EMM needle and de-octopus question

I'm not looking for a big mid-range hit, looking for smooth power from idle and up.

About to de-octopus and set my carb to Taffy's jetting specs., including the APJ mod., and ordering the PAJ-screw. Apparently I can leave my start jet at 60 and set my PA(J)S to whatever number I desire?

If I were to order a range of pilot jets, mainjets, main air jets, and starter jets, any suggestions?

What's the part number for the EMM needle?

[ May 08, 2002: Message edited by: Littlefoot ]

the needle is N427-OCEMM

you may have trouble getting it but on jetting Qs there are a list of needles that will do. as long as you get the E?M or E?N you'll be ok.

35 and 38 PJ will do along with the PAS.

155/158/160/162 MJ



[ May 08, 2002: Message edited by: Taffy ]


I just received a EMM from SUDCO. It was on backorder but the order cleared early. Try them. http://www.sudco.com/


I have a question. I was reading Pat Burns tuning page and it states that the third letter is the starting diameter of the needle and the letters at beginning of the alphabet are richer(thinner) and the letters toward the end are Leaner(thicker). So how can a E_M be similar to a E_N. Or am I spitting hairs. Also, in my manual on page 7-6 there are some graphs that lead me to believe the a _ _ N would be richer than a _ _ M which after reading Pat Burns I find the opposite. Can you help clear this up. :)

Pete :D

I ordered the EMM from SUDCO a couple days ago, they said they had them in stock.


Wasn't there someone who said there is a dealer in OHIO, US that had some of the EMM needles.

Anybody know who the dealer is?

a ??M needle is thinner than a ??N needle so it is slightly richer. the M needle is about spot on to rich. the N i can't for but i guestimated that it would be about right because the next needle-the P-has a flat spot as you move off but do JD and hick listen...


I just ordered MJ150+some others, MAJ160, EMM needle, PA(J)S & spring, PJ 35/38 from Sudco. They had all of them in stock. I expect to receive my order middle to end of next week.

They don't sell the Start jet, did you have to go to Yamaha for this?

no need for it right now.

it's all about how much choke and how long you need it anyway. that starter jet is what everyone took OUT of the early WR's to do the de-octopuss. so there'll be a few around.



Your manual is wrong and Taffy/Patrick Burns are right, just that simple. "M" is a richer (smaller) diameter than "N".


I'm still listening, but keep in mind the version of carb on the '00 and newer Yamaha's has the FCR2 carburetor body. That .01-.02mm needle diameter difference from EMM to EMN/EKP may have something to do with it. I feel the flat spot on my '02 KTM and it wasn't there on my '00 WR with the FCR2.

Clark sent me a modified EMN from his '99 in September 2000 and it measured closer to EMM. There has always been a suspicion, but not confirmed. Notice the '98/99 WR's and all KTM's (except Calif. G models) use DTM. None of the Yamaha's since '99 have used any diameter richer than EKP. Whether it's slide orientation vs. the body or whatever there may be something to it. This isn't conclusive, but it's only .01mm (EMM vs EMN) and just from 0-1/4 throttle.


JD and Taffy,

Thanks for clearing that up. I appreciate the help with my jetting, but I also want to understand what I'm doing with the changes that I make and the ones that you gents suggest that I make. I bought the EMM needle and plan on testing Taffy's setup this weekend if my pilot Jets ever get here. Do you think I will notice a difference in 0 - 1/4 throttle between the EMM and the EKN needle that I already have in?

Pete :)

i think you will and you'll learn a great deal from it. JD and myself? we'd rather hear what it's like with the correct PC jets in. the moment you feel an oohh or an aahh i'll just think "mmm, whaen he gets the correct PC...."

i ran my tests with the APJ disconnected. i'm going to put money on this and say that the bike will start and run the same on both (given that you remember that for any valid testing there is a 1 clip difference between the two (EMM=c4 so the EKN=3)but that the M will eight-stroke slightly on tickover (idle).

if you remember running a bike too long on choke and it's about to stall-that's eight stroking!!!


I received hardware from Sudco today.

This is what came out of carb;

maj 200, mj 168, paj 75, pj45, ps 2 3/4, sj 60

Haven't pulled the needle yet, I'll do that tomorrow.

Here's how it's goin in;


maj 160, mj 150, EMM #5, pa(j)s ?, pj 35, ps 1.5, sj 60, Taffy apj mod,(used RC car rod stops drilled out, fits nicely under boot)


How many turns on the pa(j)s for what jet?

Hopefully I'll be out riding this weekend. Have to fix the son's KX80 also, countershaft seal went.

[ May 14, 2002: Message edited by: Littlefoot ]

[ May 14, 2002: Message edited by: Littlefoot ]


Are you YZ or WR timed?

Pete :)

1/4 turn out from closed = 45PAJ

3/8 = 55 PAJ

1/2 = 65 PAJ

with the 35 PJ i recommend a 45 PAJ or up to 55PAJ. so try to turn it 1/4 turn out /+ a smidgeon! (that's a little bit to you!)

just tell me your pipe, and year again littlefoot.


has anybody in calif tried taffy's jetting specs on there bike.i gave it a try but my bike ran like there was tubesock stuffed in floatbowl.i used emm nj[tried every position],165maj,160mj,38pj,ps 1/2 to 3 1\2 out.i know a 160 maj was recommend but 165 is all i had[it shouldnt have made that big of difference].bike was very hard to start and starved for gas when i got on it. i live in ca. at sea level 15 miles from ocean.after a few hours of trying different jetting combinations i put jetting back to 200maj,185mj,48pj,dvp needle 3rd clip,ps 2 turns out and bike runs great again.i dont know if its climate and air density in my area or my motor but emm nj didnt work for me.i'd like to know if any cali. residents have had success using emm nj.

I am currently 1999 400, WR timed, US WR pipe, but I have a modfied exhaust tip, removed the stock baffle, machined a cylinder of aluminum,(2.5 to 3 in long), to fit in it's place, then punched a hole in the aluminium to acccomodate a piece of 3/4 inch copper tubing about 7 in. long, kept drilling small holes in the copper pipe portion that is inside the spark arrestor until walked up on the 94dB limit in Michigan.


I tryed taffy's jetting & found that the bike performed better useing my own idears.

160maj was too rich in the mid range & top.so i went back to 200maj. now i use 170mj. I'm useing a EMM #5 which is good but it does make the bike eight stroke at idle. also i'm useing a 38 pj & paj screw set at half a turn out.[65].

Thats for yz timeing.

wr timeing is completly different.

200maj 150mj drm#4 38pj 65paj.

it's a shame you two didn't say anything at the time :D:)


just add 5 to the previously suggested MJ size. the E needle and YZ timing are more suited together.


[ May 15, 2002: Message edited by: Taffy ]

Use a 155mj instead of a 150mj? I would not have guessed the WR timing liked a richer mix.

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