I searched and could not find another topic on this so here goes;  I just bought a brand new WR250FB 2012.   It is a USA bike.   I got a mod list to try to get some power out of the thing.  The list and the instructions were for a 2008 model.   Most stuff looks the same, but the wires are not behind the left side cover, they are under the seat, and there is no grey (gray) wire.   Any idea if there are differences I need to know about between the 08 mods and the 2012 that I have?

Thanks everybody!

I used to have a 2009 WR-250FY (the Y = 2009 Yamaha motorcycle), and my CDI unit and the gray wire were under the left side cover, next to the coolant reservoir.

The parts catalogue on the www.yamaha-motor.com website shows the CDI unit for a WR-250FB (the letter B = 2012 Yamaha motorcycle) in the same location, and the part number for the CDI unit is the same.

All the same on a 2008 WR-250FX, too.
You sure you got the correct wire?

Well, maybe I was looking under the wrong cover.   Now I feel stupid.   Thanks for the reply and the info, I'll go check it out.

Cool.

Here's a pic of the 2009 model I owned (and regret selling).
The CDI unit is just in front of the white plastic coolant reservoir in this pic:

I see it, and I believe you!  I actually looked under the wrong side.   Did you do all the mods to get the power up to more of a YZ level ride?  

Why did you sell it?

Sure.
Got a few minutes?  

Here's what I did to uncork my WR-250FY:

Yamaha GYTR AIS Removal Kit.
Comes with all of the parts needed to remove the air injection parts, a jet kit to rejet the carb, and instructions on how to do all of those "free mods" you've read about, as well as how to install the jet kit.
It even shows you exactly where the infamous gtay wire is located with a picture on the instructions sheet.
Well worth it, and my WR ran very well, indeed, after installing this kit.
Specifically, once this kit is installed, your bike will be have the airbox snorkels removed, the air injection parts removed, the throttle stop replaced with a shorter one to allow full throttle, the muffler outlet (the rediculously tiny one known as the "pea shooter", not the spark arrester portion) removed, the gray wire disconnected, and  carburetor rejetted so the bike will run well in it's new uncorked state.

FMF Powerbomb Header and Q Muffler.
After the AIS removal kit was installed, I had the feeling that I was riding a good-running bike that still had a plugged-up exhaust system.
Boy, was that notion correct because when I installed the FMF exhaust system, the bike gained noticable power and torque across the whole rev range, and the most noticable gain was at the low end.

I did not change the exhaust camshaft timing to "YZ specs." as I felt the bike ran perfectly for me.

With the above mods, I rode the bike practically every weekend for 2 years, the only other changes being personal suspension and controls adjustments that I believe every rider should make for themselves.
The bike worked well out on the tight and often rocky trails of Connecticut - a great engine, and great rear suspension, and a great light-weight feel with high manoverability.
A very well-balanced bike.

Why did I sell it?
Because I screwed-up, basically.
No matter how great a bike is, I'll eventually start thinking about riding something else.
I envisioned getting a WR-450F and riding those same trails with mega-horsepower at my disposal, however, I saw a used 2009 Honda CRF-450X for sale before I saw a good WR-450F for sale.

I bought the CRF-450X, put it through CT. DMV inspection and got it registered for street use (required to ride on my local state forest trail loop), and started to use that as my weekend bike.
The 450 has tons of power and torque, and at first, i was basically punch-drunk with my newfound big man-sized bike.
I decided to sell the WR-250FY (CT. street title and all) to recoup the money spent to buy the Honda, and that was where I went wrong.
In hindsight, I should have kept the WR in storage until the day came where I finally decided that putting up with the considerably heavier feel of the CRF-450X on those tight trails would start to turn me off.
Well, that day came, and I sold the CRF-450X to a coworker just two weeks ago - CT. street title and all (a street titled dirt bike is not very common around here, especially a Japanese one where the Certificate of Origin says "This Vehicle Was Not Manufactured For Use On Public Streets, Roads, Or Highways". It takes money and effort to get around that part).

I rode that CRF-450X from the first weekend of December, 2011 up to July 23rd, 2012 - after not quite eight months I'd had my fill and decided the power of the 450 wasn't worth putting up with a bike that felt too big on the tighter trails, to the point of where there were certain trails I simply did not want to take since I knew it would feel as if I were piloting a locomotive down the trail.
The bottom line was the bike wasn't well balanced for me on those trails - plenty of power and the bike felt good on the faster sections of trail, but manouverability suffered on the vast majority of where I ride.
Bad move.

So, now I picked up a cherry 2002 WR-250FP just two weeks ago and I'm in the process of installing the parts required to put the bike through CT. DMV...

Edited by YZEtc, 13 August 2012 - 11:39 AM.

Well cool.  Glad you are back on board.   I was born in Connecticut.   I used to have a CRF450 2004 that I rode in the woods and the occasional motocross race in Oregon when I lived there for a few years.  I loved the power too, but was getting killed by the little bikes in the tight paths on hillsides.   Thought the 250 might be the ticket for me as well.   I was so depressed when the bike arrived and was so underpowered though.  Glad I discovered this forum, and thanks for your help and tips.  I will let you know how it all works out for me.   I too suspected the stock head pipe may be choked by the EPA, so I was checking out replacements.   There is one called the "Power bomb", got a little bubble in it, do you have any input to offer on it?

Yes, the FMF Powerbomb header is the one I used on my 2009 WR-250FY, along with an FMF Q muffler.
They give better performance without being loud.
But, as I wrote in my post above, you have to do all of the other mods I mentioned if you want your WR-250FB to run as you expect it to.
That's just how the bike is built because it comes in a power-reduced and restricted state (corked up).

Edited by YZEtc, 12 August 2012 - 03:42 PM.