2005 Wr450 Mods List

[mousemeat]

Here is my list of the mods needed to make your WR450 run properly. It focuses on the 2005 model but most is applicable to all 450 models. Any corrections, comments, clarifications etc are welcome. I hope that one of the mods will make this a sticky at some point.

1: Throttle Stop: When your US spec bike arrives, there is a screw that prevents the throttle from opening fully. You either need to cut it down so that there is 18.23mm of thread (not including the head), or order yourself a YZ450F throttle stop, part no 5JG-14591-00. Canadian, OZ and European spec bikes come with YZ throttle stops and do not have this problem. Do not simply remove the throttle stop, as this will cause your throttle to function improperly and can damage your engine.

2: Exhaust baffle: This is not required if you are going to add an aftermarket silencer. The stock exhaust baffle greatly restricts the bike, reducing power. Removing this baffle will increase the power, but will drastically increase the noise levels. If you are using the bike on closed MX courses or private land in a remote location, this should be fine, it's not going to be louder than any of the 4 stroke MX bikes out there. Removing the exhaust baffle requires removing the end cap from the silencer, taking the baffle out, and putting the end cap back on. On 2004 and earlier bikes if you are using the bike on public land or are concerned about noise you can either pick up a quiet exhaust insert for your stock silencer from www.promotobillet.com, www.quietiscool.com or get a GYT-R one from Yamaha. These aftermarket baffles will not work on the 2005's, but ProMotoBillet will have an insert for the '05's available next month.

3: Grey wire: With the exhaust opened up and full throttle range achieved, the ignition needs to be changed to YZ specs. Like the throttle stop, this only applies to US spec bikes. To change to YZ specs, you need to follow the instructions here: http://www.thumperfaq.com/gray_wire.htm

4: Removal of AIS: The '05 WR450F (but not the 250) is califronia green sticker legal. In order to achieve this, yamaha had to install a smog pump, also known as a bunch of goofy pipes that get in the way. This can cause lean jetting and backfire. There are two ways to remove this. 1) order the kit from TT member 'Lowedog' or plug up the holes with rubber plugs. This is discussed in this thread: https://www.thumpertalk.com/forum/sh...ad.php?t=206843

5: Chain slider: When grit gets in the space between your swingarm and the chain slider, it rubs into the swingarm and can eventually wear a hole in it. This is easily fixed using some silicone sealant as described by the late, great motoman393 here: http://motoman393.thumpertalk.com/tech/swingarm.html

6: Jetting: In stock form the bike is fairly lean. Once you free it up, it is REALLY lean. If your bike comes with spare jets, see if any are suitable for your weather and altitude. If not, either order appropriate jets or get the JD jet kit (available from thumpertalk). A little rich is better than a little lean.

7: Remove air box snorkel: US versions have an airbox snorkle behind the battery. Take it out.

8: Fuel screw: This is more optional than the other mods, but some people consider it to be necessary. Zip-ty makes the most popular fuel screw and it is described here: http://www.ziptyracing.com/display/...&CategoryID=110 Scotts performance, koubalink and MSR also make equivalent products.

Additional Notes:

Note 1: Oil choice and break in method are controversial subjects with many threads and no conclusions and will not be discussed here.

Note 2: Your electric start may not seem powerful enough. Once your engine breaks in and you have done some miles it will work much better. It may not ever work well on a cold engine in cold weather, but that is the price you pay for a relatively light e-starter.

[cruise]

What about cutting open the air box uder the right side cover.

[cruise]

just thaught i'd keep this thread going ?

[mousemeat]

Cheers,

Brian said that it would eventually make a good 'Tech Page'. I have been trying to get him to make it a sticky but he hasn't responded. I guess he is busy atm. I will try next week.

-W

[wantmorepower]

THANK YOU!!! I've been searching for exactly this. I don't own an 05 WR, however, onece I obtain one, I need to know how to do these mods without a fuss. The only thing you might want to add is some pointers on how to remove the AIS. I know what it is and what its for, but looking at the showroom models, I can't pin-point where it is. Thanks for the help.

[mousemeat]

I don't have an AIS to even look at, let alone disassemble. If someone else can provide pics and instructions i can edit them into the document.

[WheelsUp]

1: Throttle Stop: When your US spec bike arrives,

3: Grey wire: only applies to US spec bikes.

The Canadians got "Californicated" this year.

Dunno about Euro or Aussie bikes... though I've heard that Euros have had AIS for quite some time.

5: Chain slider: When grit gets in the space between your swingarm and the chain slider, it rubs into the swingarm and can eventually wear a hole in it.

Supposedly fixed for '05. I haven't taken my '05 250's slider off, but the screw attachment is different. There is now a large flat-headed screw holding the slider down and there is no "cup" as shown in the FAQ photos.

Still probably wouldn't be a bad idea to throw in a layer of sealant just to keep crap out from under it, but it no longer appears to be loose.

[mousemeat]

Will add these changes later. Cheers

[joshbeene]

I cut open the air box on the right side and I can tell it helps it breath. Especially when your filter gets a little dirty and needs the extra bit.

[wantmorepower]

I cut open the air box on the right side and I can tell it helps it breath. Especially when your filter gets a little dirty and needs the extra bit.

I'm curious, why did you open the airbox on the right side? Wouldn't it make more sense to open the airbox at the top? Am I wrong?

[WheelsUp]

That worked fine before they added e-start in 2003. The battery now occupies the space formerly blanked off on the WRs.

You can remove the snorkel (silencer) from the top/rear of the airbox and increase the opening size by about 50%, but you can REALLY open it up on the right side. There is still an outer cover in front of the number plate, so it doesn't look ugly.

[mousemeat]

bump to keep it alive. will incorporate changes when less busy.

[Texas4play]

bump.....................

[Texas4play]

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[NickZwr450]

Also the right side of the airbox has grooves where it looks like the manufacturer isjust begging you to cut it out. I used a utility knife and put a screen over the holes just to be extra sure, although I think this is really not necessary.

Now my bike idles all crazy and backfires a bunch too. Any advice? Do I need to rejet or just adjust the fuel screw? Any help would be appreciated. Thanks

[Texas4play]

Also the right side of the airbox has grooves where it looks like the manufacturer isjust begging you to cut it out. I used a utility knife and put a screen over the holes just to be extra sure, although I think this is really not necessary.

Now my bike idles all crazy and backfires a bunch too. Any advice? Do I need to rejet or just adjust the fuel screw? Any help would be appreciated. Thanks

What else have you done other than cut the side holes out?

[NickZwr450]

Just the Throttle stop. That's it

[Texas4play]

You'll need to rejet, replace fuel screw and remove the a.i.s.

Also remove the exhaust snorkle and replace it with the PMB insert (works very nice)

Disconnect gray wire

[NickZwr450]

Took out the exaust snorkel (baffle) and it is way worse. Make me think that it is just way too lean so I'm going to get the JD and probably the AIS removal kit. Do I really need the PMB insert or can I just run without? We run in the desert so no cops around that care how loud the thing is.

What does the Zip T fuel screw do exactly? Does it change the setup or does it just make it easier adjust the fuel screw on the fly?

Also I don't really want to do the grey wire mod but don't think that will make any difference to the problems I am seeing anyhow. Let me know if I'm assuming incorrectly. Thanks again for the advise, the help is very much appreciated.

[Texas4play]

It's definitely lean, no doubt. The JD kit will help eliminate that problem. I've seen a variety of tuning options so you need to research what might work best for your bike. My specs work great for my bike and other owners with exact same bike did not. It can be trial and error but you can research a good baseline on TT for your locale.

The a.i.s. needs removal or you will get backfire on decel.

The PMB keeps the noise down and the power up. You can view the dyno results on their website. With no snorkle the exhaust has no direct streamline out of the end cap. I ran mine without one and it just sounded like the exhaust was bouncing it's way out.

With the PMB its clean and crisp and thats what I like.

The zip-ty fuel screw is for on the fly adjustments but will make things alot easier getting it dialed in. Also, you'll need a pick tool with 180 degree hook to unblock the factory fuel screw.

The bike is tuned for half throttle from factory. The gray wire grounds the cdi map for half throttle settings. Disconnect the gray wire. You'll have the tank off anyway when you JD your carb so just do it then.