05 WR450F Surge

Hi all,

I have a 05 WR450F it has 25 miles on it. I realize it is not fully broken in but I have an annoying surge trying to hold a steady speed. It seems to be more prevelent in first and second gear at lower rpm. It feels like a lean condition like it is running out of fuel. Has anyone with an 05 experienced this? Is it normal? Will it improve as the bike breaks in? It is not so bad that I cant live with it at this point but If it gets worse I will have to do something about it. Any info would be greatly appriciated. Thank you in advance. Forgive me if this has been covered in another post I seem to remember hearing somthing about these bikes having a surge.

I forgot to mention the bike is bone stock no free mods with stock throttle stop.

I forgot to mention the bike is bone stock no free mods with stock throttle stop.

Oh boy...............

I don't even know where to begin....

Replace the throttle stop with a YZ throttle stop... Or you can cut your stock one..

Under the tank you'll find a cluster of wires that go into a connector, there lives a grey wire, remove it from the connector, fold it back and tape it down using electrical tape.

You need to jet the bike, Go to the jetting Database here and look at what the rest of us are running, it will save you a lot of time...

Remove that silly little snorkel on the top of your airbox, it's useless....

Remove that silly little snorkel that's inside your muffler. Again, useless...

That should get you going for now..

The most important thing you can do is to do a search here for these mods, they're everywhere.. They get repeated everytime a new guy gets a bike.. Have fun..

Dan :naughty:

Welcome juiceman

the salesman should have told you about the mods. With out the mods

the bikes performance is lacking big time. BEFORE YOU DO ANYTHING ELSE DO THE MODS... Like Dan said do a search. There are

a lot of veteran riders and info here at the TT site to take you and your ride to the next level. Enjoy :naughty:

I found with my 05, it takes a little while to really warm up and when its not it does surge. The more miles I got on it the better it ran, I thought it was a POS for the first 100 miles.

My advice: put 100 easy, soft, gentle miles on it ( to break in), then see how its running, then re-jet for your altitude and normal temp.

25 miles...change your oil and filter ASAP!! :naughty:

Do 100 easy miles, 100 semi hard miles, and then beat the crap out of it!

Ooh, and change the oil and filter as much as you can for the first couple hundred miles, it will break right in, no more surges!!

I think you guys missed Juiceman's earlier post where he said he was a beginner rider and planned to keep his new WR450 bone stock for a few months til he got used to it before doing the free mods. Pretty smart idea IMO.

Chevy, considering he's already complaining about a "surge" in power I don't think there's anything wrong with helping him out. Nobody said anything about cams, aftermarket exhaust or any other hop up mods, just a little uncorking to get the bike to react the way he needs it to. Even a beginner can benefit from uncorking certain elements on the bike. :naughty::naughty:

The surging can be caused by a lot of things with improper jetting topping the list and the fact that the bike is not yet broken in. If you are at sea level or near it, your bike is running so lean that you could damage engine parts if you don't fix the jetting. As far as the method for breaking it in, take a look at this website... http://www.mototuneusa.com/break_in_secrets.htm. It's a rather controversial topic, but I followed this method with my '05, and it's a screamer now. Changing the oil frequently in the first few hundred miles is also a must. Get yourself a Zip-Ty magnetic drain plug and you'll understand why.

Once you get the thing broken in and jetted right, if you still have a surge, you may want to disconnect the TPS. Once I unhooked mine, which is simply a matter of unplugging one connector, my surge went adios.

If you don't do anything else while you get used to the bike, at least install a YZ throttle stop and get it jetted properly. This will allow you to get the bike to rev properly, facilitating break-in and seating your rings in a more efficient manner. After that, it's up to you. Good luck and welcome to the club...SC

My bike started the first time and then I could not get it started after that. I am not real mechanical so I took it to the dealer and spent 80 bucks and they took care of the mods and found out the dealer did not prep it very well.

Thanks for all the great info! I went to my local dealer today and the tech there sudjested I remove the throttle stop and run it for a few miles to see how this bike should run. Wow! This is great I love the power this bike has I was getting concerned as it started feeling slow to me. But now I cant get the smile off my face! True I was planning on waiting for the mods but I cant go back now. The tech told me to just cut off the the throttle stop above the threads. somewhere else I read it had to be a certain length. I asked the tech and he said all I needed it for was to plug the hole so dirt wont get in. Is this true? Or will I damage something if there is not some kind of stop there? Oh and I changed my oil and filter this evening with 35 miles on the bike. I have to admit the last 3 miles or so I was hammering it hard with the throttle stop out. 3rd. Gear up in the rpms twist the throttle open and the rear tire breaks loose this bike is going to be fun! I will look in to jetting as the bike acts like its lean.

My 05 WR450 was doing this AFTER the Free Mods -- only after installing the JD Kit per the instructions (Red needle, middle clip, 170).

JD said to substitute the Red needle in place of the Blue -- this fixed it. So, (not being a wrencher) I assume that means it was "rich" and the Red needle "leaned it" out.

If you intend to do the Free Mods, do them first before messing with the Jetting. Also, don't forget to do the Lowedog kit to smooth-out the bike's throttle response.


Regarding the throttle stop, you can't just run without one or with one "just plugging the hole." :naughty: You run the very real risk of having your throttle stick open and killing yourself and the nice new bike you bought. You can cut the old stop to 18.23mm or just buy the YZ stop, your choice, but pick one. Your tech sounds like he's a friend of the crack pipe...SC

Thanks Steve it did not sound right at the time I had ordered a YZ stop on Mon. I have reinstalled the WR stop :naughty: until I get the YZ in.

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