New bike question.

Hi guys,

I just bought a new old stock 2004 WR450. I am returning to the sport after a three year hiatus to finish my bachelor's degree.

I rode my bike for the first time yesterday. It felt like the bike loads up and surges at low speeds. I was slipping the clutch just to mitigate the surging. Is this normal? It almost felt like it would stumble then hit when opening the throttle ever so slightly. I would like to try to smooth out the power to make it pretty linear. What do you guys suggest?

Other info,

6'2" 260 pound rider.

Bonestock bike, baffle and all.

99% of all riding is below 3500 ft. Yesterday was at about 1500 ft.

Novice to intermediate rider.

I want to putt along with my boys on their 50s and still be able to open it up with friends.

I am open to mods but like the bike quiet.

If it is truly bone stock it could probably use some fine tuning via the jets. To get them into the US Yamaha jets them extremely lean. Take a look and see what jets you are running now

First, congrats on the getting the bike!

I recently bought the same bike. It had very low miles, and had alot of gum in the carburetor from sitting. Also, the accelerator pump wasnt working at all... had to shorten the rivet in the diaphragm and increase the spring pressure on the linkage of the AP (accelerator pump). These are mods are all here...

http://www.thumpertalk.com/forum/forumdisplay.php?f=104

And for the surging, for on-road use i disconnect the TPS which eliminated my problem. Correct jetting is a must, but surging never went away intil i disconnected it for the street. Offroad, i still plug it back in.

Everything i've done to the bike so far has been previously documented here in the forums. The search engine is great! thanks TT!

Everything i've done to the bike so far has been previously documented here in the forums. The search engine is great! thanks TT!

Every time I really get into searching, I get a message that says the search function is temporarily disabled. :ride::ride:

I wish that I had more of a background with thumpers but I don't. I am a little apprehensive of changing jets but I guess that is where I should start. I hate looking at where that plug is to take it out to read it. It seems like jetting it will take all day to try a couple jets.

About the TPS, you disconnected it for road use but reconnected it for offroad. Doesn't it take more throttle control offroad? I also read in the manual that disconnecting the TPS will actually lower performance. Is this true? I really would like to make this thing more linear.

Is there a jet kit that you all would recommend? I've read about the JD kits when investigating a CRF450X but haven't read about jet kits for the WR yet.

Sometimes the search engine is problematic, but be patient because there really is alot of answers about our '04 WR450s.

I dont think you need a jet kit. The only thing i would recommend buying right away is an adjustable fuel screw.

I would start by removing the carb to clean it, and clean the fuel petcock too. You will need to drain all the gas to do this. Then, check all the original jet sizes in your carb. Write them down, this is your starting point. I went with a 168 main, left the stock needle in at clip #4, and went to a much smaller leak jet. When the carb is off, you can fill the float bowl with gas and pretend to slam the throttle to wide open. You can watch the gas shoot out of the accelerator pump. If it doesnt look like a mini squirt gun, then you've got some work to do.

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