2009 CRF450R Front Brake Issue - Dragging

Hey guys,

I was wondering if anyone else has some insight....

First off, I'm not a nOOb in the garage, as I am an ASE Auto Tech...Secondly everything on the bike has been thoroughly cleaned, inspected, and lubricated.

Now for my problem..... few weeks ago I took the bike out for the first ride since I built it, at RedBud had a blast, loved the bike (coming from an 06 YZ450F) I got my front end cleaned out at the LH turn after the ski jump, from someone who was whiskey throttled or regardless outta control. I picked up and remounted, same lap after the rollers/whoops I noticed the front end knifing hard, so I pulled off in the bottom before Laracco's Leap, and noticed my front brake dragging significantly. So I rode back to the pits lofting the front end, and pulled the pads apart with a screw driver. I pulled the caliper and inspected. I didn't see build up as if the dust seal was torn, knicked, or leaking allowing sand/dirt into the piston bore. Verified caliper moved freely on the guide pins - check. Next best I could I checked the rotor for a bend - passed check. Threw it back together, and bled the front brake off... Circled the pits, and it worked well. Next session out, halfway through it same thing....

Now the OEM rotor and front pads were still on the bike, because my CRFSTUFF front rotor hadn't arrived yet. So I wanted to wait for the new pads to go on with the rotor.

Current date... I installed my front CRF STUFF 280mm rotor, and bracket, CRFSTUFF braided line along with new pads, CRFSTUFF front line, and Blue anodized pad pin. Used some red scotchbrite on the guide pin, and a bore brush inside the guide pin bores, and re-packed with Sil-Glyde, applie Sil-Glyde to the back of the pads, tension clips, as well as the Caliper Pan Guide Pin/Bolt. Pulled new 5.1 fluid through with my vacuum setup. Verified level feel then. Yet I still have a noticeable drag as in; if I pump the lever 10 times I couldn't free spin 1 revolution.

So I begin thinking well surely the fork lug isn't bent or tweaked. I removed the front wheel, and used a straightedge and verified it to be on the same plane as the other caliper mount. Inspection I see no stress marks on the fork lug as my lucks are painted with Eastwood Y2K Extreme Chassis Black - Gloss, and surely would see impact or stress cracks and there are none....

So I turn to you TT Gods..... (Shawn) lol

Also the fluid level is fine in the Master Cylinder.

Id have you pull the caliper and pull the piston and make sure you didnt end up somehow getting some fluid past the seal some how. As an ASE cert mechanic, you understand the little square seal is what is supposed to retract the piston ever so slightly when the lever is released. Id also have you verify the masters piston is retractiing correctly and not blocking the supply port in the master cylinders resivior (which would prevent the tiny seal in the caliper from being able to back off the piston).

It wouldnt be the first time for the line to be bad and act like a damn check valve too.

OK, so with that level of detail working on a bike, I'll be over tomorrow to drop my bike off. Just go thru everything.

If you took a hit on the left side and it was on the front wheel, I'd check to make sure the caliper mounts (cast into the fork lugs) didn't get tweaked. I chases a dragging front brakes for months until I found the lower mount was bent ever so slightly. Replaced the lug and it was good as new.

Wheel spacer? I would see if someone would let you mount up their brake assembly real quick, that would tell you if problem is in brake system or mount system.

Had the same problem with me 2013, although it wasn't quite as bad. I did the same to correct... did not work, still dragging. Can't explain why but after a couple weekends of riding the problem corrected itself. I must say though, the first ride after doing the work to correct, my fluid level dropped by half...must have been trapped air in the master cyl that was causing my problem.

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