05' 450 LEAN!!!! jetting.....anyone else?

10 replies to this topic
  • Boonie

Posted December 22, 2004 - 11:58 AM


My opinion of Yamaha, I'm sad to say, has dropped a notch. Here is what I've experienced so far with my 05' WRF 450:

1) Paid cash from dealer, got home and drooled over my new ride.

2) One week later, followed the manual to the tee and broke it in for just over
an hour. Started out idling OK but an hour later would not idle steady. Kind
of "surged" between too high and too low idle. Fiddling with the idle
adjustment didn't fix the problem......concern sets in. At break in, I had replaced the throttle stop with a YZF unit and snipped the gray wire. Nothing else. I should also mention that the power was decent on accleration with no noticable dead spots

3) changed oil and filter when I got home.

4) Fired it up a few times over the next week to see if rough idle persisted. At
initial firing, it idles fine the first minute but as it warms up and I putt
around the driveway(couple minutes later) the idle races too high or too
low like before. When I chop the throttle, the engine wants to race and
not return to low idle without applying the brakes(1st gear) when brakes
are applied, it idles down.

5) Since I bought the bike from a Yamaha dealer who is more marine(boat)
oriented, I took it to a different dealer who is all bike. They've been good
to me in the past and I trust their expertise. I said "for a brand new bike
it sure won't idle....somethings not right. Please ride it for 5 minutes and
see if you notice what I do. See if you can pinpoint anything."

At this point, I mentioned this should be a warranty issue shouldn't it? The mechanic said he would take a look but that I still had to signature the work where potential labor/parts costs could be involved if they found something otherwise. I understand their thinking as they are covering themselves but I mentioned it's pretty hard for it to be "something else" with one hour on the bike. He agreed and said he'd call me if there was a conflict.

He rode it and noticed what I did.....even performed a leak test(it passed) he agreed a warranty claim was in order and called headquarters. They nixed it on the grounds that all the 05's come lean to pass 50 state emmissions. What we are seeing is simply a case of lean jetting.

So, the mechanic(and headquarters) suggested a jet kit. I agreed since I don't want to detonate a new engine with lean jetting. They will also remove the baffle at the time of jetting. We went JD but alas....the company ran out of kits so we are on back order for a week. When I got home, I re-read the 30 day warranty and near the end it reads "warranty does not cover carburaetor". Swell!

In the end, I will have to shell out a couple hundred bucks for the kit and labor. Is this right? I new the bikes came lean with the AIS and all but I didn't figure so lean that the bike wouldn't idle correctly. I guess the jet kit will tell the story but I'm curious if any of you new 05' owners have had a similiar experience?

I'm having the dealer jet it because I'm not good at tearing into the newer carbs, they have the tools to do it right and if something's off they will work until it's corrected.

Lastly, what would you do if the kit doesn't fix the problem? Any other troubleshooting to consider?

Wish me luck!

  • RichBaker

Posted December 22, 2004 - 12:08 PM


Cancel the JD kit, get a pilot jet 2 steps richer, go to a 162 or richer main and get an adjustable needle, 04 WR is a good choice.
You can install these in about an hour, and won't cost more than ~40 bucks....that's what I did with my 03. :cry:

  • jerryls

Posted December 22, 2004 - 01:03 PM


they have the tools to do it right and if something's off they will work until it's corrected.

The only tools you'll need to change the jets and needle are a couple screwdrivers and an allen head wrench. Buy the JD kit from the TT store for the best price. Get an adjustable fuel screw too.

I know I was intimidated the first time I dived into the carb about a year ago. Did I screw up the jetting a couple times? Of course. But with trial and error (and lots of advice from here) I now have a pretty good idea of what jets and which needle to use for specific temperatures and elevations, and most importantly, to get the best engine performance. You can't imagine how much better the WR runs when the jetting is perfect.

Now go order the JD kit and go play around with your jetting. You might accidentally enjoy it :cry:

  • ovrrdrive

Posted December 22, 2004 - 02:01 PM


I say spend $20 and get a small assortment of PJ's and MJ's from the TT store and change them yourself.

It's a simple process that you really shouldn't mind doing...

It will be good practice for you.

  • Indy_WR450

Posted December 22, 2004 - 02:41 PM


Just get the JD kit you cant buy his triple taper needles anywhere! They are worth every penny! :cry:

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  • mtrablue

Posted December 23, 2004 - 10:50 AM


lean wr jetting is one of the most discussed subjests in this forum. we've all been there. you've got a new model. your going to have your issues also.

small steps. did you remove the small cover over the pilot fuel screw? this screw has a big effect on idle mixture. make sure this has been done. if you have to back the screw out more than three turns from all the way in, go to a bigger pilot jet. be careful, if you remove the pilot fuel screw, there is a tiny washer and o ring in there that like to fall out and dissapear on the garage floor.

the JD needles are good stuff, i use 'em. i was ,however, a little disappointed i had to pay for all the main jets i'll never use. your needle only has one clip position. at the very least, get an '04 wr or yz needle. i don't know if the '05 yz is the same as the '04 or not.

  • Boonie

Posted December 23, 2004 - 03:36 PM



I'm with ya on the small steps. The mechanic did fiddle with the air/fuel mixture screw and did not cure the idle issue. Perhaps indeed a bigger pilot jet is in order.

I'm a little confused as to the suggestion of picking up an 04' YZ or WR needle if the JD kit comes with needles.......those JD needles are adjustable aren't they?

As to the other suggestions of doing it myself; believe me, I'm tempted but I also have this lingering suspicion of "something else" wrong that the kit may not fix. If that's the case then I have the argument that if a dealer couldn't fix the jetting then there damn site better be a warranty claim somewhere. If the JD kit cures the problem, then I know at least I now have a solid bike.

This whole thing still chaps my ass though. I had an 03' WRF250 that was spot on for jetting......never touched it. The big change is just a dome scratcher for me.

  • Beef

Posted December 23, 2004 - 04:25 PM


Why doesn't Yamaha come out with a WRZ450F? :cry:

I Mean, what's this crap. You either have to go with a YZ and get a perfectly setup bike, sans the tranny, lights, kickstand and electric start...or go with a #$%!'ed up WR, and have to do a bunch of stuff to it to get it to run right. :cry:

Where's the middle ground? I'm looking at buying a new bike here in a couple months, and I'd pay an extra hundred bucks on top of the WR price, just to get a YZ with the kickstand, spark arrestor, lighting and electric start, call it a WRZ or something. :cry:

I mean, where is Yamaha's head? How many people on this forum would buy my WRZ over a straight WR? Everybody but the Californians I'm guessing. Someone at Yamaha needs to fire their marketing staff, and start over. :cry:

  • Indy_WR450

Posted December 23, 2004 - 04:48 PM


You need a 48 pilot and the JD kit needles have 7 positions. :cry:

  • mtrablue

Posted December 24, 2004 - 08:57 AM


the only reason i said anything about the wr/yz needle was that it (they) are cheaper and have multiple grooves for adjustment. there is no doubt that the JD needles are a better product. the biggest thing you notice with them is how smooth the power seems to be. that may not mean much to some, but for me thats important. have a good christmas.

  • HarveyMushman

Posted December 24, 2004 - 09:10 AM


For what it's worth, before I ever rode the bike I installed a 170 main and a 50 pilot, a adjustable fuel screw set at 1.75 turns out. I left the stock needle alone mostly because I wanted to RIDE! I'm at sea level and the bike runs clean and strong, starts right, no backfiring or any issues. After I finish break in and start to run the bike harder I may try the JD needles to see if there is more there.

It's at least 70 degrees in SD today, wish I could ride.

Merry Christmas everybody!!


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