WR to YZ timing, part numbers and costs.

I am planning on retiming my 1999 WR400 from WR to YZ timing, and removing the octopus. I am running from sea level to ~3000 ft, mostly desert, dunes, and MX. I run a Vortip insert in the stock exhaust, and have a Keintech Vortex airbox. (makes it REALLY easy to change filters. 4 dzus and pull it out). I am going to go buy all the parts I need to get the jetting in the ballpark. I don't have the manual in front of me (my bike is 150 miles away, at home. I am at school), and would like the part numbers to verify that I am getting the correct parts, as it has been rumoured that they are listed incorrectly in the Yamaha microfisces, as well as jetting suggestions. Any idea how much this stuff will cost? Can I deoctopus later and save my money up for the last two on the list, or do I need to do it at the same time as the YZ timing?

I was going to buy:

178 and 180 main jets, and try to run the 180

DVP needle, in clip #4 from the top

48 pilot jet

pilot air jet #100

YZ start jet #65

Is this everything I need, and does it sound about right? I am trying to do this all at once (probably not the best idea, but hey) and from what I have read this sounds like a close setup. Thanks a bunch.

Also, in the YZ timing instructions, it says it is not necessary to remove the radiators to take the valve cover off. Do I need to drain the coolant, or can I just pull the cover?

[This message has been edited by ButtonFly (edited 02-20-2001).]


you have a 62 starter jet as standard & i believe clarke mason the authority on this change has now gone back from the 65 to 60.

you have a 62, i have a 62, it doesn't make a discernable difference.

you can go to YZ timing without de octopussing. i did & didn't touch the jetting which was 172. if you have a 168 fitted buy a 175 & 180 that will cover it.

you need only really get the 100 pilot air jet. but don't forget that you will need three 'bungs' to block off tubes exiting; one from the inlet manifold at the head & one or two on the carb.

in addition to clarkes comments i would just add that you should zip tie the inlet camwheel to the chain. that way no matter how much pushing & shoving you do, you know that it's 12 pins you're trying to get to.

you'll need a torque wrench don't forget.

no need to touch any of the coolant system at all, the cam cover will come off fine.



I thought it was two vacum plugs on the carb and the vacum port on the intake manifold was where the hot start would get routed to?

My instructions and bike are at home, but I'll check tonight after work.



86TT225, 99WR, WR timing, throttle stop trimmed, air box lid removed, White Bros head pipe, silencer and air filter. Odometer and headlight removed. Moose hand and mud guards. YZ stock tank and IMS seat. Renthal Jimmy Button "highs" and Renthal Soft half waffle grips. AMA, SETRA.

quite right bill!

by the way buttofly, read my thread on snap & 3/4 throttle response. try & buy a pilot air jet-screw. this will turn out to No 100. i'm now recommending a No 125. you can turn the screw to be any number you want. IT IS THAT SIMPLE.


[This message has been edited by Taffy (edited 02-21-2001).]

I just ordered it. Sorry, I forgot to ask how much it was (money is no object, right?). You need the screw and a spring, apparently there is only one size/type.

Sudco 323-728-5407

Screw: 021-230

Spring: 021-235

Carb Parts 216-524-1599

Screw: 1014-817-2000

Spring: 16052-KM4-0040

Keihin (probably doesn’t sell them but…) 262-860-6000

(Carb Parts PNs are same as Keihin’s).

Okay, once I have this pilot air jet/screw, where does it go? :) Simple enough huh? Bear with me, my bike and manual are at home, and I am trying to get all this togethor to go home and change it all in one night...

Is it externally adjustable? Or do you still have to pull parts off the carb?


Go to the technical section and print the De-octopuss instructions written by Clark. I would and did get all of the jets he advised. The #100PAJ and the #65 start jet. Also the DVP needle. Clark has more testing time than I have miles on my bike. He and James Dean are regarded as the resident experts, although there are several people that have a good handle on jetting here.

I'm using the 175MJ, 45PJ, DVP#4, not sure where the fuel screw is. I have WR timing. I've also only riden the bike in my neighborhood, but it did seems to pull hard at all throttle positions, wheelies at will and no bogging. Can't await to get out and put some "dirt" time on her :) I ride 500-1500' in Pennsylvania. You can see my bikes mods in my signature.

The PAJ is not externally adjustable, it's located under the air horn. The start jet is in the bowl.

Cost not sure, I had all of this from last summer. I do know that Sudco is about half of the dealer cost. I needed a PJ and the local dealer couldn't help (long story) but a fellow TT'er (thanks Brian Meadows :D) came to the rescue by purchasing one from his dealer in California and he's sending to me ($10) Sudco was $4.80, but they have $20 minimum order.



86TT225, 99WR, WR timing, throttle stop trimmed, air box lid removed, White Bros head pipe, silencer and air filter. Odometer and headlight removed. Moose hand and mud guards. YZ stock tank and IMS seat. Renthal Jimmy Button "highs" and Renthal Soft half waffle grips. AMA, SETRA.

[This message has been edited by Bill (edited 02-21-2001).]

Originally posted by ButtonFly:

Okay, once I have this pilot air jet/screw, where does it go?


They’re calling it an air screw, actually, and it replaces your Pilot Air Jet.

This, of course, is right next to your Main Air Jet. :)

[This message has been edited by Hick (edited 02-21-2001).]

Originally posted by Hick:

This, of course, is right next to your Main Air Jet.

Sorry, just trying to be funny.

I believe it is to the LEFT of the Main Air Jet.

Okay, okay, the MAJ is in the carb inlet, or bell, and is obscured by the plastic air filter joint. You have to remove this joint, held on by two bolts, to get at the air jets. To adjust the air screw that replaces the fixed PAJ you I was told you will still have to remove the air filter joint, but you may be able to get a screwdriver into the passage in the joint that feeds it. Either way the carb or airbox needs to come off.

I currently am running a 175 MJ, stock everything else (in the carb).

I will run

62 starter jet (stock)

Either #100 pilot air jet or Taffy's screw.

48 pilot jet

DVP needle, 4th clip from top.

I am under the impression that I can run YZ timing, deoctopussed, with this jetting. Correct? I don't need the #65 start jet?

Does this all sound right?

BTW Taffy, read your thread, does anybody have a phone number or part number for the part? Just ring up Sudco and start asking? $10 right?

Also, is it worth my fussing with the APJ like you guys discussed by putting shims under the diaphragm? Or is this an excercise in your personal quests for perfection :) I too would like to get rid of some of the bog off bottom, but not at the expense of cutting up my FCR. Can't afford to buy parts I mess up. Are they any dangers to putting the shim in the APJ?

Thank you so much for your time.


i don't feel you should experiment unless you're happy to learn the hard way all the time. better that JD et al post you some settings & you just describe what's going on.

the starter jet has proven for most of us to be irrelevant. clarke for instance, twist's his wrist twice & suddenly it's alive & throbbing!!!

remember that the pilot air jet is an air bleed system that should be matched to a pilot jet. i have & you will be given the infomation on how many turns out represent a No 100 PAJ etc etc. so don't be too worried. the point is, i'm onto something & i would have got through 5 PAJ's last week instead i got through the one!

the PAJ-SCREW may be available from sudco, my guess is that JD will let all you yanks know in the next 48 hours. in england it was £6 ($10).

another thing you will find is that you end up with a long hollow tube with a bolt through it. i cut the bolt to a more appealing length.


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