Jetting 00 WR400 with YZ timing?



7 replies to this topic
  • ScottyR

Posted May 26, 2000 - 06:47 AM

#1

I am sure someone has asked this before but I am really new to these 4 stroke monsters so please forgive this stupid question!! I have a Canadian WR400 with the stock pipe and I want to switch it to YZ timing. My local dealer is not really into dirt bikes and tells me I dont have to switch the jetting but other people say I have to. What do you guys recommend for a 2000 WR? DVP needles are hard to get so I am finding, is there an alternative? I ride at about 1000 ASL. What about removing the airbox lid? Does it make a big improvement? Thanks guys!! Scotty

  • James_Dean

Posted May 26, 2000 - 10:59 AM

#2

Canadian Eh? The needle should be a DRQ. You are in luck, DRQ is nearly the same as DVP, only 2 clips richer. ( DRQ#3 equals DVQ#5 ) The straight diameter is slightly leaner (Q vs. P). The only changes I would suggest is a #45 or #48 pilot jet and a bigger main such as 175-180 with the lid off.

**** Side note - The stock clip position DRQ#4 looks VERY rich (like DVP#6) and could be a source of plug fouling at 1/4 throttle. You may want to experiment with a leaner clip position.***

My needle taper evaluation is in progress for the '00WR and there will be more power at 3/4 throttle when the best one is found....

James Dean

[This message has been edited by James Dean (edited 05-26-2000).]

[This message has been edited by James Dean (edited 05-28-2000).]

  • RodH

Posted May 26, 2000 - 09:01 PM

#3

Scotty, you didn't say what pipe you are running ? And if it's the standard pipe then the jets that have been reccomended are way over the top. I think the Canadian pipe is the same as the Australian pipe, and they don't have a removable baffle and they are very restrictive. They flow the equivelent of an E-Series with 2 discs in, so a 180 main would be way too big. I have found that with 5 discs in the E-Series you can use the standard 165 main jet, but thats WR timing, only the air box snorkel removed and the Hawkins E-Series which has an internal diameter of 1 3/4" as opposed to 2" for the shorty E-Series. I was also running a 45 pilot, but this new high octane unleaded we have just got in Australia makes it run rich so, I have gone back to a 42 pilot, and 1 1/2 tunrs on the fuel screw. The 00 WR400 runs rich from standard, compared to the 98/99 WR that was on the lean side from factory, so you have to be very carefull with the advice from this list, as sometimes people give advice for 00 WR's and the jetting advice is applicable to the 99 model.
Don't turn the fuel screw out more than 2 turns as you risk decreasing spring pressure on it amd loosing it, if you need to go more then you should be increasing the pilot jet.




------------------
RodH Canberra, Australia<A HREF="http://www.400thumpers.oz-au.com" TARGET=_blank>
400 Thumpers Australia</A>
2000 WR400F See Photo's and Modifications

  • James_Dean

Posted May 27, 2000 - 07:58 AM

#4

RodH,
Thanks for adding your comments. The exhaust is an unknown factor.

I've been trying to get the most performance out of my US '00WR with stock exhaust, no baffle, airbox lid off, shortened throttle stop. Extensive testing is in progress.(500' elev and 60F)

-Pilot jets run have been 42, 45, 48, and 50. (45 looks best, 48 is rich past 1 turn)

-Main jets run have been 168, 172, 175, and no main jet at all! (rode 20 miles with no main jet, it accelerates good but doesn't rev and never fouled out) The 168 ran about the same with or without the airbox lid and snorkel, 172 and 175 ran best with no airbox lid.(the 180 was speculation from feedback on the forum)

-Needles, 6 needles are being tested with 3 tapers and 4 straight diameters. The increased taper needles give more power at 1/2 to 3/4 throttle(no airbox lid). The YZ426 uses more taper on the needle. The YZ/WR400 needles don't have enough taper, they are too fat at 1/2 to full throttle and run lean, less responsive in this range. Thus the main jet becomes less important. There is more power left untapped here. If someone was used to an open class 2-stroke they would be disappointed!(read me).

-Any feedback will help everyone. I know there is not one perfect combination for every configuration (exhaust, intake, altitude, temp, rider...), but there will be an improved setup that will fit most. With some basic guidelines, we could post it as a starting point. Clark has the '99 dialed for everything (except taper) and that is an important reference.

- I'm Power Hungry...

- Any more feedback? Anybody? (add your setup to the jetting section on the forum)

- pilot, needle, clip, main

Thanks
James Dean

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • ScottyR

Posted May 28, 2000 - 04:17 PM

#5

I am running the stock Canadian pipe. It is the one that you cant remove the baffle or modify. I have only had 2 strokes in the past and am kind of lost when it comes to these four strokes. I dont know where to start with this thing, the more posts I read the more I am confused. I appreciate any info you guys can give me. Thanks! Scotty

  • Kevin_in_New_Hampshire

Posted May 28, 2000 - 04:48 PM

#6

Scotty,
With time, you will get it, these 4 strokes. I know, I was there too. Just screw your engine up enough and then you get to figure it out!!


------------------
99 WR, all YZ mods, de-octopused, OEM YZ tank and seat, jetting by Clark.

  • Clark_Mason

Posted May 28, 2000 - 07:16 PM

#7

James

Sounds like you are trying to get me into a EVP needle?? After I get through with my pipe testing and bumping up to a 420 I will give it a try but not for a while too many projects at the moment and major stess at work for a month or so.

Clark

  • James_Dean

Posted May 31, 2000 - 09:03 PM

#8

Clark,
Yes you should try the EVP carb needle. (P/N 5BE-14916-EP) The profile matches the YZ426 jetting and it uses your best choice for straight diameter. Start 2 clips richer because the taper starts 4mm lower. This will have a cross-over effect.(lean/rich) The gain is at 1/2 to 3/4 throttle. Hopefully the clutch will handle the extra torque. (The 426 got a beefier clutch...)
At low altitudes and cool temps an FMP will have more boost yet. I expect that a multi-taper needle mixing DVP#4 and FMP#3 will cover a broad range with more torque. I will make one from a brass needle from Sudco and you can try it along with the EVP.
More will follow via e-mail

James Dean




 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.