Stock jetting ???

I just bought a new '04 WR450 2 weeks ago. I am happy with the bike, but the jetting seems lean because it stumbles off idle and pops a lot on decel. So I spend an hour getting the float bowl off without removing the carb so I can throw a 45 in and check the main jet size. Well, the "stock" jets are a 45 and a 165, not at all what the dealer told me they would be. So now I'm wondering if the bike I bought is not so new after all. I mean the rubber was obviously new and other than being a bit dirty the rest of the bike looked new, but there were a couple of scuffs on the plastic and it was delivered with the baffle already removed. Is there any chance these are the factory installed jets? If not, should I make a stink to the dealer that the bike could not have been new if someone already rejetted it? I've bought two other bikes from this dealer and I'd like to believe he wouldn't pull something like this, but as popular as the WR450's are, I now think it strange they would still have one when 05's are on the floor. They also did not have an '04 manual to give me with the bike and had to order one. Hmmm... :cry:


Couple of questions. The dirt you said was on it. Was it dust or dirty water marks from the rain, or was it "gone riding" dirt that didn't wash off? Did it still have all the "warning stickers" on it? You may have gotten a demo bike that had all the free mods plus the jetting done, during which time they lost the manual.

my 04 WR450 has stock jetting and runs pretty good it has 600 miles on it now and I'm happy with the stock jetting so far

Did you take the entire bowl off or just the cap that covers the jets?

I can't answer your question as to if the bike has been rejetted, but I suppose its possible the jets got mixed up from the factory when they built it. Unlikely, but possible.

Dealing with the problem at hand though, did you adjust the fuel screw before you attempted a rejet?

With the 45 in there, I would think you should be ok until it gets really cold where you ride. Make sure the fuel screw id correctly adjusted, and if its still lean it may just be time for a 48 pj.

As I believe a lot of bikes from the dealer are jetted lean, mine was and I have heard others say the same. Is this a canadian model or USA model ? The jetting is different on each bike. If you plan to continue running it uncorked then you will need to adjust the jetting. The standard for my 03 was 45pj and 150mj but came to me with a 43pj and 155mj, go figure. On Canadian model bikes all jetting numbers are bigger. I think I would go with the idea the dealer did free mods on the bike before selling it, which was something dealers sometime did.

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