JD jetting kit for WR250

[gsev]

Hello,

I just acquired an 03 WR250F that has really low hours and has set for some time. The engine is completely stock, the snorkel in the airbox is removed and the previous owner has removed the baffle from the exhaust. This weekend I will remove the grey wire from the ignition, check to see that it has a YZ throttle stop and do the "O" ring mod. The same mods that I did to my WR450.

The bike runs pretty good, starts great, but has a terrible bog off idle. I posted this on the jetting forum and William 1 gave me some good advice about the AP in the carb and leak jet size.

Would I be ahead to buy the JD jetting kit for the bike or buy appropriate individual jets? Is the JD kit worth the money? Does it come with appropriate leak jet?

Thanks

gsev

[Swede73]

JD kit is worth the money I think but it may not solve your problem. The JD kits secret is the needle and the way it tapers and James's instructions. The kit includes two needles and main jets. You will have to solve the problem of your AP not working properly to get rid of that bog. Have to make sure the AP is squirting. If it is squirting then it may not be enough and that's where the leak jet and oring mod come in. In order for the JD kit to work your bike needs to breathe properly. You have to open up the airbox more, not just snorkel. You have to replace the exhaust or drill holes in the front baffle with a long drill bit.

[vents]

Wow. this sounds remarkably like my experience. I just bought a super low hour '03 WR and it was scary the way it bogged . I can't speak to the JD kit , but stock the bike is simply way too lean . I installed a 42 pilot , 180 main, 55 leak jet and a YZf needle ( pt # ?? ) and it's running darn near perfect. My bike came with the baffle out of the exhaust so I added a GYTR insert and I'm loving it. I'm surprised and impressed with the performance and the bike is whisper quiet .

[ronbuell]

Guys, the secret to making it run is to replace the muffler. My '04 was the same way after the JD kit. Then I installed an Akrapovic pipe with spark arrestor screen. WOW what a difference....... its the muffler. Replace the stock unit.

[gsev]

Thanks for the information, I think I will try rejetting this weekend.

gsev

[Zacharydirt]

Sweed, i have an 07 and will be doing the jd jetting mod-i want performance out of the bike but not noise-i love how quiet the stocker is and need the spark arestor for forest riding. What is the recommendation in this case?

[Swede73]

I have an FMF Q4 and it's quiet and has all the performance and a SA. Since AMA and FIM are cracking down hard on noise I'm sure all of the major exhaust companies make performance quiet systems and any of them will out perform the stock WR exhaust. What you can do is look for a stock YZ exhaust that will fit your bike. It will be plenty quiet and the performance will be a lot better. You will have to get a SA end cap but there are lots of companies that make those at a descent price. Look for a used YZ unit on eBay or on the TT classifieds. I say what ever you can get the best deal on then get it. FMF and Pro Circuit both have the sales every now and then and that is when I got my system.

[hart]

Just did a jd jet kit.. I'm telling you that it will really help with the bog. the jet kit comes with the accelerator pump mod, including the leak jet change recommended. plus the normal jetting changes.. really transformed the bike. they really respond to questions about recommendations too. I really think your looking in the right direction with JD.