07 Wr450 Stock Jetting

12 replies to this topic

Posted December 09, 2008 - 12:02 AM


I have a 07 wr450 and it seems like it is running a little lean. It is block stock and I know Yamaha probably sets these bikes up to run as lean as possible because of the smog standards so we can get a green sticker here in Calif.
Does any one know if I should go to a bigger main jet or change my needle settings to richen it up a bit?

  • desdave

Posted December 09, 2008 - 05:45 AM


When I bought my 08 I had the dealer install the gytr ais removal kit. It comes with a larger main, pilot and adjustable needle. It runs perfectly, and I haven't been into the carb since. The kit is like $45. Stock the main and pilot are lean, and it has a none adjustable needle.

  • timoyz1

Posted December 09, 2008 - 12:42 PM


Yes they are lean from the factory. I ran race gas which eliminated the detonation, but it would still overheat at times. Finally I bought a JD Jet Kit, and that did the trick. I can now run 87 octane in emergencies with no problems. I would shoot you the numbers of jets I am running, but I don't have that info with me. Like desdave says, the stock needle has no adjustment on it, so you will be stuck with what you got.

  • JSanfilippo

Posted December 09, 2008 - 01:59 PM


When my bike was stock, it actually didn't run too bad with the stock jetting. It had that "hollow" lean jetting pull but there were no stumbles or bogs.

For a stock bike in cold weather I'd bump the main up one to a 165 main jet with an adjustable needle. The stock pilot is actually ok (and I know some people who run the stock pilot jet on their modded bikes successfully) just get an adjustable aftermarket fuelscrew so you can tune it.

  • Deserthound

Posted December 09, 2008 - 02:04 PM


I also installed the GYTR AIS removal kit and did all the other free mods plus a Pro Moto Billet exhaust tip when I bought my 07. I found that the pilot and main that came with the kit (50/175) were way to rich so I changed to a 48/170 combo and that works great for me. Hope this helps.

  • snaggletooth

Posted December 09, 2008 - 04:47 PM


Welcome aboard BOSSRIGGER. If you don't have one of these or a new pipe on the way let me know, I'll send it to you for free. Now you will have the cash for the JD jet kit, it's a must to re-jet! It's Christmas time and I'm feeling merry, S/T.
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  • desdave

Posted December 10, 2008 - 07:06 AM


Ya know, just to raise some controversy, it seems that many on here, including me, were able to dial in their jetting without the $75 JD kit. I seem to read just as many posts from those that weren't able to make it work as those that did. Also, if your bike is not jetted correctly (new, stock lean etc), and you go straight to the JD kit, it should be better for sure, but I bet you could have achieved the same results with the yamaha needle, main and pilot with settings that others in your area (altitude) are using successfully. The only thing that is unique to his kit is the multi taper needle, but my stock YZ needle that is adjustable seems to work just fine. GYTR ais removal kit with jets/needle for $43 vice JD kit with just jets for $75.

  • JSanfilippo

Posted December 10, 2008 - 06:09 PM


Ya know, just to raise some controversy, it seems that many on here, including me, were able to dial in their jetting without the $75 JD kit. I seem to read just as many posts from those that weren't able to make it work as those that did.

I did the JD kit because I didn't want to hassle with tuning (carb access). You literally drop it in per the instructions and its ready to roll.

Knowing what I know now about what works and don't work in these bikes, I'd just buy the jets I need individually and save $50.

  • psmith85

Posted December 11, 2008 - 05:33 PM


I have an 06WR and 08 YZF. I am jetting my WR very close to what I did with the YZF. I upped the main jet 5 sizes. Before you freak out, try it. The motor will take alot more fuel than we think. I changed the needle in the YZF and will be putting the 08 YZF needle into the 06WR. I expect the results to be just fine.

  • JSanfilippo

Posted December 11, 2008 - 06:41 PM


What needle are you running? ^


Posted December 12, 2008 - 09:32 PM


Thanks for the info. I will be trying the 170 main and the 48 pilot tomorrow and will let you know if it works. I think it will from all the other advice I got from every one. So, thanks to all that gave me advice

  • BajaFool

Posted December 13, 2008 - 05:41 PM


I jetted my 2006 and 2008 WR450F's to the 2004 WR450F specs. They run very well, get great gas mileage and work from sea level to at least 5,200 ft. The 2004 WR450F specs are: #165 MJ, #45 PJ, OBDWR-4 needle and 1 3/4 - 2 turns on the fuel/air adjustment. Leave all of the other carb settings on your 2008 stock, except the fuel/air adjustment.

  • bruceal

Posted December 19, 2008 - 05:37 AM


I want to jet my 2007 wr450f does anyone have some good instructions or a manual for doing this? Also, which jetting kit is best?

Thanks, Bruce


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