DSP/YZ Timing Jetting Info...

Hi all.

FYI: '00 WR Jetting for 3,000 - 6,000 feet, 65 +/- degrees F.

Just completed the YZ timing conversion and installed a DSP pipe (Non-tapered model, fat everywhere). Changed the jetting to the recommended setting (180 main / 48 pilot). Have not had a chance to ride it yet at the mentioned altitude, but my initial feeling is I'm a bit rich. When cold, it starts on first kick without using the choke. :)

Before the timing and pipe, I was running with the baffle and snorkel removed. Had to raise the needle by one grove. Ran PERFECTLY. I'm thinking I will have to move the needle back down by at least one grove, maybe two. I have been told numerous times that the stock needle is the one to use for the '00 WR's.

To those of you who are wondering which pipe to get, forget the others. The DSP pipe is awesome! After test riding it down my street, I can say my arms are a few inches longer now. HUGE difference, especially after converting to the YZ timing spec.

I am going riding at about 4,500 feet this Saturday and will post my final jetting settings after I get it dialed.


I think you are on the right track.

I have a 2000 with the DSP pipe, but the tapered header. I have YZ timing, cover removed, 180 main, 48 pilot, stock needle and position.

I can't find any problems with this set-up. After a 6 hour trail ride on Saturday, everything seems to be in order.

In addition the dealer made the same changes to a customer bike just a day before I bought my pipe and said that was the same set up they used for jetting. Stock needle and clip position.

Hope that helps.

Jetting Update:

DSP recommends a 180 main & 48 pilot. This turned out to be real rich @ 4000 feet. Just picked a 178 main and 45 pilot. Gonna try this setup this weekend & let you know...


I would be interested in what you find out.

I am using a 180/48 with 2 turns out on the screw. DSP pipe, tapered header, yz timing, airbox cover removed.

I thought at Silverlake (isn't that about 4,000ft?) all the way to arrowhead (probably higher), that the carburation was pretty good. I didn't notice any holes in the carburation. But it is possible that things could be leaned out and still run well or show improvement.

I am interested to hear your results.

Let me know how it worked out.



I just tried the 178/45 combo (friday at 9:00pm).

I didn't like it at all. It felt crappy down low and it felt crappy once on the main jet as well. Always struggling for acceleration and power.

The only consideration is that it is nice and chilly tonight with little moisture in the air. The exact conditions to exacerbate a lean mixture.

So maybe at 8,000ft this might work. But for myself I confirmed that the 180/48 is the right setup for my bike.

The 180/48 is exactly what Beach Yamaha set another customers bike to when they installed the DSP pipe on a bike. They used an exhaust gas analyzer as well.

Was it as crappy on your bike? I would be shocked if it works on yours.



You guys are right, the 180/48 combo works best. When I first installed this setting it was very rich, the exhaust smelled like gasoline and had jet black residue on the tailpipe. It also had to rev way up before it cleared out. Much sputtering in mid-range and bogging down low.

The 178/45 setting turns out to be too lean and an over-compensation for my problem. Like you said, "crappy". Sorry if I lead you down the wrong road. I should have gotten back to you sooner to save you the trouble (and the $10) of jetting incorrectly.

I'm still fiddling with it, but am getting close. The 180/48's are back in and the needle is dropped down to the second notch from the top. Air screw is at 1-3/4 turns out (I've tried 2 turns). Much better, but still not perfect but will be soon. I guess I'm a glutton for carb disassembly.

I have also changed the countershaft sprocket from the stock 14 tooth to a 15 tooth unit. This not only makes the bike more fun to ride, but has helped me dial in the jetting by providing more room to feel any flat spots and/or hesitations the motor may have. With the stock sprocket there was no time to "feel" what was going on, just shift shift shift. This change made such an improvement that I'm thinking about going with a 15/48 setup, after my jetting is finally dialed.

Also, keep in mind that our bike are a bit different. I left the airbox lid on, have the non-tapered pipe, and the thing is not a California bike. I'm not sure what the difference is between the Cal model and the '49ers are (nobody wants to tell me when I ask, but the dealer said I was lucky to have a '49er), but this may have something to do with the difference in jetting between out bikes.

Take care -



I don't think there is any difference between the 49 state model and the California model.

The manual that came with the bike is extremely good and makes clear reference to USA specs and European specs. But no place do they denote any diffence between 49 and Cal models.

The manual is too detailed to imagine that if there was a difference that they left those details out.

Regarding your bike. The air box lid is probably the biggest difference.

I have no experience with dirt bikes but I have owned about 5 street bikes and fiddled around with Dyno jet kits on 4/5. I also have a mechanical engineering degree and consider myself a student of the sport.

Here is my point. Every articles that I have read regarding street bike after market modifications says it is always the intake side that most greatly affects the jetting.

When magazines changed to an aftermarket pipe (with no change on the intake side), many times no jetting was required or only mininal changes where required. Like one size up on the main. Even going to an aftermarket STOCK REPLACEMENT K&N filter requires little or no change in the jetting.

The one big change that required major jetting changes was removing the airbox completely and going with the individual filters. And by removing the lid from the air filter box we are in essence removing the box because I am assuming that there is almost no restriction for air to get to the filter now.

Now our bikes maybe slightly different from these street bikes since the stock exhaust is so pathetic and an aftermarket exhaust does make a big difference.

But consider this. Carburators flow gas based upon the presure differential of the atmosphere the the lower pressure resulting from higher velocity and also from the slight vacuum affect created by an airbox's restriction. The greater the airbox's restriction the greater the pressure differential and the more gas is pushed through the carb.

On my bike I have had none of the symtoms of richness that you described. In fact my exhaust has was a nice light/ medium brown. No sign at the tail pipe of things being too rich.

In fact I was even thinking about a larger main after screwing around with the leaner settings. (But just like you mentioned, it is so hard to tell if the carburation on the main is correct. Since you only have a split second and are usually going balls out).

So my recommendation to you is to go without the lid, and you might find that things work perfectly.

Don't worry about not getting back to me. Sometimes with jetting the only way to get things right is to make them wrong. If anything I confirmed that the jetting is not too rich. And as for me going up a size on the main. A lot of riding here is So Cal is at altitude. So may be here by the coast on a cold dry night things should be lean so that they are correct in the mountains.

Hope that helps. Let me know if getting rid of the cover helps.


Hi guys, I am new to all of this. My brother and I have just purchased 00 WR's. We both seem to have the high idle thing going on. The dealer removed the exhaust tube and trimmed the throttle stop. Now I am questioning there ability. Any input and further recomendations would be great. Thanks. John from Seattle.

Many people have had the dreaded high idle problem.

The correct fix is to go with a richer pilot jet. Stock is 42.

The quick fix to get the bike to idle propertly is to screw out the pilot screw until things idle properly. Maybe 3 turns or so.

This can be done with a short screw driver. I bought this little screwdriver tool from the dealer that makes it easier.

This will atleast enable you to break in the bike without it always racing.

When you say the dealer removed the exhaust tube. Do you mean the baffle?


John, yes I mean the baffle. I called them today about the fast idle and they seemed clueless. I did not tell them all the knowledge I am getting from you guys. They said they would put it back on the gas analyser and see what's up. I will adjust the pilot and then change to a larger p.j. after break in. Is this what you did? Thanks for your help.

I got my bike Dec 29th. I was probably one of the first to get their bikes so the high idle problem threw me for a loop.

I couldn't figure out why the idle would remain high even though the carb linkage clearly made clean contact with the throttle stop when the carb was closed.

I was convinced that there was something broken in the carb. So I took it back to the dealership.

They reported to me that they turned out the idle screw about 3 - 3.5 turns. This is with a stock bike. I rode it serveral times and the bike carburated fine. No problems.

Then I made all of the following mods at the same time.

1) YZ timing

2) DSP pipe and tapered header

3) Airbox cover removed

4) 48 pilot jet 180 main and two turns out. (I kept the stock needle and position)

The bike works flawlessly. The power difference was incredible. Almost like adding an extra 100cc or something like that. It also changed the nature of the bike from and freindly XR type of powerband. To more like the instant throttle response of a well tuned superbike.

So as for your situation. I have no experience with partial mods.

My best guess would be to go with a 45 or 48 pilot if you remove the cover with the baffle out and a 175 main. I tried a 45 pilot and it ran like crap. So it may be pretty clear to you which way to go.

I will say based upon another persons experience is that removing the air filter cover may have a huge impact on the jetting that is appropriate. So make sure the cover is off.

Good luck


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