Brake Rotors... Can they be cut?

[Hairyblackdude]

Team,

I noticed some brake pulsing on the front brakes this past weekend.

Upon further inspection, the brake rotors show uneven wear/braking surface.

It looks like they may be warped...

I can't find a place to purchase new rotors without spending $400+ for 2 of them..

Can our stock rotors be cut? How much does this typically cost?

-or-​

Do we have a source for cheap replacements?​

Thanks for any insight.
_marc

 

[TeeCat]

Marc, I think they're pretty thin, you know? So, I suppose it would depend on how deep the lathe would have to go to eliminate the warping. I'm just guessing, though.

TC

 

[Hairyblackdude]

Alright..

Just got off the phone with my cycle repair buddy.. He says you typically cannot cut them. They are too hard & usually just chatter..

He mentioned using a flywheel grinder to true them up a little bit, but he was talking like 20 yrs ago...

So, I guess Im on the market for replacement rotors that are in good condition.

Thanks !
_marc

 

[retiredgentleman]

Click on "Tech".................click on "Homemade Tools"................go to page 4, top of page.

These rotors get rough looking with grooves etc. Some emery paper will clean up the surface, if you spin them. They may end up being too smooth, so I use 40 grit sandpaper to rough up the surface.

I doubt that your rotors are warped. You would have to use a dial indicator with the rotor mounted in a lathe or similar.

 

[retiredgentleman]

These rotors are not hard. They were very easy to drill.

I'm sure a lathe could clean up the surface very easily.

 

[I am Carbon]

I agree with RG

 

[gggGary]

Not worth messing with, good rotors are a dime a dozen. I have a stack of the late model rotors.
+1 you need to measure. A dial indicator on a fork leg works fine. but it doesn't have to be that fancy. IF it has some run out unmount the disk and check the mounting surface for possible junk that got in the way of the disk seating correctly. Mark he disk and hub rotate the disk against the hub rebolt and check it again, What year is your bike where in the world are you?
Read this thread for some more info.
http://www.xs650.com/forum/showthread.php?t=1819

IIRC Jap rotors are made of some kind of hard to machine stainless and they are usually ground instead of turned. There is an eBay vender who grinds and drills or slots rotors fairly reasonably.

 

[oldbiker]

no is the real answer,,, but you can wash grind them without any dramas at all and doing them that way iis common regards oldbiker

 

[bobadame]

Might be easier to grind the mounting surface using the disc face to locate from. You would be removing less material from a stiffer surface. Less chatter. Then grind the working surface that's facing up. Then flip it and grind the front. Probably not worth the trouble but of course anything is possible.

 

[DirtyErnie]

+2 for RG. I took mine to the local O'Reilley's and they turned just fine. he had to run each side twice to get them cleaned up, and the long strings of stainless kinda scared him a bit. They're definitely NOT as hard as a cast-iron automotive rotor.

If they ask how thin, I hear tell some of the racer types are going as far as 5mm. anywhere around 6mm should be easy to turn to and work just fine.

Or just get another one from gggGary.
:-D

 

[InfamousXS]

I don't want to hijack the thread but RG mentioned using the emery cloth to clean up the surfaces and I wanted to know how you "spin them" like he mentioned?

 

[retiredgentleman]

InfamousXS

http://www.xs650.com/forum/showthread.php?t=37&page=4

The link goes to the "Tech" section. If you have a drill press, just make up an adapter.

 

[pamcopete]

MikesXS has new rotors for '77 to '84 for $143



http://www.mikesxs.net/search.html?q=brake+rotors

 

[Hairyblackdude]

Not worth messing with, good rotors are a dime a dozen. I have a stack of the late model rotors.
+1 you need to measure. A dial indicator on a fork leg works fine. but it doesn't have to be that fancy. IF it has some run out unmount the disk and check the mounting surface for possible junk that got in the way of the disk seating correctly. Mark he disk and hub rotate the disk against the hub rebolt and check it again, What year is your bike where in the world are you?
Read this thread for some more info.
http://www.xs650.com/forum/showthread.php?t=1819

IIRC Jap rotors are made of some kind of hard to machine stainless and they are usually ground instead of turned. There is an eBay vender who grinds and drills or slots rotors fairly reasonably.

gggGary,

I have an 80 & I live in PA near Philadelphia.. I converted a dual disc front end..

My buddy says he has a flywheel grinder at his old job & he is gonna check to see if they will do it.

I will gladly pay for some rotors that are flat tho.. The flywheel machine kinda seems like a hassle & I dont want to pull any strings if I dont have to.

Thanks !
_marc

 

[Hairyblackdude]

MikesXS has new rotors for '77 to '84 for $143



http://www.mikesxs.net/search.html?q=brake+rotors

Thanks for the link... However, they are showing as "out of stock".

Mikes will not let you complete an order with items that are not in stock. There are several things I need from there that always show "out of stock". Id be willing to wait for them, but I have to just check periodically-- just stupid.

Thanks.
_marc