It's been a while since I've visited this board since I spend sooo much more time riding my Tuono instead of the Blackbird. (a shame i know)

I hopped on my '97 last week and immediately felt the brakes needed some work. I've got 'bout 66k on her and thought of doing pad work, fluids, etc. Fluid is easy enough and inexpensive so I tackled that this past weekend. Much to my surprise, I couldn't!

When I squeezed the handle, then open the bleeder valve. Nada! Went a full two turns on the valve and still nothing came out. AFter trying the other side, with the same results ... and scratching my head for a bit, my bro tells me to measure my rotors.

I dont have dial calipers (?) so I used my lil mm ruler (i know not very accurate) and measured something like 2-3 mm. His thought was that if the rotors are too thin, the brake calipers have travelled all the way out and cant compress to push the fluid out. Is he right? Do I need new rotors? What is the thickness of new rotors?

Any help would be greatley appreciated! thanks!

If you have pressure, and nothing holding them back, you'll blow the pistons out of the calipers...and I'm sure you'd notice that happening.

lol .. true, true ... but i have 2-3 mm left!

know where i might get a deal on some new ones? or slightly used ones?

what year?

On a side note (kinda), which bleed valve were you opening?

Center one goes to the rear pedal, squeeze the lever all day and you'll get nada. Upper valve bleeds the front lines and associated cylinders/pistons.

I have a '97.

U know .. i WAS doing the center valves. I remember seeing a copy or print out of the service manual years ago which indicated the middle valve was used to bleed the linked brakes.

from what i recall ... front RH center, front LH center, rear center, then rear outer valves. Am I wrong?

They are all used to bleed the linked brakes- some of them just don't go where you think.

I can't comment on the order, mine are de-linked so I've never done it. I can tell you that the center valve on all three calipers goes to the rear pedal, the upper valves on the front calipers goes to the lever on the bars, and the outer valve on the rear caliper goes to the secondary cylinder on the front forks.

There is a set on eBay right now - http://cgi.ebay.com/ebaymotors/ws/eBayISAP...&category=35601. Not sure what year though...

Description says 1997 :P

Those are the earlier carriers as well, if you're looking for proof beyond the ad text.

I know it sounds that I don't know what I'm talking about, but if you have not tried different brake pads (not necessarily different brands, just a different set) then do this before investing in rotors.

I had a shudder recently, and changing out brake pads and cleaned the rotors well with scotchbrite and brake cleaner. No shudder anymore.

Not sure if this is your problem, but it's worth a look.

That's the same problem I have right now. Only get the shudder when they're hot, and you're hard on the brakes.

Light braking & there's no shudder.


FWIW, I doubt your rotors are worn that badly @ 66K. Get a proper micrometer to measure the rotors, or even a set of calipers to measure them accurately.

If you feel you don't have enough braking power, switch to a more aggressive set of pads, and bleed the system. Big improvement, IMO. :D

thanks for all the replies guys ... i'm gonna go work on changing the fluid now ... but would like to clear up just one more issue. can anyone tell me what the thickness of a new rotor is? or tell me whether i'm beyond the service limit of my original rotors? i'm measuring between 2-3mm on all 3 rotors.

thx for the find! was able to save myself a coupla hundred bucks right there. now lets see how used those rotors actually are.

You sniped me out of them on E - Bay but you are welcome to them. Mine is a 99 and I would have to change the carriers to use them. I believe they begin life at 5 mm and are past service at 4 mm. Mine are about 4.5 with 24 M on the clock. The aggressive pads a lot of these guys run are pretty hard on them. I think you got a deal either way. Good luck

ah dude, sorry 'bout that. i verified the wheel type and decided I had to get 'em .... if 4mm is the service limit .. i guess i should be putting these on sooner than later.

I accept all kinds of payment in favor! :D

Now I'm going to have to go measure my rotors. I can't believe you wore yours out. I'm at 60K miles, braking is fine.

Also if you only measure with a ruler the pads don't even ride to the edge of the rotor so no wear there. You're measureing the new size.

EDIT: I just measured my left front rotor with a micrometer in the middle of the wear area, figure it has the most wear with the LBS. 4.5MM. New the manual lists them as 5MM. So I figure at 120K miles I may neeed rotors. 8)

F!!

it turns out my bro 'borrowed' my Dad's calipers last time we were down ... they look exactly like this:
[img]http://store1.yimg.com/I/cvfsupplyco-store_1845_17028617[/img]

i measured all 3 and they were exactly at 2mm!

hey... I don't mean to be critical or call you an idiot or something, but if those calipers look like that, they're probably standard right?? You mean that they are 0.2" I think... WHen those things say "2" that's actually about 5mm since there are 25.4mm in an inch, and only 10 tenths of an inch in an inch... 2/10 is 20% or an inch... 20% of 25.4mm is 5.08mm.

Mike

Edit, those are for sure "standard" (not metric) if they go up to 10, 6 times... Most calipers like that are 6" calipers

2mm :!: :shock: At 66k miles!

What pads are you using so I NEVER use them?

Pete... see my post right before yours...

Mike

In the majority of Jap bikes, the service limit is stamped on the disc (rotors).

In the Bird, for the front ones it is in the hub (remember semi floating discs)
and it reads TH. 4 mm, while for the rear is closer to the friction area and it reads MIN. TH. 4mm as well, where MIN. TH. stands for minimum thickness
(please do not comment on the explanation, somehow I felt I had to do it).

Now if your rotors are 2mm thick, this can be observed without even looking, just by touching them.
Replace them asap because:
a) your brakes will overheat too easy in case of fast riding
B) your rotors might develop a crack between the cooling (or pad cleaning) holes. This eventually will brake the rotors from their centre and can result in a serious accident.

When I used to ride my XR600 on a daily basis on the street (with high gearing good for 95 to 100 mph top speed), both rotors developed cracks
without even the slightest wear on them.
This was 'cause they were designed for dirt use and they are thinner.
If I remeber well when new the front is 3.5 mm and the service limit is 2,5 mm.