Jetting!!! Again and again and again!

[staffylad]

mynes fouling plugs now,was running fine lastweek at the track ,25:1 mix ,pilot 2turns out ,changed gas put fresh mix in today fouled 2 plugs ,gonna turn screw out 1 n half turns see wat happens.

[Twosmokerfan]

Hi everyone,

After playing with my 500 for the last year or so, I bit the bullet and bought a pwk39 as nothing I did to the carb on the bike when I bought it made it run well.  I am putting the down to worn internals an the emulsion tube (or needle jet, depending on terminology).

Since then, it is jetted nicely now for idle (45p, n82m on the top clip and num7 slide, with a 165 main. I ride in hotter climates and only really up to 1000m)

I can't seem to lean out the mid range any more as the plug is always black and I went and got my hands on a n82n and p needles. The question I have is "Is the n needle on the bottom clip leaner than the m needle on the top clip. And is it the same for the p compared to the n".

I know when you play with other needles like cem vs a dem needle, it leans off the first part of the throttle opening, but I was hoping someone could tell me about the n82 series.

TSF

[Twosmokerfan]

Anybody?

[reklessj]

The lower the clip position the richen you get. As far as the p and n go, you'll have to wait for someone else to chime in

[Foxx4Beaver]

P is leaner than the N...I run a T.

[sandblaster]

[ylwgtr]

he wants to know the comparsion between the n and m needle in respect to full lean on one and full rich on the other.....my advice would be to map both needles....you can work it out that way

[Twosmokerfan]

Yes ylwgtr, that is the answer i am looking for.

Well, I tried the N82n on the bottom clip (a short video link on the video post) and it worked well. Better than the m needle. Ran cleaner and pulled clean from down low. Tried it then on the middle clip (leaning it off) and I felt it might have been too lean. Went second clip from the bottom. I have concluded that the n is leaner than the m and the bike is running very nicely now. It idles no problems and doesn't load up in the slow stuff. Only a slight puff of smoke when cracked from idle and the throttle then closed. I am more than happy now.

Final settings at this stage:
P 48
Screw 1.5 out
Needle n82n on second clip from bottom
Main 165.

TSF

[stujordan]

For the hardcore...

52 pilot 2.5 turns
150 main
N82R needle in 1st position (leanest)
320 ft above sea level

...not that im advising anyone to do this...

My pig will get along...my life has flashed before my eyes soooo many times

[Foxx4Beaver]

holy boiler maker ...how much WOT runs are you doing with those settings?...with what carb, and type of fuel and pre-mix ?

[stujordan]

Stock pwk 39 carb and 7 slide
90 octane free of ethanol
32:1 supertech (cheap walmart brand)
Both air box vents open
Stock porting and squish....

I never hesitate WOT, but dont need it to smoke a 4-pump-chump (friends with 4-strokers)  

[Foxx4Beaver]

have ya done any plug chops with those settings...I would have to think the plug would look "brand new" white, from being so lean...but, I've never gone that lean before either, so I could be wrong.
no pinging with those settings?

[stujordan]

If it pings its not noticeable...the plug is actually brownish black, but I dont hit WOT in every gear...

I see people reasoning going lean on the pilot and rich on the main is the ticket...think they should talk to desert racers for the best advice....bought mine from such a person.  It has over 20 hours since I bought it from the dude...

[stujordan]

Just read a post on another site that runs a 148 and a 48....might need to try that with a N82T needle...as is im a little rich....

Thoughts?

[Foxx4Beaver]

I wouldn't, but I ride in the upper revs for the most part...
when was the last time you did a compression check...or rebuilt the top-end?