Better braking

I've been riding with people that have newer bikes lately and I'm finding the XJ lacking in a few areas. First, most all of them can out accelerate me, which really isn't so big a deal 'cause I can kill myself real quick with the power I have. Second, they have a bunch more rubber on the road, but so for I haven't found myself pushing the tires I have to hard. Their six speed tyranny's would be nice but that's not a real big deal. The one that gets me though is the brakes. Everybody with a bike from about 1985 on can out break me and most by a large margin. If I don't lave larger following distances or set op for turns sooner than the others would, I'm going to be in trouble.

I have replace the lines with steel braided and the master cylinder has been rebuilt and the system totally flushed. I think the lines helped, but it was a long time between riding it with the old lines and the new. I've considered having the rotors drilled, but I'm dubious that it would help much. I'm also still using stock pads and think that there has to be something better. I wouldn't mind changing them often if it would slow me down quicker.

Do y'all have any good pad recommendations or any other ideas I should try?

Thanks,
Mike

 

You are never going to make a 25 year old bike handle or stop like a new bike but when I replaced the lines and pads that gave me all the braking I could use. Once you can get the bike to come up on the front wheel with just 2 fingers you can't go any farther. I sometimes think the chassis should be longer so the rear wheel will stay on the ground because the rear can only provide some stopping power when it stays on the road. I drilled the rotors too but that doesn't make any difference in stopping, just makes it look cooler. However you need to sand the disks smooth if they have ridges and grooves in them and are uneven. If you only have one front disk you will need two for the most stopping power.

 

There's no way I'm coming up on the front wheel with two fingers on my bike. If I was to grab a handful of brake lever maybe.

These are likely the original brake pads. They are not glazed but they could well be hardened after so many years of sitting around. Anybody got a favorite brand or type that they like?

 

I use whatever pads are cheapest on ebay and they work fine. As long as they are fresh and not 25 years old and soaked with oil and brake fluid they should be fine.
You could use just one disk if it was a really big one and you fit a 4 pot Brembo caliper like on this 650 Jawa.
www.f2motorcycles.ltd.uk/jawa.html

 

I'm sure you could custom fit a 3 piston sportbike caliper. Shouldn't be to difficult. , and it would give you tons more stopping power. You could alway's experiment with a larger diameter rotor as well. Might be tricky finding the same bolt pattern though, and you would probably have to relocate your caliper anyway's.

Cheesy!

 

I've used the EBC brand organic pads and they work just fine:

Disc Brake Pads:


bp4) Quality OEM and aftermarket Disc Brake Pads restore proper braking action. Organic materials provide exceptional brake lever or pedal "feel", while being gentle on the rotors, and also providing excellent stopping friction.

HCP1708 Aftermarket EBC brand organic front disc brake Pad Set, enough to do one front caliper. Fits all XJ650 Seca models. Each set:
$ 32.00

HCP1708SET2 aftermarket EBC organic disc brake Pad Sets, two sets of pads does both front calipers on XJ650 Seca models front disc brakes. Per set:
$ 59.00


However, I would also make sure that you pay proper attention to the other parts of the brake system, too:

a) make sure the Master Cylinder is operating properly, rebuild it if at all suspect. Make sure the small fluid pressure relief port in the floor of the master cylinder is clear.

b) make sure the brake calipers are operating properly, rebuild if suspect.

c) check the rotors for thickness, runout, and make SURE there are no hairline cracks, anywhere, but especially around the bolt holes and along the outer circumference.

The factory dual-disc bikes stop pretty well. More stopping power is nice, but can become expensive quickly, and too much stopping power is---unless you're into the stunt-riding thing----risky. You need MAXIMUM stopping power in a panic situation, not OVERWHELMING stopping power that is unstable, unusable, and can easily make a bad situation worse.....

Other thoughts, ideas, and parts over at:

http://www.xjbikes.com/Forums/viewtopic ... t=135.html

 

Thanks for the replies. I got myself into trouble tonight and I really don't think these brakes are up to par. I don't think I could lock these things with two hands!

I considered transplanting some different calipers but there would likely be a fair amount of machining involved to adapt them. I doubt I would find rotors with the right bolt pattern and offset.

The master cylinder was thoroughly cleaned and rebuilt a short while ago. The system had been heavily contaminated, so I changed the lines and completely flushed the system. The rotors have been inspected and there is nothing there that I think would cause a problem, other than I'd like them to be bigger. I think I'm going to order some pads, and possibly kits for the calipers and flush the system again. Based on what Steve is saying his will do, mine is definitely not close.

Mike

 

Just adding a progress report. I got a new set of EBC brake pads from Chacal and installed them a couple of days ago and I completely flushed the system for the second time. I also inspected the master cylinder again for cleanliness and function with no problem found and reinspected the rotors which have minor grooving, but nothing out of the ordinary. I may have a little better feel from the new brake pads, but I certainly have no better braking. I do want to find and compare the ID of the stainless lines I bought to the stock lines. I'm wondering if the new ones might be smaller.

Steve says he's able to bring the bike up on the front wheel with two fingers which sounds to me to be about as good as any of the newer bikes. I'm able to stop the bike, but cannot lock the front wheel at all and it really doesn't make any difference if I'm using two fingers or a whole fist. The lever feels very firm and has no perceptible fade.

I'm interested in whether or not any others readers are able to reliably lock the front brake.

I have looked into after market solutions some, and have some possible solutions, but I'm hesitant to go there because of cost.

Any and all experiences appreciated.

 

This is just a LONG shot...but is there any chance someone changed the master cylinder to a different size (piston diamter).
Your braking power comes from squeezing a "small diameter" cylinder of brake fluid into a larger diamter caliper cylinder. The ratio of these two diameters produce the sqeeze on the brake pads.

I'll use fictional numbers, but try to explain my point:
If the caliper is 40 mm and the master cylinder is 10mm theoretically the caliper would move .0625 mm for every mm of master cylinder travel.
(it's a function of surface area of the cylinders)
If the master cylinder was designed to push a larger caliper than what you have the potential pressure will be less.
The other thing that will affect your potential pad squeeze is something as simple as the length of the brake lever itself. A brake lever that is 8" long will produce much more pad pressure than a 5" brake lever.

These are just a couple things to check and consider (if you haven't already)

Good luck
Mike

 

The Brake lever has been changed but I used an OE lever.

Mike,
I understand what you are getting at and the single disk brake bikes did use a master cylinder with a different bore. I think my master cylinder is original because when I rebuilt it I ordered the OE kit and it fit fine and builds pressure well. The lines have been changed though, and I had wondered if the ID could be smaller on the new ones. Since both you and I are on the same track, I think that may be worth pursuing. Are you able to lock the front wheel, even from slower speeds?

Does anyone know what the OE brake line ID was?

Thanks,

 

The diameter of the line would only affect the speed that the calipers clamp down and shouldn't affect the maximum pressure. If you look at the brake lines on a car, they are tiny (many are 3/16" OD)

Is there a single line straight from the master cylinder to the caliper or does it go through a splitter or splice of some type.

It will probably take a little while for a new set of pads to "seat" onto the disc and give the best stopping ability. It might be a good idea to get the disc ground smooth...it may be glazed a bit.

You can also adjust the lever position a bit (my X has an adjustment screw on the handle) to allow you to squeeze it closer to the handlebar before it really bits down. Your grip is stronger closer to the handle...but you also need enough clearance so you don't bottom out.

 

Well, I don't know for all the bikes, but I assume they are the same.....I have an original line of a 650 Turbo model that was cut in half during removal, and the ID of the brake hose line to the caliper is somewhere around 3.40 - 4.00mm.....hard to get an exact measurement, as the passage is sorta egg-shaped, but that should be close enough.

 

Chacal, I appreciate you checking on the ID, but the more I thought about it Mike is right. The ID of the hose would affect volume rather than pressure. In this case the volume needed to clamp the pads is very low so there's not likely to be a solution in that direction. These pads do not have enough millage on them to be properly set, but my experience tells me that any improvement will be minimal. These rotors are in pretty good shape. I'll be putting a bunch of miles on it this weekend and I'll report back if it makes a difference.

There is a splitter in this system. A single hose leaves the master cylinder and goes to a distribution block and then two hoses go to their respective calipers.

I got to ride a 1982 Seca 750 today that was owned by someone who has posted here. This was just a short jaunt around the block and I didn't push it for a variety of reasons. The back brake was worn and was not nearly as effective as mine but we knew that from looking at the adjuster before I rode it. Even though I didn't give them much of a test, I must say I wasn't terribly impressed with the front brakes on it either.

Maybe I'm just not a 25 year old brake kind of guy.

 

Mine brakes like crap too (82 650 Max.) but under no circumstance would I want to lock the front brake up anyway... thats a painful accident waiting to happen! I'm pretty handy with the revmatching downshifting and braking at the same time and I'm able to stop pretty well. I lock the rear from time to time but thats not a big deal as long as your ready for it.

 

Braided hoses can make a HUGE difference. Your hoses are probably expanding under pressure. Doesn't take much expansion to screw things up.Yamaha recommends replacing the hoses every couple of years.
I've seen them @ Dennis Kirk I think .

 

.... my brake pad have brass chips in them. my machine shop instructor at school said that they are not good because they do not wear like other pads and require more force to get the same amount of stopping power.

when braking, i can almost bring my lever all of the way in ON GRAVEL!
i need better brakes/pads bad

i am still running rubber hose, and my lever is still very spongy (i am making parts in shop to convert it over to steel line down to the distribution block)

does chacal have pad for a 82 xj550 that do not have brass chips in them?

 

Turtleman, all of the OEM original and aftermarket brake friction material has the small metallic particles in them....perhaps brass, perhaps some other type of material (I'm actually not sure). Until you get into racing-type brake pads, it's doubtful that you will find any other type!

The spongy feel is probably due to air in the system, perhaps exaggertaed by the worn out rubber brake hoses.

If you use a real metal hard line between your master cylinder and elbow joint (on the steering bracket), you may have difficulties in the future should you ever try to adjust the handlebars, etc. The flexible line is used for a reason between those two points!

 

I recommend against manufacturing the metal lines. The normal fix for this is to replace the lines with steel braided lines. There will be a noticeable improvement in your braking. There are a few vendors around that supply them, I don't remember where I got mine at the moment. another possibility that CHCAL didn't mention is that the plunger in the master cylinder could be bypassing some fluid. I'd start with bleeding and flushing then change line and if the lever is still soft rebuild the cylinder. It's easy to do.

My comment below about locking the brakes was rash. I should have worded it something like " a stoppie is absolutely out of the question". I gauruntee that my front will lock on gravel though, but I'm not going to tell you how I know!

I did a fair amount of research after I posted this and I never followed up. If I can get some time I will.

Mike

 

The brakes on these bikes are not known for being spectacular, even when comparing them to other '80s bikes. Compared to newer bikes they suck. Plain and simple. My maxim started out with the stock single rotor and then I upgraded it to the seca turbo twin setup. It still sucked. I had stainless lines, new pads, and a better master cyl and it still sucked. Now I have a honds vfr front end on the bike. I am expecting much better braking performance.

Also there is no way you are going to bring the back wheel up with two fingers on an xj with a remotely stock setup. I had the seca turbo setup on my bike and it wouldnt even lift the back wheel. Thats the largest brake setup on an xj and it was a 650 maxim which is about as light as you are gonna get for a 4cyl xj.

 

my maxim and virago had horribly spoungy brakes... i ended up flushing them with new fluid.. one of those air pressure powered bleeders work wonders for getting fresh fluid in there. Theyre like 15 bucks at harbor freight too!


The biggest thing i suggest is to loosen up one banjo bolt at a time and give it a bump.. tighten.. let go of lever... just use the banjo bolts like bleeders and thats the only good way i could get a firm lever and responsive brakes.... If its not that, you got a problem with something in the system.. but i bet its just air.. try it!


About lifting the rear wheel... im sure its possible with our spongy forks.. With a good enough front tire i bet it would.. especially with some weight leaned forward... i know 90% of cruisers will just lock up the front tire.. i know my max doesnt feel like its going to lift the rear.... 2 finger stoppie? Is that really required?!? or even remotely safe? (unless a pro)

 

Braided steel lines, caliper rebuild, MC rebuild. Stops pretty good and has a good feel to it.

 

I always found that if a caliper piston is slightly skewed in the caliper body it would still brake but have very bad 'feel'. Remove the caliper and pads, then press the piston/s back in all the way, making sure they stay straight. It may help to undo the bleed nipple but you need to bleed the brakes afterwards. Install the pads and caliper back on the bike and pump the brake lever to make the pistons come back to operating level (you may have to pump it several times). Long shot but worth it (it's free) :wink:

 

eliminate the cable over hydraulic setup and put a master cylinder from an ATV on it. thats what i did

 

Don't think he has a cable in his system.

 

My 81 XJ650 has had a warped front rotor that really makes the lack of stopping power noticable. I pulled the wheel and plan to change the rotor, but I have a question on the pads and my caliper. The pads are only partially worn, but they are tapered - thicker on one side and thin on the other. Is that they way they come new or is my caliper out of alignment and causing improper wear?

 

That is the way they are on the XJ650 models.............looks odd, is odd, but is "correct"!

 

Or, you could upgrade: Stainless steel lines, EBC drilled floating rotor and pads (from chacal.) Stock caliper.

 

"Floating" rotor Fitz? How the heck is that possible, isn't it bolted right to the wheel?

 

Attack 25 Year Old Poor Braking with a "System-atic" approach.

Bleed the System CLEAN.
Evacuate the Master Cylinder. Clean it out and dry it. Refill wil fresh Fluid and begin forcing New Fluid through the System until what is coming out is as clean as what you are putting in.

Is the Master Cylinder OK?
While you are pumping the New Fluid through the System, the Master Cylinder should pushing the New Fluid through the Lines.
If the Master is lazy about it ... the Master might need a Seal Kit.

The Master Kits available vary.
Some are complete Master Cyl guts. Others are just two Seals and a Spring.
New Seals in the Master Cylinder will inprove Braking. But, if the Master Cylinder Bore is pitted; they won't. You'll have to deal with the Bore, first.

Keeping the Master Cylinder Seals health in New Fluid, replacing the old Brake Lines and replacing Pads WELL Before they are 50% used will keep you stopping relatively well.

The Calipers on the Early Bikes are examples of innovation. None can be considered "Performance" Brakes.
Not until your calipers are the Live Twin Opposed Caliper Pistons are you dealing with a Caliper that can bring a Bike to a screeching halt.

The Brake Lines and Master Cylinder being in Tip Top Shape is where you start.

 

Maybe Im lucky.

But after I bought my new MC from Chacal and new brake pads, flushed the system out until it was running clean fluid into the jar, I definitely can lock my front wheel up, did it just before I tore her down last Fall, thanks to an indifferent lane change by a gal in a cage.

 

ok guys. I'm still trying to get my 81 xj650 road ready. i replaced the master cylinder with a magura 13mm one. i know the one i took off was a magura but im not sure what size it was. Its not working properly. my roomate said that what i get for buying crap. I would love to not have wasted 100 bucks because they wont exchange it for me. we flushed evrything out, the pads and rotor are good. Does anyone have any idea what the piston size is stock and where i can get something that will work without ordering an oem. help me please im tired of watching it collect dust.

 

The caliper piston for the XJ650 Maxim models is 1.70" diameter, the stock master cylinder piston bore is about 13mm diameter.

 

No, it's not. The rotor CARRIER is bolted to the wheel; the rotor "floats" on those round bushings you see between it and the hub; they have wave washers to keep everything under tension but the rotor itself is NOT solidly mounted, it "floats."

The complete upgrade of SS lines, floating disc rotor and new EBC pads made for a complete transformation of this bike's stopping power. It stops RIGHT NOW with very little actual pressure at the lever, and is still very controllable and has excellent feel as well as being fade-free.

I did a less expensive upgrade to my '81, see: http://xjbikes.com/Forums/viewtopic/t=1 ... art=0.html and ended up putting SS lines on it too, that WAS the single biggest improvement. The '81 stops very well now too, but requires a bit more effort at the lever than the one with the EBC full-floating rotor.

Stainless lines along with freshly-rebuilt everything else stock will improve braking power considerably, with just that one mod.

 

THANKS CHACAL!!!

i will tear it apart and start over with the one i have first.

 

mine stops like crap also,but someone has changed the master cylinder and I'm not sure what it is.

 

i run SS lines and a bar mounted M/C from a fj1300 fresh DOT4 and regular cheapo pads and 2 fingers to lift the rear wheel is very simple but it's also very simple to control i love it

 

so has anyone found a bigger rotor for xj's?

im thinking of a single disk setup with bigger rotor, sporty custom fitted four piston caliper, braided steel line and a bar mounted m/c?

or would the better caliper provide enough braking power for a single disk setup with the ebc floaters maybe?

plan is to lighten my xj as much as possible anyway so this single disk setup could be sufficient.

im getting some bad vibes from the front under braking. i think the other or both disks are a little crooked. i thought of having them straightened with a lathe(?), but theyre only 5mm thick. minimum thickness was 4,5mm i think. how thick are the new ebc rotors?