Front brake squeek and grind

I have a 2000 WR and have only rode it about three times and when I use the front brake it squeeks and grinds bad. I looked at the front pads thinking that maybe they installed one on backwards if that can be done, all looks ok. I haven't taken the front wheel off yet to check it out that way still a little lazy on doing that yet. Thought mybe it is something any of you out there have heard of or experinced.

Brake noise is usually the result of vibration induced by loose parts or out of true / warp conditions. If the pads are OK, then your rotor may be warped. My WR400 had a warped rotor and out of true front wheel from the dealer. The front brake sure squealed and the front end shimmied at speed. Fix: Step 1 true your wheel. Step 2: Buy a new rotor or true you rotor.

Truing a wheel: Put a screwdriver or socket extension (or dial indicator if you are really loaded with tools) resting against the fork/swingarm with the tip next to the rim, then rotate the wheel. A dial indicator is preferred. (You can pick up a decent dial indicator with a magnetic base from mail order tool supply houses for about $35.) If the wheel is true, the tip of the tool/indicator will show nearly constant lateral and vertical position of the rim during the full rotation. If not, then you will see the variation. The wheel runout spec is .080" or 2mm lateral and vertical. If it is way out of true, it is best to loosen all spokes and start gradually tightening all of them while checking how true it is. If the wheel has a deviation to the left, slightly loosen the spoke that attaches to the left side of the hub and slightly tighten the spokes that attached on the right side of the hub. This will pull the rim to the right. A note the truer the wheel the less vibration and less rotor warp. Get it as true as you can. I trued mine within about .020” or 0.5mm.

Step2: Rotor Truing (CAUTION: ROTOR TRUING IS NOT YAMAHA AUTHORIZED) The brake still squealed a bit, so I went after the rotor. You will need a dial indicator to check/true a rotor. The runout spec on the front rotor is 0.006”. Mine measured 0.009”. Yamaha recommends replacing the rotor if out of spec (assuming the wheel is true). I placed a small piece of hardwood (3”x1”x1/4”) on either side of the rotor and placed a crescent / adjustable wrench over the pieces of wood and tweaked / bent the rotor to correct the warp condition. Start by bending very slightly and measuring runout each time. I got the runout to 0.005”. This saved me from having to buy a new rotor.

Result: much better brake performance and no dealer / parts hassle.

Eric in WA


’99 WR400, YZ timing, IMS Tank, YZ Seat, Acerbis Handguards, Scotts Steering Damper, Renthal Bars, Yamaha Full Skidplate, Devol Rad Guards, Dunlop 755F & 756R Tires

’99 Polaris 400 Scrambler –“Trail Couch, Toolbox and Lunchwagon”

’99 Honda Z50R, ’97 Honda XR70R, Kubota L275DT and an assortment of farm equipment.

I have the same problem on my 2000 WR it sounds exactly like when your brake pads wear down and are metal to metal (happended on my 91 KDX 200) I thought that maybe yamaha put abrasive metal in place of my brake pads, that is how bad it sounds! Also when I quickly tap my back break it has a clunk sound as if something is loose but I checked it and everything seemed to be tight.???? puzzling??? Any suggestions anyone? Thanks , great site I love it!

My 1997 ATK 605 had a warped rotor right off the showroom floor. ATK replaced if free and the new rotor worked just fine thankyou.


I trued my wheel per Eric's intructions about a month ago. It was surprising easy. It was very easy to tell where you needed to tighten spokes to true the wheel. I loosened all my spokes first then did it. Took only 10 minutes. I also used the "ping" method to make sure all the spokes were tight enough. Just hit your spoke wrench against the spoke. If you get a dead sound, it probably is not tight enough.

I use to never check my spokes. Now I do it every other ride at least.


Dougie, '99 WR400

Mods: YZ timing, Race Tech Suspension, FMF PC IV, FMF Hi FLo Moto, YZ seat, IMS 3.3 tank, One Industries Graphics, Renthal bars, 14/52 gearing.

How tight should each spoke be? Do you tighten each spoke gradually?

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