81 XS 1100 Start

[excess.11]

From the pic i see of you on the bike............it appears you have brake assemblies along with the front end.....off a "Standard" model .
The rear i can t see so you ll have to let us know on that one.........is it the same as the front ones?

On the 'Standard "model bikes/brake assemblys..........one other item to check for is the "PIN SLIDE'.
There is "One" bolt holding the caliper to the mounting bracket.

It passes through a  metal sleeve......... which allows the caliper and pads to laterally slide on a  rubber bush/grommet.

Theres the catch.........most don t allow the caliper to slide and centre itself on the disc when applying the brake due to being dried out and not lubricated.

"Do not "...use any solvent or petroleum based sprays to lubricate the rubber.........take it out and wash it in hot soapy water
(to push the sleeve through the rubber...to then get the rubber out.... ....... insert a screwdriver and work the sleeve in a circular motion ...whilst pushing it through)........then apply a liberal amount of "Rubber Grease".........found at Supercheap or any auto shop.......through and in the reservoir ends of the rubber as well as on the outside of the sleeve ..reinsert the metal sleeve ....and reassemble the caliper onto the holding bracket.
This is a regular maintainence item to attend to (2 or 3 times per year) ..........as they dry out and freeze the lateral movement of the caliper /pads over the disc.

[petejw1966]

heres a pic of the front being bled,
same for the rear



just have some fresh brake  fluid in the bottom of the jar and make sure
that the hose stays in that fluid, then u can pump the pedal away
being sure not to run out of fluid in the reserviour, if u do run out of fluid
u might then need to bleed the master cylinder.

[petejw1966]

hard to tell without looking at it,
take the pads out and have a look at them,
scruff them up a little on some flat concrete
put them back in and rebed the rear brake.


i had a similar thing on my busa when i first bought it
the guy had replaced the pads without bedding them in,
it had bugger all rear brake power, took it up to speed
and rebed them in, wworks fine now.

btw im a mechanic by trade.

[excess.11]

Brett, when bleeding the back brake..........many people make the mistake of  repeatedly pumping the pedal .............and wondering why no fluid is being pumped through the bleed nipple.
 
The reason why...... is best explained when comparing bleeding the front brakes to the rear.
When bleeding the front brakes.......you have a vertical brakeline...from the master cylinder which allows gravity to assist in bleeding from the master cylinder all the way down to the caliper pistons .

With the rear brake setup........If you look at the rear master cylinder in relation to the rear brake caliper...they are horizontally in line with each other ...........gravity "IS NOT" going to assist you here .

As long as all your plunger seals and brake components are in good order.........you " MUST" allow a "SLOW" count of "5" inbetween each push on the brake pedal to allow the fluid in the master cylinder to "RELOAD" in front of the plunger before the next push.
Obviously have the nipple open on the push down phase with a clear tube attached into a half filled jar of fluid.....and while holding it down..... close off the nipple......then release the pedal................count to "5" slowly..then repeat.
This will inject a small amount of fluid each time you carry out a pump down.....and will result in fluid being slowly pushed along the line and filling up the piston reservoir.
You shoud see bubbles in the jar of fluid on each push.......if not.....you most probably need a new set of rubbers seals on the plunjer in the master cylinder.

Repeatedly pumping at a quick rate....... will result in pumping and sucking a small amount of fluid virtually forwards and backwards........ with out allowing extra fluid to flow down in front of the plunger for injection into the line.
It s like the Tortoise and the Hare......"slowly but surely ....will win the race.

Many people have been frustrated with bleeding their brakes and coming up with pressurizing the master cylinder..or other ad hoc remedies....when all they had to do was either fit a new master cylinder kit......clean out nipples .....clean out the piston reservoir and seals at the caliper and simply allow time inbetween each push.

[Eveready1100]

Brett, Just wondering if you've had the caliper off at all? If the bolt that the caliper slides on is corroded, it may cause the brake to feel a bit that way due to it using the intitial movement of the pedal to flex the bracket over till the pads start to squeeze the disc. Just takes 5 minutes to check this. If it looks ok, have a check of the pads, as Pete suggested. They might look ok, but at some time in the past, might have been splashed with oil etc, which will badly affect braking power. A fresh set of pads might change the feel altogether. Also could just be swelling of the line, which as PGNZ has said, isn't a huge problem with the amount of engine braking you get from these bikes.
A quick deglaze of the disc surface (both sides) with a very fine grit flap disc (lightly) wouldn't hurt either. Just take care to rotate the disc smoothly while doing this.

[BrettS]

I don't promote myself as a experinced mechanic but I have bled the brakes to what I believe is a good or as good as can be standard. (it is only a small brake line)They still seem a little spongey to me but I am unsure and I am looking forward to getting the advice of other xs1100 riders. Like I said last time I checked I could not get the bike to skid with the back brakes out the front of my house. But I have had a lock up or two from selecting a gear too low for my speed.  Will muck around a bit more though?

[petejw1966]

So what would you suggest is going wrong with the back brake Pg? I will experiment with the back brake a bit more but last I checked at say 30kmh I could not lock up the back brake.
[/quote



have u got a solid brake pedal?
if so
what pads are u using?
whats the condition of the disc (is it glazed?)
take the bike up to speed and do some heavy hard rear  braking and get some heat into the pads,
sometimes if the rear brake is used lightly it can cause both the disc and pad to glaze up.

if the pedal is soft or spongy then it will need further bleeding.

[BrettS]

So what would you suggest is going wrong with the back brake Pg? I will experiment with the back brake a bit more but last I checked at say 30kmh I could not lock up the back brake.

[pgnz]

That back brake ain't working properly because XS11 back brakes are way powerful,  too easy to lock up and chatter the arse- end as it is(bad news in an emergency panic stop)  the XS11 rear hose setup is 1/3rd steel line anyway,  no way do want steel braided back there as well,  feel's what's needed for a back brake not power,  rubber hoses are better at the back,  braided for the front where you want all the power you can get

[BrettS]

Thanks Peter,
No Jonesy I am a slacker and I haven't done that yet. I have sourced where I will order from and which ones I need, keep meaning to buy a magnet of eBay. But I promise it is at the top of the things to do list. 

[Jonesy]

Hey Brett,
Just out of curiosity, have you got the valve shims all sorted yet? I remember there was one of the inlets with no gap ie valve always cracked open slightly. Adding to the lack of performance

[petejw1966]

dot3 or 4 is fine in our bikes,
the dot5 is used in later model vehicles
its synthetic and wont mix with the other brake fluids,
it causes the rubber seals to swell and soften.

[BrettS]

I used the standard fluid that I use in the car, I believe this is Dot4. Then the guy at the auto shop suggested it should have Dot3. When I noticed the resivour said only dot3 I thought I better get the right stuff. What is dot 5 used in?

[petejw1966]

hi bretts,
when u say u used the wrong brake fluid
u didnt use dot5 by any chance?
dot 3 or 4 would both work fine,
dot 5 is synthetic and will cause the rubbers to swell and soften.

[BrettS]

I did see that, now I read it better it does look good. Thanks