Brake rebuild questions 79SF

[XS1100_OEM4ME]

My 2 cents

My 2 Cents worth would be yes The bore dia. is matched to the caliper bores. The larger M/C bore means more volume / less PSI Smaller bore = more PSI / less volume of fluid. The OEM M/C is matched to the OEM calipers needs for both lever travel and feel (and look). The stopping power is determend by the m/c piston / rotor dia, sizes and pad material (Unless your grip is very week, the bike will stop in the same distance with the OEM m/c, you just squeeze harder with the OEM) Once in a panic stop on my then brand new XS750, I lifted the rear tire off the ground I hit the brakes so hard All the spongey feel in our brakes comes from the rubber lines, so your best fix for your dollar IMHO would rebuild the stock M/C's add the S/S lines and put on good quilty pads (not super aggresive, the rotors are not the high preformance racing rotors required for those) I use stock compound EBC and they work great and are quite on my bike

so the best combination would be---rebuild the oem master and add braided lines??! Am I correct?

[crazy steve]

It does make a difference because with more leverage you can put more clamping force on the disk. More clamping force means more friction, more kinetic energy transformed into heat, and thus more stopping power.

Yes, that's true... but what you're not taking into account is the limitation of the bike balance and the amount of traction available at the front tire.

The stock master already produces enough pressure to lock the tire up and/or pitch you over the bars, so applying more doesn't do any good if you can't use it. You might gain some slight additional power with organic linings once they start to fade, but that's it; and it'll only be temporary until they overheat more.

To get meaningful improvement in braking performance on these bikes, you need to dissipate the heat faster; larger pads, more swept area on the rotor, and/or slots/holes in the rotor to allow outgassing and more surface area for cooling.

[sthomag]

My 2 Cents worth would be yes The bore dia. is matched to the caliper bores. The larger M/C bore means more volume / less PSI Smaller bore = more PSI / less volume of fluid. The OEM M/C is matched to the OEM calipers needs for both lever travel and feel (and look). The stopping power is determend by the m/c piston / rotor dia, sizes and pad material (Unless your grip is very week, the bike will stop in the same distance with the OEM m/c, you just squeeze harder with the OEM)

I couldn't disagree more. The XS11 MC is badly matched to the calipers. It doesn't have enough leverage to make the calipers grip the disks as hard as they could. That's why it feels lousy.

A 17mm MC gives much better feel and more power because it gives better leverage. A harder grip means more power. That's why cars have POWER brakes: so the calipers can grip the discs as hard as they should. That's why when you squeeze hard on the brakes, they stop more quickly than if you squeeze only a little. The limiting factor is fade from heat buildup, which shouldn't be a problem in normal riding with modern pads.

By telling oldskool that a different master cylinder won't make a difference in braking power, you are giving him bad advice, advice that goes against common sense and physics.

Also, stainless steel lines work better because they don't expand. When rubber hoses expand, they limit the pressure applied to calipers, thus reducing POWER.

[XS1100_OEM4ME]

+1

+1 Steve. When working correctly, the stock brakes can lock the tire (I know, I have done it) so no improvement in stopping distance with other componets. If you ride like a pro bike racer, then you will need new high preformance everything and 30 year old OEM componets cant take that kind of heat and abuse Old Skool has said in past post, he is againest any kind of crazy or unsafe ridding, so a stock system with upgraded S/S lines and good pads would the best fit and $$ IMHO Also the extra feel of the OEM Front M/C is kinda nice in rain and slick conditions as it is harder to accidently lock up the tire

Yes, that's true... but what you're not taking into account is the limitation of the bike balance and the amount of traction available at the front tire.

The stock master already produces enough pressure to lock the tire up and/or pitch you over the bars, so applying more doesn't do any good if you can't use it. You might gain some slight additional power with organic linings once they start to fade, but that's it; and it'll only be temporary until they overheat more.

To get meaningful improvement in braking performance on these bikes, you need to dissipate the heat faster; larger pads, more swept area on the rotor, and/or slots/holes in the rotor to allow outgassing and more surface area for cooling.

[old_skool]

Ok, you guys agree to disagree, I understand both philosophies, Quicker response is only as good as the braking system it has to do the job, So I understand what Steve is saying also. Believe it or not, your both right in different ways, I will take both of your vary knowledgeable inputs and go from there....oh yeah...you too OEM, just kidding, I appreciate the advice from everyone. I think the only real debate is whether the oem braking system has enough to do the job with its current calipers...I will rebuild my MC, upgrade to braided lines, then try a newer MC after and decide from there. Thanks Everyone!!

[sthomag]

Yes, that's true... but what you're not taking into account is the limitation of the bike balance and the amount of traction available at the front tire.

The stock master already produces enough pressure to lock the tire up and/or pitch you over the bars, so applying more doesn't do any good if you can't use it. You might gain some slight additional power with organic linings once they start to fade, but that's it; and it'll only be temporary until they overheat more.

To get meaningful improvement in braking performance on these bikes, you need to dissipate the heat faster; larger pads, more swept area on the rotor, and/or slots/holes in the rotor to allow outgassing and more surface area for cooling.

I've never come close to "pitching myself over the bars" at any kind of real speed, or "locking the tire up" on my XS11. I can bark the tire easily at low speeds. If you can do that at highway speeds, I'd like to measure the circumference of your forearms.

As far as "meaningful performance," I've yet to find a problem with fade on these bikes during one panic stop -- or hardly ever, for that matter. Maybe going downhill in the mountains. To get "meaningful improvement" in stopping distance, you need more pressure on the pads. That's it. You get it with more leverage at the master cylinder. The calipers can handle the extra pressure without flexing too much also, by the way.

I'll say it again. You are dispensing bad advice.

[old_skool]

One more thing to note guys, I didn't mention it on this thread but as some of you know from another thread, I plan on pulling a light trailer from time to time at least several times this coming summer.

[crazy steve]

...To get "meaningful improvement" in stopping distance, you need more pressure on the pads. That's it....

I'll say it again. You are dispensing bad advice.

Hmmm, so you're saying that all those 2,4, and even 6 piston calipers seen on various bikes are unneeded? Larger pads and rotors are a waste of time? Maybe we should go back to drum brakes, as those were 'self-energizing' and that would reduce the need for higher line pressures even more...

As to my 'bad' advice, I was merely pointing out the differences in the various options.

[XS1100_OEM4ME]

Trailer

I have never done that but as long as your total weight doesn't exced the max for the bike (set in part by the brakeing limets of the bike) I would think you should be fine. I think you said something about makeing one your self? I would just make sure you get the aerodynamics right. I sall a guy yesterday pilling what looked like a big box, no aerodynamics at all, and worse yet, the thing tilted upward in the front

One more thing to note guys, I didn't mention it on this thread but as some of you know from another thread, I plan on pulling a light trailer from time to time at least several times this coming summer.

[James England]

All good advice frome the other members. It sounds like you would rather be safe then sorry, so I would get new kits all around, not that much cash for all new brake parts.

Agreed. I did just that. I would buy master cylinder kits and renew all the seals in all three calipers. Then you know it's done, don't you? I ride mine about knowing that the brakes are all done as they should be, and were done at the same time. It's a reassuring feeling.

[crazy steve]

One thing I'll note that when working on Special calipers is make sure the 'retainer' is there (part #10 on the parts fiche), I tried to show a pic but it wouldn't come up...

These get lost, and the problem is the pads end up resting against the aluminum slider. The pads will wear grooves in the aluminum over time, and this can cause issues with the free rotation of the caliper. As a worse-case, if yours are missing you could fab a small steel 'angle bracket' and attach it to the slider for a wear point.

[old_skool]

gotta teach these guys everything....lol

[crazy steve]

Yep, that's the part....

[XS1100_OEM4ME]

#15

#15 is the bolt I said to check to see if bent at all. If so, the caliper will wobble slighty when removeing the bolt, easy cheap fix

[James England]

That's why it feels lousy..

It doesn't though. The braking system on an XS1100 is perfectly adequate for the performance and the type of bike that it is, I'd say. I bet you didn't grow up with this era of bike, did you? If you've bought an XS1100 and been used to riding modern bikes, no wonder you think the brakes feel "lousy". I think what you mean is "non-modern". It's a different thing and using terms like that to describe aspects of classic bikes isn't really valid, I'm afraid.

Incidentally, it's easily possible to lock both front and rear wheels using the OEM brakes without having huge forearms. The rear is dead easy in particular. As has been said, the whole thing depends on traction of the tyre on the road. Super-dooper modern brakes will stop the wheels rotating better but look at the 'footprint' of an XS11 compared to the huge tyres on modern bikes; there's a lot less square footage in contact with the road.