'05 WR450 Tuning - Uncorking, Jetting


23 replies to this topic
  • wr450_bob

Posted November 16, 2004 - 07:43 PM

#1

I have finished my first break-in ride on my '05 wr450 (CA) and am ready to open it up. I have already removed the smaller inner tube inside the baffle and the noise and power is about the same. I will remove the whole baffle assembly leaving only the spark arrestor. I will also pull the gray wire, unplug the airbox and will install an adjustable fuel mixture screw. The throttle stop has already been replaced.

My question is with regards to jetting: With the above changes, will adjusting the fuel mixture screw be enough to insure the engine doesn't run lean? I will check the plug but wanted to get a baseline to start. The dealer says I don't need to rejet but am not 100% convinced he is correct. Please help if you have gone thru this on a '05. Thanks.

Per Yamaha manual:
main jet 165, pilot jet 45

  • Texas4play

Posted November 16, 2004 - 08:38 PM

#2

It's going to be lean and the best upgrade for your carb is the JD jetting kit (TT shop). He has all the parts and instructions you need to make it run very well. Mine went much improved.

  • wr450_bob

Posted November 16, 2004 - 09:29 PM

#3

Thanks for the info. The '05 stock needle (per manual) is not adjustable - only one groove. Will the stadard 5 groove JD needle work? If so, I'll get the JD kit, but if it doesn't ship right away, will the wr450 be too lean to run uncorked with stock jetting or will to just not be tuned ideally? I'm planning on a 2 day trip next week and may not have the time in rejet unless it arrives before this weekend. Also, can I just rotate the carb to access the needle or did you have to remove the carb? My xr400 was not so easy. Thanks

  • gimprvr

Posted November 16, 2004 - 10:14 PM

#4

I've got an 04 and I ran mine without the buttplug several rides without issue, in fact the bike ran great. At least I thought it did until I picked up a pipe and JD kit. No it runs about 4.5 times better than great. I made both chnages at the same time but I would put my money on the JD kit before the pipe.

BTW you can just rotate the carb to get to the needle on the 04, very easy and forward install :cry:

  • RichBaker

Posted November 17, 2004 - 11:55 AM

#5

Thanks for the info. The '05 stock needle (per manual) is not adjustable - only one groove. Will the stadard 5 groove JD needle work? If so, I'll get the JD kit, but if it doesn't ship right away, will the wr450 be too lean to run uncorked with stock jetting or will to just not be tuned ideally? I'm planning on a 2 day trip next week and may not have the time in rejet unless it arrives before this weekend. Also, can I just rotate the carb to access the needle or did you have to remove the carb? My xr400 was not so easy. Thanks


You can shim the needle with washers... I have the 04 WR needle in my 03, it works quite nicely and has 7 grooves. I had the carb out anyways, but I don't think you can rotate it enough to get to the needle.

  • wr450_bob

Posted November 17, 2004 - 07:29 PM

#6

I ordered the JD kit last night. The stock restriction is so great I think it would have to be lean when uncorking with the stock jetting. Thanks for everybody's help.

  • YamahaWR450FMike

Posted November 17, 2004 - 11:28 PM

#7

don't know what all the talk is about re-jetting. never had to touch mine on my 04 WR450 runs strong and tons of power with the stock jetting

  • cruise

Posted November 17, 2004 - 11:45 PM

#8

i havent had mine jetted it runs fine
no backfireing unless its ran out of fuel
[thank god for the reserve].but i havent
taken out the baffel as the back of my
exaust is welded on

  • chipwich

Posted November 18, 2004 - 07:20 AM

#9

i think it depends on how yamaha jetted the bike and of course where you live. my friend with an '03 had to lean his quite a bit, but the jetting he ended up with is the same as my '04 came stock. so, his theory is that yamaha jetted the '04 to run unplugged and the '03 run plugged.

  • Texas4play

Posted November 18, 2004 - 09:29 AM

#10

All I know is ... the greener it is, the leaner it is!

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  • Maddog542

Posted November 18, 2004 - 02:44 PM

#11

I was able to get away with all of the other mods with stock jetting UNTIL.... I opened the airbox up. That one will likely give you the bog from hell. Leave it alone until you're ready to rejet would be my suggestion. JD advised me to raise the stock needle 1 position, and jet 2 sizes higher for the airbox mod. I did this and the bike runs great. I'm not sure what you do on the 2005 if the needle is not adjustable, but it will likely take 2 sizes up on the main jet.

  • wr450_bob

Posted November 18, 2004 - 07:27 PM

#12

I ordered the JD kit and plan on bumping up the pilot and main by at least a point or two or will see what JD recommends. I don't see how the bike could properly run when the stock baffle is restricted to about 5/8" in diameter. I'll post my results on Sunday if I receive my jetting kit on Friday. If you don't hear from me it probably means one of my neighbors turned me in for zipping up and down the street. Thanks for everyones help.

  • James_Dean

Posted November 19, 2004 - 07:43 PM

#13

I have installed the kit in the '05 WR450 and, yes, it will solve the lean jetting issues for new model.

See- http://www.thumperta...794#post1512794

Thanks,
James

  • wr450_bob

Posted November 19, 2004 - 07:59 PM

#14

Thanks James. I'll install the JD kit tomorrow. Ordered it Wed night and it arrived today. Great service. I mainly ride in the so cal desert and Gorman so will use the 70 main and the needle in the third position (full baffle removed) I guess if I were to get a FMF Q the 3rd position would still be ok? or if I get the FMF power core 4 the 4th position? Thanks, Bob

  • James_Dean

Posted November 19, 2004 - 09:15 PM

#15

Yes, the settings you suggested should be good with #170 main jet and fuel screw out approx. 1 3/4 - 2 1/4 turns.

Thanks,
James

  • Texas4play

Posted November 19, 2004 - 09:18 PM

#16

Looks like Yamaha took care of the air box mod on the '05. At least on top. Mine was already open and breathing from the factory. Course, this does make sense if you're objective is green sticker (factory speaking). Lean out the fuel - shove in the air......see how clean it is !!!

  • wr450_bob

Posted November 20, 2004 - 03:55 PM

#17

James,
I put the 170 main with the blue needle in the 4th position. Full baffle removed, airbox plug yanked, yz stop and gray wire pulled. The bike runs great and the plug was nice and tan but the "Scotts" mixture screw doesn't change idle much. There is a slight drop when the screw is closed but the bike still runs. Between 1/4 and 2 turns the idle remains the same. Idle is good and the bike runs great. Good low, mid and high acceleration and no backfire or stumble. Is my setup ok? Thanks, Bob

  • fsott

Posted November 20, 2004 - 09:51 PM

#18

Are you saying that if you have an 05 you don't have to modify the air box.

  • MXrider101

Posted November 20, 2004 - 10:49 PM

#19

Looks like Yamaha took care of the air box mod on the '05. At least on top. Mine was already open and breathing from the factory. Course, this does make sense if you're objective is green sticker (factory speaking). Lean out the fuel - shove in the air......see how clean it is !!!


really? i think thats y me and my dad couldnt find the air box boot thing. we were trying to find it so we could take it out but we couldnt find it. did they not put it in the 05 models?

  • wr450_bob

Posted November 21, 2004 - 08:01 AM

#20

The california 05 has a restrictive insert right behind the battery. It had two square windows with the center section closed. Maybe this in only on CA models? To remove, note the bracket to hold the battery strap holds the insert in place. To remove, put a screwdriver behind the battery bracket and carefully pry in out. It pops right out if you pry from the front side. If you pry from the back it won't come out.




 
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