stopping power?

[tab1324]

So I'm curious...

What do people generally think of the stopping power of their XSs and XJs. I've got the XJ and installed stainless line up front. I'm still not all that impressed with the brakes. I've rebuilt the master, cleaned the front calipers, bled and bled the lines.

It stops but it just doesn't feel like it has a lot of extra stopping power. Like I rode my brothers roadstar and when I stopped for the first time I chirped the front tire cause the bike has such good stopping power.

Anything that can be done to improve it would be great.

I'm planning to clean the rear caliper and maybe rebuild the rear master too.

What are peoples opinions on their bikes?

Tom B.

[skids]

I have two that will definately lock the front and back wheels with good tires. You can't get much better than that. I have one that seems to have issues with the front. I am going to sand/scratch the rotors and see if it helps friction. Maybe it is the pad type...they are pleanty thick. Perhaps I glazed them (?)

[John]

Tom, remember that you have the split/linked braking system, and when you squeeze the front brake lever, you are only applying one caliper. The rear master will apply the rear brake, and one front brake at the same time. Plus the Roadstar probaly has modern multi piston calipers vs. the single piston/dinosuar technology of our bikes

[Pat Kelly]

My 1st emergency stop was with the original 25 year old brake lines up front. Ended-up in the middle of the intersection (fortunately no cross traffic).
Stainless hoses up front I can do stoppies if I work it. There are bikes (lighter) that will stop quicker but mine stops plenty quick.
I do have drilled rotors (cosmetic) and the Parts n More all-metal master cylinder but it was just as good with the original M/C.

[excess11]

Reply to Front Brake Problems

I would pull the front brake pads take a sanding block with 60 grit paper and skuff the pads up real good until they look clean and new.I think that your pads are glazed or fouled with something. Also try bleeding the brakes, any air will cause poor brake performance!

[tab1324]

glazed pads / rotors

How can I tell if that's the issue? Maybe the pads just need to be replaced with something better... I cannot now, or could I ever lock up the front brake even with a gorilla grip. Of course I never tried it about about 20 miles an hour.

I'm thinking the glazing may be the issue. The rotors are quite shiney. So if I roughen up the pads should I also sand the rotors a bit with some 220 grit or something similar?

I know I have the linked brakes and I've even looked in the Yamaha manual for the bike which says to use the pedal primarily and to use the handle (front) for extra stopping power. I use both all the time.

I've bled these things until the cows come home and this hasn't seemed to help. I also tried the thing about tying the levers closed overnight so that bubbles can escape (though I never understood that idea)...

The bike stops pretty quick but it seems to take a monster grip to make it do so. I don't think it's unsafe I just think it needs to be better.

Also, what about warped rotors? I think I may have one. Can they be machined flat? They seem plenty think when you compare to rotors on newer bikes.

Tom B.

[excess11]

Reply

You can skuff the rotors use a fine grit paper 220 should work good. You should sand them back and forth not around the circumference. A warped rotor would give you a pulsating feeling when braking and kind of shake the frontend when on the brakes.

[prometheus578]

If the brake lever feels firm, and doesn't pull all the way back to the handgrip, I'd suspect then the pads or the rotor are glazed

[DeanR]

Could someone please elaborate on the proper way to sand rotors. As I posted in another thread, my front brakes kind of 'buck' when stopping slowly and I'm thinking it can't hurt to sand lightly. Rotors are clean and not warped.

[TopCatGr58]

Well, Dean,

All I can tell you is that I had a nice layer of rust and corrosion on my discs from when the bike sat outside for 9 years, and I took a Drill mounted round wire brush to it pretty heavily to remove the rust and stuff, and they feel just fine, no pulsing and such. So..I doubt that you can do much damage with some hand sanding using some emory cloth, whether you rub radially from center towards outside edge, or if you follow the circle curvature of the disc.
T.C.

[excess11]

sanding technique

I think the purpose of sanding from the center out is to create additional friction to seat the pads. You really can't do it wrong though, just rough them up!

[tab1324]

I've got an electric DA oscilating sander. If I stuck 220 grit on there and went over the rotors, would this be acceptable? I just don't want to ruin them.

The one rotor I believe is warped because it does pulsate slightly - more noticable at slow speeds and coming to a stop. Can these be machined back to tolerance once their warped?

Tom B.

[fabriqueprecis]

Stainless Lines

On the stainless brake lines - what size lines are used -3 or -4? I have made up braided stainless fuel lines for cars, but have never made brake lines. Looks like the same stuff though - anything "special" I should know about? Earl's has zinc-plated steel banjos, tubes, nuts - everything for making brake lines. Seems pretty straight-forward.
By the way - the rear m/c on my '80 is not connected to either front caliper.

[TopCatGr58]

Tom,

The rotors minimum thickness spec is 6.5 mm, and I don't think they start out much thicker, so not much room for machining, and I do mean machining, you can't get them turned at your local auto brake shop, these are a much harder alloy than standard auto brake discs!! The warpage runout limit is listed at only 0.15mm You may be able to get them trued by a machine shop, but could be tricky with slotted rotors!? Just don't tell them the minimum thickness range!

Some others may be able to chime in with more info on how thin they would go...below the spec level and still have a decent safe strong rotor!?

Fabrique,
Randy makes these in sets, but not sure if he'd devulge his trade secrets? All I know is that the bolt/banjo hole sizes are 10mm!
T.C.

[fabriqueprecis]

Secrets...

Making up braided lines is a lot of work and the fittings and hose are expensive! Randys price is very reasonable considering all this. I've done a lot of fuel plumbing on cars, so I think I can handle it. I can get the size too, just thought maybe somebody already knew.

So many "secrets" are so freely available on this site, it's incredible!

I'd like to mention something about people buying used parts for these bikes on e-bay - new parts are still available from several sources - look around! Some of the used stuff is going for new prices!