05 WR450 - Searched, but still a few questions...

Hello everyone, first post here in this great forum!

I just got a new 05 WR450 on Friday and I have a few questions. I have searched and read for about 3 straight days now and still have some unanswered questions….so here we go.

1. The air box mod… I am planning on doing just the snorkel because I ride mostly on muddy, wet trails up in the hills. Will this be sufficient, or will I even notice a power increase? I don’t really want to have to cut the top off, but if I must, I must.

2. The new exhaust… Seeing as how the 05 have new pipes, I have heard conflicting info on modding them. Some people say you have to drill out the baffle, and some make is sound like you can just unscrew all the allens then remove the whole damn thing. Won’t I lose my spark arrester if I do this? And if I do have to drill it out, am I going to be too loud in the hills? Would putting an 04 pipe (buddy has and extra 04 stock pipe) be the best solution?

3. Idle…. Will doing the grey wire, snorkel, and something with the exhaust solve the stock idle problem? (Mine wants to die unless really, really warmed up or choked).

4. AIS... I am confused on this...is there an easy way to disable/bipass this? Do I need to do it?

5. Do I really need to do the jetting after the mods, if not; do I need to do anything right away to make the bike run better after the mods?

Sorry for all the newbie questions, but I just spent some $$$ on this beautiful beast and I want to make it run like it is supposed to without causing any kind of damage to it in the long run.

Thanks for reading, and I look forward to any tips! :)

#1) To pull snorkel out: Drill out rivets holding battery strap clip, snorkel slides right out, replace clip using small ss screws so you can still hold down battery. You could actually put it back in if you want. (No broken pieces).

#2) The new exhaust: you can remove the straw with allen wrench and spark arrestor stays in with same bolts.

I have found not to have to re-jet unless you put an all new exhaust on (FMF, white bros, ect..) I ride at 5000' however, and it is running slightly rich the way I like it.

I have done all the free mods in a way which I can put it back the way it came, no problemo :)

I also am a new (05) WR450 owner and here's my experiences from forum info and doing the mods.

1. There is no top to remove, so follow directions for removing snorkel and you're done.

2. The pop rivets on the side of the little "Stinger" are all you need to drill out. Once these are gone, you can pull out the inner sleeve with needle nose or channel lock pliers. You can also re-install it with a pop rivet gun if you need to.

3. There is a black Throttle Stop rotary knob on your carb, just below the choke pull. Rotate it to set the idle once you've warmed up the bike.

4. AIS doesn't seem to make much difference on my bike, however I did just buy the removal kit from Thumpertalk Store and will attack it today.

5. I also put the JD jetting kit in when I did all the other mods. I'm not sure if it was necessary, but typically, bikes are delivered slightly to moderately lean for emission reasons. You did not mention the YZ throttle stop in your post, so I'd be sure you make this change above all others for a performance gain.


2005 WR450FT

1995 Harley Springer Softtail

Cool, thanks guys!

And yeah, I did do the throttle stop already. I also took off the back swing arm and lubed everything up (didn't really need to but my buddy was doing his so I figured why not repack it)

There was a great article on the bike recently in Dirt Rider. They listed some of the mods and raved over the new tank/slimmer feel, power, exhaust system, and suspension/handling. I would definitely read it! They even went so far as to say they were turning faster lap times on an MX track on the WR than an 05 RM250!


#2 If you can get an 04/03 exhaust cheap, it would be better than stock as you have many different insert choices to improve power without noise. The stock 05 muffler is restrictive internally. There are many aftermarket mufflet choices, also.

#4 You can easily use rubber vacuum hose caps to block off the tubes that go to the AIS. Then, you can test it yourself. It really does not help performance, but it stops popping in your muffler. It also gets that thing out of the way of the carburetor.

#1 It is not as noticeable as driving with the side airbox cover off. Look at the snorkel cross section (head on). You can see that it is less restrictive to remove it, but is it significantly so is a matter of opinion.

All the free mods are subtle (like the snorkel). Some seemed not worth the time. But, the overall effect of all of them togeather makes a noticeable difference.

I did not have to drill out the rivits holding the battery hold down strap. All I did was move the battery out of the way and the box flexed enough that I could pull the snorkle out.

Easiest way to remove the snorkel... Take off seat. Open airbox access panel. Take a large slotted screwdriver and place it near the center of the snorkel. Hit it with a hammer and the snorkel will split in two without damaging anything else. Continue hammering the pieces lightly until they fall into the airbox where you can pull them out with your hand. No fuss, no muss. You'd have to be a complete retard to screw it up.

As far as the exhaust goes, I don't know what these guys are talking about regarding drilling rivets and other things. Take a 3mm and 4mm hex key, remove the end cap, then remove the little silly straw-looking thing underneath the cap. It's held on by 4 allen head screws. Put the end cap back on and you're done. The spark arrestor can be clearly seen when you remove the straw and it remains intact, so no worries.

With jetting, you may have to rejet, but maybe not. Every bike is a little bit different. These bikes run very lean in stock configuration in order to get green stickered, so the majority of people are rejetting. Get a hold of Indy's jetting chart and that'll will get you very close to where you need to be. I think it's wise to invest in the JD jetting kit regardless, as the adjustable needles are priceless. The extra main jets don't hurt either. It took me about 3 days to get my bike dialed in, but now it runs like a striped-ass ape.

Your idle problem could be a combination of things. My advice is to screw the idle control all the way in, then gradually screw it out, testing the results as you go. Jetting and air starvation prior to the airbox and exhaust work can also be a factor. It's an art rather than a science.

Get rid of the AIS. You're most likely going to be in and out of the carb for a while and it'll make a world of difference as far as access to it goes. It's already cramped in there, so if you can make it better, do it. Once it's removed, there is virtually no performance gain, other than it makes it easier to diagnose your carb settings as there is no secondary influence with regard to sounds coming out of the exhaust. The AIS makes the bike pop and fart which are also signs of improper fuel mixture. No AIS equals no second guessing. It's an easy mod, just don't forget to get some RTV sealant before you proceed.

Lastly, the Grey Wire and Throttle Stop mods go hand in hand. The Grey Wire retards the timing to compensate for only having 1/4 throttle ability. With a YZ throttle stop allowing full throttle usage, the Grey Wire needs to be pulled to utilize the rev range properly. My advice is to pull it out of the harness and tape it off rather than cutting it.

I just got my bike a little over three weeks ago and I was also very leery of tearing into it for fear of killing it. I'm over it now. The bike is so different than the day I brought it home. The only mod that is moderately irreversible is the AIS as it requires you to drive aluminum plugs into the holes the AIS formerly occupied. Other than that, it's all reversible. Just do it, you won't be sorry...SC

I got a 05' WR450 a few months ago and have just finished doing all of the mods. Like jdd123 said, any of them by themselves don't seem to have too much of an impact but all of them together really help open the bike up. I'll comment on my experience:

1) I only removed the snorkel. I didn't have to drill or cut anything. I just moved the battery and harness out of the way and used two large flat head screwdrivers to pry the snorkel away from (battery) side and then pulled it out with vice-grips.

2) I just put in the ProMoto Billet insert. This was the last mod I did and it seemed to make it rev smoother and maybe bumped up the power a little. For $60 it was much cheaper than than a new exhaust and the bike has plenty of power for me. I can't really comment on an 04' exhaust but if you can get one for cheap why not give it a try? I assume it will fit since no one said otherwise.

3) My bike idled terribly at first. As I did more mods the idle seemed to calm down. I am not sure what the main causes of the eratic idle were but now I don't care since it seems to have gone away for the most part.

4) I'd just get rid of it. Order the Lowedog kit to make it easy. After doing it to my bike I got rid of any backfiring and it seemed to rev slightly better. Plus it is a lot cleaner and easier to access the carb and rear suspension.

5) I would say do the jetting. From my understanding you should rejet everytime there is a significant seasonal temperature change or your riding elevation changes significantly. In any case having the correct jetting will help the bike start, idle and run better. I was told all the 05' WRs come jetted way too lean to help pass California emissions. I could barely get mine to run before I rejetted. After I rejetted it ran great.

One other thing. Maybe I'm preaching to the choir here but make sure to take the time and get your suspension dialed. Set the sag and then take a small flat head screwdriver with you on a ride and mess with the compression and rebound dampening. That is probably the one thing I did to my bike that made the biggest difference of just about anything else I did. And it was absolutely free.


Wow, thanks guys! I have no idea what I would be doing if I hadn't had found this site! :)


2. The new exhaust… Seeing as how the 05 have new pipes, I have heard conflicting info on modding them. Some people say you have to drill out the baffle, and some make is sound like you can just unscrew all the allens then remove the whole damn thing. Won’t I lose my spark arrester if I do this? And if I do have to drill it out, am I going to be too loud in the hills? Would putting an 04 pipe (buddy has and extra 04 stock pipe) be the best solution?

I have an 03, so I can't help you with your 05. But if you go with an aftermarket exhaust, or your friends 04 exhaust, PM me. I would be interested in buying the 05 exhaust. (unmodded of course)

Good luck with the mods :thumbsup

Wow, thanks guys! I have no idea what I would be doing if I hadn't had found this site! :)


I know what i would be doing. I would be riding around a plugged up bike going 'Is that it?'.

TT is a good thing.

Stay away from Ford Trucks :):D:):p

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