PILOT CURCUIT

[CHUCKY]

OK I'm hooked. Just been reading Jetting Q's, it's 0120 hour and I have to get up at 0415 hour. Can anyone tell me where in OZ I can get a Pilot air screw or a website for Sudco, etc. I have the annoying vibration/misfire just off tickover (just when the slide is raised) and would like to play around with the pilot curcuit. Also I can turn the pilot screw right in and it still runs ???. From previous bikes this would stop. The bike also revs out well to a stage then take a little bit of time to hit the rev limiter in 4th with 14/50 gearing.

I am running a WR426 2001 Aussie model with :

Stock stainless pipe

Airbox lid off

YZ timing

Aircut mod

BK mod

42 PJ

75 PAJ

OBELN #3

162 MJ

200 MAJ

After reading the Jetting Q's I have a much better understanding of all the above but anyone's thoughts/ideas (Taffy/JD) would be appreciated. Hoped I didn't put anyone to sleep ?.

Chucky.

[Hick]

Zzzzzzz….

Sounds like your pilot may be too big. Unless the idle is set very high the bike should not run with the pilot screw all in. What is your elevation??

Also, I think the 75 Pilot Air may be too small for your setup and could also be contributing to your hang-ups just off tickover.

You may try a high speed pass with the MAJ removed (some guys have even drilled this passage larger) and see if it tops out more crisply.

Never been to Oz, but here is some phone numbers for US carb supply places. You need two parts for the Air Screw, the screw and a small spring. Should total about fourteen US dollars:

Sudco: 800-998-3529

Carb Parts: 216-524-1599

Hope this helps.

[CHUCKY]

Hick,

I'm led to believe I'm at about 3000ft. I have had the opportunity to try a 100 PAJ and in terms of it running with no PS, it still ran with a 45, 42 & 38 which I tried for the fun of it. 100 PAJ didn't help rough spot. I wish to get a PAS to experiment with because the OZ carb part prices are dear as we have established. The jets I have are collected through previous bikes, which I have the above PJ and a 55, 75 & 100 PAJ, OBDQR & OBELN needle, 155,160,162,165,170 MJ. These will all work.

Dont like the idea of drilling jets.

People seem to have varying result/theories with the pilot curcuit and with a PAS I will test all the read suggetions. What about a MAS ?.

I have been busy riding rather than fiddling until I got a computer and thought it was about time. Also short of money and with the aussie parts prices, I have been sitting in the back seat reading. I haven't had a computer long and after a year on the bike with no one in OZ mags etc providing info, I have know got a link. Thanks TT. I think I put you to sleep again.

Chucky.

[Hick]

Originally posted by CHUCKY:

Hick,

I'm led to believe I'm at about 3000ft. I have had the opportunity to try a 100 PAJ and in terms of it running with no PS, it still ran with a 45, 42 & 38 which I tried for the fun of it. 100 PAJ didn't help rough spot. I wish to get a PAS to experiment with because the OZ carb part prices are dear as we have established.

Chucky.

That is weird. My bike will not idle with the mixture screw all in.

I run about an 85 or so on an adjustable PAS and a 40 pilot, 160 main, EKQ needle, #3 clip. I ride in the SW dez, arid and pretty warm, about 4k ft. of elevation.

So the straight diameter on your needle (letter N vs. my Q and stock US YZ is a P) seems rich to me, but I have a US YZ, I’m not familiar at all w/ what type of exhaust you have, but I would think that the pilot jet and needle straight are where you need to look for your low throttle setting response.

[Mark_Cantrell]

Hick,

It will with a 42 or 45 PJ.

mwc

[Hick]

Originally posted by Mark Cantrell:

Hick,

It will with a 42 or 45 PJ.

mwc

Yeah, I actually tried that recently (shutting off pilot screw and it did die) as a result of a post you made, but long ago I had also noticed, by accident, that my '00 would idle and run with a 42 pilot and the screw all in.

[skippy]

OK,

I've been getting my carby parts from Show & go motorcycles in south australia. ph 0883760333 or www.showandgo.com.au They are the sudco parts importer. Needles $18, jets $9, paj screw with spring $36, Postage to Newcastle is $7.50.

I was also told of another company called Nardek 0299752650 in sydney that sell the same parts but i haven't brought anything from them so i can't comment on them.

I hope this helps.

[Taffy]

there isn't a MAS. you can drill them out if you wish and a 1.6mm is a #160 etc etc.

to pull out the MAJ is the equivelant of 2.35mm approx.

your pipe means that we have very similar circumstances. ok, you're on a 426 with a later carb but that means very little. and 3,00 feet up ain't a big change.

i would have said that the MJ is about right but that the needle is too lean/low.

i think that your pilot circuit is too rich so that PAS should come down to #60 and a 38PJ.

i'm not getting the feedback (especially from the americans) to help draw a big picture. everyone is fitting in the jets and either asking Qs or saying diddly-squeek.

Taffy

Taffy

[CHUCKY]

Taffy,

so in terms of the all the air jets it means that if you divide by 100 it gives you the millimetre size ?. I was going to make a number of PAJ & MAJ blanks and would like to know the above. Thanks for the help.

Chucky.

[Taffy]

i can only say that that is true of the MAJ but it may be true of the PAJ as well.

i wouldn't want to drill a PJ though! that really is asking for trouble.

what if it still doesn't run right? what are you going toblame then?

dodgy ground i'd say.

officially they are meant to be measured by what they flow and in such a time etc.

Taffy