No brakes

[talonboy]

So I have had the Tenere about a month, was out on my first real off road ride today. 22 miles down a gravel/rocky trail and back. About half way back I suddenly notice the front brake lever comes back to the grip! Well, 3 or 4 pumps and it comes back, seems normal. Rear brake is fine. I try the front brake again, and it comes to the grip again. I stop and do a quick look over, nothing visibly wrong. Well limp home, and do a little testing. Left front rotor is bent. Pull wheel off, then notice a rock must have been kicked up against the brake carrier, bending it. See attached picts. So, now I research a solution.

Years ago I had a similar thing happen, strangely enough to another Yamaha, a WR400. Since it was early in the days trail ride, and I would prefer to have a front brake, I beat the brake rotor mostly straight with a couple rocks. Worked well enough to finish the ride. Later I was able to straighten the rotor and not have to replace the rotor.

 

[EricV]

That sucks. Looks like it took a pretty good hit.

Give Motorcycle Tire Center a call. They did a great job of straitening a bent wheel on my Super Ten early this year. Great guys and fantastic prices. They totally saved my Death Valley weekend by doing the wheel repair while I waited in about an hour. They may be able to straiten the rotor, or at least tell you if it's possible or you should bit the bullet and replace it.

MOTORCYCLE TIRE CENTER
2116 E CHARLESTON BLVD
LAS VEGAS, NV 89104
Phone: (702) 382-8824
Fax: (702) 382-6816
Email: mtclv@cox.net

 

[Don in Lodi]

Wow. You'd think you woulda felt that wack. Amazing how fast a little wobble will push the pistons back. If you can free up the floating portion of the rotor it might be all good. The parts fiche show it as a complete assembly. I've never had floating rotors before, can they be taken apart?

 

[talonboy]

All is well, brakes seem perfectly normal after a short ride this morning. Will need to keep an eye on it.
I took the wheel and rotor off, last night. Beat the carrier back as straight as I could, but it still seemed a little off. I researched floating disks on the Internet, and found people doing this to stock rotors, mostly for road racing. There seemed to be two methods, dent the back washer a bit, to give the rotor a bit of float. Second method was cut out the thin spring washer, to give the rotor more float.

I tried the first method on the one damaged button, but it didn't seem to give much free-play. Maybe if I had done all of them, that might have worked.

So I tried the second method, plenty of free play on the button, but little if any on the rotor. So I did the next button in each direction from the damaged one (three total). That seemed to give the rotor a bit of movement where the carrier was bent. In summary I removed three spring washers and gave three buttons free play. Reassembled everything, rotor seemed to spin true via my screwdriver held against the caliper mount measuring tool.

Thanks for the ideas. I have met and ridden with a couple guys from the Motorcycle tire center previously. Great guys.

Yes I felt many a whack from rocks I hit, but nothing that that stood out. Yes, a bent rotor will push the pistons back in the caliper, so when you grab the lever there is nothing. But what seemed different here, was after a few pumps, the brakes felt normal, no pulsing while braking from speed. I rode about 40 miles of pavement home, and had to stop numerous times. The time I bent the rotor on my WR400, the brakes could be pumped up, but the brake had a terrible pulse while braking.