250 ignition


the motor has less than 40 hours so i know nothing is wrong with it

sounds like you dont need a 250 ignition the 500 isnt built to rev

[100hp honda]

i am getting my bike dialed in too stock except for PC pipe and type296
at 1000-3000ft with a 39.5pwk and i got a 1472/ DGN 42 pilot 170 main air screw 2 turns out... its still a tiny bit rich but very close

i think it revs really high for a 500, does anyone know if a well jeted 500 will hit the rev limiter? with a 140lb guy going up a hill in 2nd, with no traction

me and 2 of my friends are pretty sure that i am bouncing off the limiter, but i never had that happen with any other 2 strokes i rode?
does anyone know what the limiter is set at?
looks like i need a 250 ignition

mine has done that before. on the very top it pops like a rev limiter, main is 1 or 2 clicks too big.

[2strokeforever]

thanks clyde, my main is a little big ill try a 168 and see if it goes away

[eyesky2002]

thanks clyde, my main is a little big ill try a 168 and see if it goes away

Turned out mine runs better with the 178 main and needle is back to the 1368N 1 up from the bottom. Runs GREAT!!! I also already have a 13 on the front Guess I just suck

[AlisoBob]

I went 51 miles today, still have plenty of gas left in my 2.5 gal tank.... even gave another rider a quart from my tank.

A well tuned bike is a wonderful thing.

[2strokeforever]

A well tuned bike is a wonderful thing.

x2