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I Got A Bent Brake Disk, What To Do?


Burkov

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Hey guys, i had a lay down with the bike a few months ago. I fixed everything, or at least thats what i thought.

There was a vibration while braking, so after a check it appears that the left brake disk is bent.

Both disks have 4,5 mm thickness, so do you think i can get only one new disk, or can i get a second hand?

They are damn too expensive new, so i was hoping to get a second hand.

Of course it will be checked for thickness and bends, but what do you think?


Here is the bike with the new paint (i decided to change the silver with the darker one)


post-28705-0-35392700-1411648968.jpg

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Assuming the run-out and thickness are within specification and the rotor does not have any grooves, used is fine. After all, the other rotor on your motorcycle is "used" and works fine.

How did you determine the rotor is bent? Did you measure run-out?

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You could always straighten the bent disc, they are just lumps of metal & I've bent a few straight over the years.

If you rig up a measure on the fork leg, you can often do it on the bike. Just identify the middle of the bent part & then move it to the bottom at the 6 o'clock position, then use a large adjustable spanner, tighten on disc in the middle of the bent part & pull it out, usually takes a few goes with some trial & error, less is more, you don't want to bend it to far !

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The bike is at a friends mechanics shop.

He told me that it is even visible where the bend is. He also said it is on the carrier, not the rotor.

I've seen a few videos of disks being bent back, but i'm not sure, how long will it last that way.

He said that he will bend it back as far as possible, but the bend is too much and is good to have it replaced.


If you know someone from europe, who is selling a spare disk i would be glad to take it :P

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I bought a set of used rotors off of eBay for around $75 (USD) each. They within spec and bolted up no problem. The key is to read the "fine print"! Some people will sell damaged or out of spec goods as there are those who can fix them and will be willing to buy them cheaper and just fix/repair them instead of paying more for a part that is within spec or undamaged. Good luck.

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EBAY

look for VFR800/VFR800 Vtec

also CBR600F4/CBR600F4i

same front disks. there may be a few others as well

F4i rotors do NOT work, but yes to F4(99/00) and some year Gold Wing rotors.

If you have a dial gauge set-up straightening isn't that hard, I've done dozens of them on the bike.

I use a hammer and wood to motovate a change, others use an adjustable wrench and bend them back.

BR

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Good.

FYI and the forum users can always reference this pinned thread...it lays out a couple approaches in detail...not too long, read the whole thread...easy peasy !!!

http://www.vfrdiscussion.com/forum/index.php/topic/8-brakes-warped-rotor-fix/?hl=%2Bbrake+%2Brunout

BTW my carriers were bent over a tenth of an inch....one YEAR later and they are strait as ever, no issues with "spirited" riding.

Matt

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I just got the bike from the shop. The guy did a great job and there is no bend in the carrier now. I have a new blue brake fluid too :P

you better ask what fluid they used!!!

DOT 5.1, DOT 3 and DOT 4,are polyethylene glycol-based .

DOT 5 is silicone-based...

​they are not compatible..

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