05 WR450,Gray wire????

What exactly does the "Gray wire" do??? I have heard both that it is a rev limiter and something about a timing thingamabob, Can anyone confirm what it is, and Pro's and Con's of disconnecting it?

I have disconnected it but am concern about the engine turning over 14K RPM. I'm kinda a rookie and would hate to blow up my new motor.

I've removed the baffle plug from the exhaust , replaced the throttle limit screw with one from the YZ 450 (18mm)

I like performance but not at the cost of blowing up my machine....

Thanks guys...

Don't worry about it. At least on the '04, every bike outside of the US came with it cut from the factory. It changes the timing. I think it may slightly raise the rev limit, but not enough to worry about. As long as you don't play the 'bounce of the rev limiter dump the clutch and shower your buddies in mud' game too often, you will be fine. If you are a rookie, hitting the rev-limiter occasionally will likely be far more dangerous to you than to the bike. The only way to blow it up real good is to be high in the rev range and then drop down a gear.

That said, i generally short shift because i am not racing and going high rpm's for no reason is not that engine friendly.

I've heard that it maps in all the positions of your throttle. With the throttle stop in, you do not get full use of the throttle and that they did not "program for those positions". So, when you remove the throttle stop, there is a kind of a flat area around mid range. By disconnecting the gray wire, you get a yz map that advances the timing and is set up for the full range of the throttle. You could just keep reconnecting/disconnecting the wire to see what difference it makes.

You do not have to worry about blowing your engine if you control the throttle. If you consistently ride near the throttle limiter, you would more likely blow the engine irregardless of the gray wire. Besides, it is a WR450. You do not need to rev the engine to get the power.

As you do the free mods, you will notice that each mod is only subtly different. But togeather, they make a noticeable difference.

Here's what I got from Yamaha :

The CDI unit is the same for both YZ and WR models. The gray wire matches the ignition map to the WR and its shorter throttle stop to limit RPMs. This is done solely to allow the WR to meet drive-by sound restrictions. By swapping to the YZ throttle stop and disconnecting the gray wire, the WR can now access the YZ ignition maps that allow ignition timing that matches the wider throttle openings. There is no lower rev limiter, per se, in the WR CDI. The limitation comes from the stock WR not being able to have its throttle opened completely. Disconnecting the gray wire simply allows the CDI to use the YZ ignition curves that provide high RPM timing advance not available with the WR's stock setup. Besides meeting the noise restrictions, the thinking is that the WR being a trail bike, most riders won't miss that high RPM capability. And those that do, well, it's there if you want it. I'll be covering this and many of the other WR mods in an upcoming issue of Dirt Rider magazine.

You may want to give some homage to the 250F FAQ because it contains the same info. in this thread.

You may want to give some homage to the 250F FAQ because it contains the same info. in this thread.

Huh? Homage? Why? As I said in the 1st sentence I got it from Yamaha. In fact, my info came directly from a conversation I had with someone from Yamaha US. You assume I even read the 250F FAQ (didn't know one existed) and imply I might have stolen it from there when I clearly said otherwise. If the info was in this supposed FAQ, why didn't you post a pointer to it or do your own "homage" to it? I don't know what the point of your response above was, but I find it offensive that you would insinuate plagiarism on my part. Someone else might not see it that way, but I make a living writing about motorcycles and I don't appreciate your implication.

Well if it walks like a duck, and quacks like a duck!!!

I just talked to NASA and they told me the world is round, can I put it in your magazine. I did my own research.

Well if it walks like a duck, and quacks like a duck!!!

I just talked to NASA and they told me the world is round, can I put it in your magazine. I did my own research.

So tell me exactly why I should reference or credit a source I didn't even use or know about? FWIW, I did include this website in the source info in my article because it helped inspire me to do the story, but the info on the CDI came directly to me from a Yamaha engineer. I notice you also didn't take the time to include apointer to this FAQ in your wise a$$ reply. Guess it's just fun to take potshots without offering anything of value in the process.

:)www.thumperfaq.com

It's quite handy , or it was for me. :p

Yeah, but I haven't explored it too much because it's mostly for 250s and seems to cut off at 2003 models. Also, many of the links at the bottom of the pages don't work or lead back to threads in TT. Thanks for posting something useful, though. Oh, and you should see someone about that Ninja disease. Serious sh*t, IMHO. :)

I did not give any advise or critical info because I have dealt with individuals who blow their own horn such as you, and felt that your conceit spoke for it's self. I personally am tired of reading info that is inept at best, from so called experts who write in these rags. Your defense of your actions only show how cut-throat these rags are, by not giving proper credence to the hard work of others. If I did research such as you do in my past business, people would have died.

My personal experience with the media is they are a joke at best. Is this the magazine where fired New York Times writers go?

I did not give any advise or critical info because I have dealt with individuals who blow their own horn such as you, and felt that your conceit spoke for it's self. I personally am tired of reading info that is inept at best, from so called experts who write in these rags. Your defense of your actions only show how cut-throat these rags are, by not giving proper credence to the hard work of others. If I did research such as you do in my past business, people would have died.

My personal experience with the media is they are a joke at best. Is this the magazine where fired New York Times writers go?

You sure are making a lot of assumptions, don't you think? Is it fair to tar me with the same brush you have for others without knowing me or having read anything I've written? When warranted, I always credit my sources, but that isn't the case here. I didn't "steal" anything from in here. The idea of opening up the airbox came long before TT as did many other ways to modify a bike. I've been riding and racing motorcycles on and off-road since 1973, owned a custom Harley shop, and spent the last 12 years writing for motorcycle mags. Got a problem with the media? Fine. But don't let it blind you into making unwarranted attacks on someone you don't even know. :)

RADrick, jdd123 that's just the info I've been looking for. I just picked up the 05 wr450 and did the throttle stop, JD jed kit and the tail pipe restrictor but was really concerned about the grew wire thing. I did the grew wire on a 02 wr250 and had some jet work to try and figure out when I got into the higher rpms. Once I figured it out that bike was awsome but it took me some time to figure it out. Could you recommend a starting point if you had to do any thing in that area? I ride in Michigan mostly in the spring and fall and I,m in the 0-1000ft range and at an average of 65-80F. I'm still trying to learn more about the carb stuff and the manual is not real good in that area.

Does removing the grey wire affect the low end at all?

Great mag!!! One of the few that talk about trail and not tricks. :)

I remember reading a good description of the circuits in the 250f FAQ. The JD jet kit can give specifics.

I plan to do my bike when the temps warm up to 70+ here, since I bought the bike this Christmas when it was 10 degrees out.

There is a good description about setting the pilot circuit but my ear is not good enough and I haven't bought a tac yet. The dealer can adjust your pilot (fuel screw) using a machine that samples the exhaust.

For the needle circuit, you have to ride the bike. If it sputters and gurgles at 1/4 to 1/2 throttle, it is rich. If the bike runs hot and backfires then it is lean.

The main jet circuit (3/4 throttle and above), again has to be done while riding. You can use the color of a new plug method mentioned in the FAQ. The other way is to try different main jets. When wide open, a richer jet will cause the engine not to reach it's peak rpm. Another trick a mechanic mentioned was to pull the hot start at that circuit and see if the engine runs better. The hot start leans the bike. When trying to jet, I put masking tape with markings for full, 3/4, 1/2, and 1/4 on the housing so I know exactly which circuit is the major contributor.

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