Sea level jetting for a '99 with YZ timing?

I changed the timing on my '99 WR to YZ for today's ride and I can honestly say that I was impressed. It was very strong at all the throttle positions except 0-1/8 throttle. There was definitly a stronger mid-range hit and it revved up quicker. At the very bottom, however, it hesiatates enough to be noticable when I twist the throttle quickly, so I want to get this dialed in, too. It didn't do this with WR timing.

I'm hoping those out there with '99 WR with YZ timing who are jetted for sea level could share with me what their jetting is. On my bike, all the free mods done have been done to it and it's got a 170 main, 45 PJ, DTM 2nd clip, 200 MAJ, 100 PAJ. I messed with the fuel screw a little but it didn't seem to do anything one way or another. (So I'm thinking it's my pilot jet that's the culprit. But am I lean or rich? I'm guessing I'm a little rich on the bottom.)

I figured I'd get a hint from others who have the same carb/timing as me before I started in on it. Thanks in advance.

[ February 25, 2002: Message edited by: Rich in Orlando ]


I had the same issue, Changed to the 42 Pilot and the hesitation disappeared.....

Oh Yeah....While I'm thinking about it...When I was on my way out of Orlando yesterday (Going up the turnpike toward I75) I noticed an area about halfway between the toll booths on the right that appears to be regularly ridden by dirtbikes, Saw several turns that had been bermed up. What do you know about it? I think next time I'm going to bring ol blue down with me.

It only took me 6 hours from International Blvd to Atlanta Yesterday..I thought it would take much longer. The trip down took 8 hours but I had to do some Computer work in Jax along the way. I don't think I have ever seen that much rain in Orlando before in two days......

Bonzai :)

[ February 25, 2002: Message edited by: YAMAKAZE ]


First, the jetting thing: your signature says you use a 45 pilot with a 75 PAJ. Is that current or are you still using the 42? I was planning to try a 42 pilot, keeping the 100 PAJ, as my next test setup to see if that cleans up the bottom.

Second, I think you're right about the rain. We haven't got steady rain like that since the last tropical storm. I think everyone and his brother who had dirt bikes or ATVs were out riding on Sunday because of the traction and no dust.

I can't picture exactly where you are describing. But if it's where I think you're talking about, had you just got on the Turnpike from I-4 a little before that? If that's it, then you probably saw some small track that someone illegally rides on. That area looks like it's all woods but it's not. There's a lot of houses and built up areas just on the other side of the tree lines. There really aren't any off-road riding areas in Orlando where you can ride legally. Eventually the cops come and run everyone off.

HOWEVER, only an hour or so north of Orlando is an off-road paradise called the Ocala National Forest. You may have seen me describe it on Thumpertalk in the past. It's HUGE and you could ride for days and not go down the same trail twice. We were out there yesterday. Unfortunately, I submerged my bike twice :) in a couple of :DDEEP :D puddles. And I had just rebuilt the motor :D .

Next time you plan to come down here, you should definitely bring your bike. We ride almost every Sunday. There are several Thumpertalk members who ride in our group, so they're good people (obviously). :D

copy mine. add 10 to the MJ because of an open pipe. drop the needle one because you're now getting the extra 10 on the main and don't want it in the middle.

sorted. easy peasy lemon squeezy.



Not to sound thick, but are you telling me to got to, let's see...160MJ, 160MAJ,DTM-1st clip, 35PJ, 55PA(J)Screw, PS 1.5, 60 starter jet and only a tidgy bit (.024") of APJ?

I just got in from the garage and had set it up like this (changes from last config in italics): 170MJ, 200MAJ, DTM-2nd clip, 42PJ (from 45), 75PAJ (from 100), PS 1.5 (from 2.5), 60 starter jet, 0.3 sec squirt of APJ. I took it on only a short run, and it most assuredly wasn't even properly warmed up, but definitely feels crisper than before. Dare I go leaner???!!! :) I guess the answer is yes, since I've seen nothing but positive results so far from going leaner. And to think the bike had a 180 MJ and a 45 PJ when I got it!

I know this question has been done to death, but is the needle change to an EMM really worth it? Will my DTM on the 1st or second clip be anywhere close? How do I get one of those adjustable PAJ screws?

[ February 25, 2002: Message edited by: Rich in Orlando ]

Updated My Signature, Just changed the Jet last Thrusday evening and was on the road all weekend. I dropped it primarially because it felt Fat on the bottom and my plug and disks on the exhaust have been black fo awhile now. I'm gonna ride it like that this sunday and see how it works out. It did take the stumble off the bottom though. I'm also heading downward on the main if this works out. I think I should be able to go back to the 168 without a loss of torque. It's been strange lately with my jetting...the popping screams of being lean and the plug paints a rich mixture. I know I'm close because it still snaps off the line and generates lots of Mid range power.

I took the wife to Universal on Sat....Glad everything was indoors....Only took 4 hours to do the entire park since nobody else was there to speak of....

Yeah Thats the area I was talking about....

It's not that bad of a drive...I'll see if I can get MXTuner/GA426Owner/MikeM/RSK/ and the rest of our respective groups to plan a full Sunday to ride your back yard.



i recognise your name from a lot of posts. so you should have heard of "jetting Q's"? yes?

go find it and say hello to me at the bottom (thus bringing it back up)it's all there.

is it worth it? (an 'E' needle) no comment. just get on with it.

either i'm slowly turning some of you into fools or there are just a few bright people here and the fools won't move?


Yes, I've read Jetting Q's over and over again but it just hasn't seemed to want to sink in. :) Last night, I also printed up your explanation of the different needle codes you wrote up last year, studied it (several times) and I think I now understand at least a little of the subtle differences between needles.

The problem is that going leaner seems to represents, to a lot of us, a fundamental shift in the way we all think about jetting. I personally am starting from a long held belief in which more fuel must mean more power. It takes a leap of faith to believe it won't burn up the motor by going so much leaner than what it came with.

I understand why you write "just get on with it" because you must get tired of saying the same thing over and over again. Although I'm happy with the results from the most recent changes for the time being, I'm going to order the leaner jets and see how it works. Because, isn't that what I asked for in the first place?

how about if i put this spin on it. you might feel better.

"you're running rich from the factory, change to the correct jetting. this produces more power and/or the opportunity to do better MPG. the bike will start first time and choke will be necessary for around 30 seconds".


Rich....satisfied customer here with Taffy jetting + 8 on the main and dropped the needle 2-3 clips (I'm not sure on my final setting here)- the difference in jetting vs Taffy is due to my stroker silencer whereas Taffy had the Euro stock. The bike flat out rips.

I may try a slighlty leaner needle diameter as it feels a tad rich down low and I had an afterburner effect once when I shut the bike down ! I think this is happening (rich) because I ride at +-600m (1800 feet) above sea level and above.

[ March 01, 2002: Message edited by: The Missile ]

it took me a fair while to get the hang of the needle chart thingy as well rich. i was lucky enough to get a much used and copied diagram of how to get the right needle.

if i was any good with a computer i would scan it and put it up. sorry!

perhaps the next rider to order jets from sudco or allens could ask for a kiehin diagram.

the EMM is the needle i used rich.


For FCR needle diagram click here!!

Here is a tough question Taff: I am sending my cylinder off to get the 420 kit (due to the damaged Nikasil).

ANY ideas what will happen to my jetting?

I was about to write "I am doing the leap of faith", but caught myself due to the 420 kit project.

Taffy jetting works for me! :):D:D Did the whole hog in one go, yz timing,deoctopussed,etc ,etc(thanks taffy!)third time out came off and broke my collar bone,so you can imagine how much i'm itching to get back on it! :D

well done andy, i had no idea you were cracking on with that! with those dimensions i hope you played for the cherry 'n whites! blodonyurbooets boey!


IMHO you will drop MJ by only 2 but probably need to drop the needle making it all leaner.

remember the faster the air the more fuel it draws (by ratio). so don't be disappointed!

missile, sounds like it's humming now!


I called Sudco on Wednesday and ordered the whole "Taffy jetting" kit- EMM needle, PJs (I got 35,38, and 40, just in case), 160 MAJ, PA(J) screw. I already have the main jet, so now, I'm just waiting for the UPS driver to deliver me a "ripping" WR400.

Has anyone else spoke with the guy at Sudco? Did he sound like he would have rather been having teeth pulled than taking your order? He didn't sound like a happy camper. But he's getting my money, anyway.

The stuff from Sudco was waiting at my door when I got home from work--all except for the 160 MAJ. They goofed and sent me a 160 MJ. I called them and they will be sending me the MAJ right away. I went ahead and installed everything else. The PA screw was set at 3/8 of a turn out (55 PAJ), EMM on clip 5, 35 PJ and a 160 MJ. I already had a 60 SJ.

How's it work? I'm hoping the 160 MAJ will fix it. It popped occasionally at steady throttle, (5th gear at around 40 mph) and breathed hard on top. I'm not sure if the popping is from being too lean or too rich. I put in a 162 MJ and the hard breathing went away for the most part. The mid range wasn't as strong as I expected it to be-it almost feels too rich (I'm thinking about lowering the needle one clip-just like Taffy told me I should do-duh! :) ). But it did start nicely and idle smoothly. However, it did that before I made the changes.

I did notice that it took considerably longer to run the float bowl dry between MJ changes than it has in the past. Hopefully this is a sign of things to come regarding increased mpg.

[ March 05, 2002: Message edited by: Rich in Orlando ]


which pipe again please?

you might be missing only one stone from your bridge but unfortunately it's the KEYSTONE!! :)

the std MAJ means your MJ is too small which means your needle is out which means...

once you've tried it with that 160MAJ it'll all start to come together. remember everyone is now starting to dump the goodies straight in without arriving, which means folk are going to go straight at a pop and bang and have no feel for what it is that's happening.

it could be tough for the first few riders but eventually we can build up a picture.


I've got an FMF Megamax II w/11 disks. I think it breathes somewhere in between a stock pipe with and without a baffle. I agree with you about the "keystone" analogy. It seems like the main HAS to be correct before anything else can be setup properly.

And speaking of float bowls--why didn't Yamaha see fit to include a drain screw on the float bowl on this particular carburetor? The only way to fully empty it is to run it until it dies then remove the big plug on the bottom and let a whole bunch more fuel run out all over the motor!!

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