XJ550 Brake advice

A friend picked up a clean but not running 82 XJ550 Maxim on Friday. First problem we're tackling is the front brakes. When we got it, there was no fluid in the M/C, and some milky junk down in the caliper. The PO said the guy he got it from supposedly put the wrong fluid in, and that he had tried to bleed it and it wouldn't bleed.

Well, I got it to bleed using about a pint of fresh DOT4 once I finally quit trying to crack the banjo bolts, and just put my bleeder bottle on the caliper bleed screw. Got all the nasty fluid out of the bottom of the system, and most/all of the air out. Now the front brake is sticking on pretty hard. I can see the pressure release port, and it looks somewhat clogged... I tried using the smallest, sharpest objects I could find around the shop to free it up, but that didn't help. I haven't messed with the caliper yet to see if it could be a seized piston, but my gut tells me the brakes are stuck too much to just be a sticky piston. The pads were about 1/8" each off the rotor when I started.

So, what's the next step? Is there a better way to try to ungunk that port and hopefully allow the brakes to function right? And is there a better/newer M/C that could replace it and keep the 1/2" bore? The M/C on my XJ700 was nasty and got replaced with one from an FZ1, but that's got a 5/8" bore like most bikes. I assume using a 5/8" M/C with a single caliper would result in not enough lever travel or braking power?

 

A system that was that contaminated should be totally stripped and rebuilt. Chacal has kits for the MC and calliper. It is a good time to replace the lines with stainless, also available from Chacal. I replaced my fluid with DOT 5 after flushing the system. It is silicone based and won't harm the paint if spilled onto the painted surfaces. Also pull the rear wheel and check the rear shoes for de-lamination of the friction material from the shoes, a common problem.

 

Exactly. No shortcuts on brakes, and that's what you're contemplating. The system has to get stripped, you never know what you're going to find.

Properly rebuilt, and with stainless lines, the stock components are fine.

 

You're preaching to the choir. My bike has new calipers (old ones had sticky pistons), a new master, new pads, and will have new lines ASAP. But this isn't my bike, and I'm not the one buying parts for it.

The caliper definitely needs to be rebuilt or replaced, and the lines will definitely get replaced, probably with stainless lines. Brake shoes are on the list as well, unless I find nearly new ones in there.

But I'd rather replace the M/C than try to rebuild it- it needs a new lever, sight glass, and cap/rubber gasket thing on top of the cylinder rebuild itself. Besides that, wouldn't a rebuild still leave the pressure relief port clogged?

 

I use a single bristle from my parts cleaning brush, grasped in a hemostat, to poke the tiny port clean.

If there's gook below it keeping it clogged, it's in the bore itself.

Take it apart, clean it and examine the bore. That will tell you if it's even rebuildable.

Or get a halfway clean one for the same bike off eBay and rebuild that. Either way, the part that you end up with has to have new guts.

On the 550, the caliper WILL continue to hang up until you rebuild it. The parts are simple (2 rubber rings) but the CLEANING, which is absolutely vital, can be a pain in the arse.

You gotta do this right, or you will be at it for a while, doing the same stuff over, until you do. Explain that to the owner; it's gonna get done right eventually, whether you want to do it the hard way is up to you. The same thing applies to the carbs.

 

Tell me about it, I just got them torn down. They looked spotlessly clean, until I took them apart, then they're nasty filthy. To the point that the needle on #1 was stuck in the nozzle.

It's that military mindset, I tells ya! "If it looks clean, it must be clean" obviously doesn't work with carbs. :roll:

Guess he'll be picking up a couple rebuild kits and a new M/C cap and/or gasket.

 

To be honest, I think you should be putting your time, money and energy into getting the bike running first. If the engine is toast or costs a bundle to get running, rebuilt brakes won't do much good. Just sayin'

 

Good point. Has anybody run a compression test yet, to see if this is an excercise in futility?

 

It ran before I pulled the carbs, but only with the choke on. The PO had given up on it because it died whenever it was put in gear... turned out to be the kickstand switch.

Hopefully after a thorough carb cleaning it'll run right... or close to it.

 

Running is no garantee of a solid motor. You could have one "soggy" cylinder, and it could end up having you chasing your tail after rebuilding carbs, etc.

Do a compression test.

 

We'll get there. I've had the bike in the shop less than 48 hours, and I didn't much feel like looking at it yesterday after driving 12+ hours to get it Friday. :lol:

It's surprisingly clean for a 29 year old bike, and not in the "cleaned it up to sell it" way, and showed no signs of low compression, otherwise I'd have checked the compression already. I'm not too worried about it myself, so far he's spent a total of $0 over the purchase price on fixing it.

Hopefully once I pop the carbs back on, check the compression and valves, and take care of the front and rear brakes, it'll run like new. :twisted:

 

I got the brakes rebuilt yesterday. I'd like to thank you guys who said to rebuild them- I'm sure I could have just cleared the pressure relief hole, but I'm glad I didn't after seeing the crud in both ends. Way easier than I expected (first time rebuilding any brake parts, let alone on a bike), only hitch was the circlip in the M/C. Probably had been leaking a little over the years, as the clip was pretty well rusted in the groove.

While I'm at it, is there a good writeup on rebuilding the XJ700's dual piston calipers? Do I have to split the halves, or can one piston at a time be removed with it whole?

 

Good going, gotta rebuild 'em. New lines? If not, then SOON. They last 5 years. If those are the original lines, they're NOT safe.

You got things out of order in your previous post.

Leave the carbs off (makes compression test that much easier do the valve clearances before the compression test; and especially before trying to sync the carbs. Valves gotta be in spec before you try to do a vac sync or you'll go crazy.

 

Valve check, carb sync, and compression test are next, whenever the owner decides he wants to (and one of us buys a YICS tool, carb synchronizer, and something to remove shims, none of which I own). I took it out for a spin yesterday and it seems to run OK, but the top end isn't all there... not sure where the issue lies, since he wanted the stupid Dynojet needles and jets in it, and I just tuned the mixture screws enough to make it run.

Brake lines are coming very soon, whenever he decides what route he wants to go- lines from chacal, some other braided factory-setup lines, or switch to a long, single line. If you've got words of wisdom on that choice, I'd love to hear it, I don't exactly get why it has 2 brake lines and a 90 degree block on the fork.

 

The complex configuration of the stock braking system was a concession to manufacturing flexibility, as far as the junction block and all that hookey-poo. My Norton has one long line, M/C to caliper. But it wasn't part of a "family" of bikes, some with a caliper on the right, some on the left, some with dual discs, like the Yammies.

So you could switch to one single line; or duplicate the stock setup.

I'm running stainless lines with black covers I got from chacal; the uppers are shortened to go with a lower "Euro" bend handlebar.

You don't NEED the shim tool; look at "Part 2" of my valve adjustment how-to, which includes the alternative: http://xjbikes.com/Forums/viewtopic/t=29209.html

You can also block the YICS with a "rope" of oil-soaked rag; and build a simple manometer from 4' of clear tubing, a yardstick and some ATF. All of those methods have been covered on the site, many times; just do a forum search.

You're not going to get any serious performance from a 550 until it's properly tuned; then it will run like a scalded cat. But out of spec valves, a low or high float level somewhere, or seriously out of sync carbs and you WILL NOT get any sort of decent rideability from it.

Get it right, and it'll pull redline in all 6 gears. But you gotta do it right or it won't. Tweaking and fiddling won't do it. Wanna guess how I know? (See below.)

 

Well, I think I found the source of the poor upper end and loud exhaust. Who knew the mufflers aren't supposed to have 4 3/8" holes drilled in their end caps? Whoever did it did a good job, they look stock!

Any reason not to go with the "build your own" Goodridge lines & fittings? They're pretty attractively priced if you cut down to the minimum number of lines required.

 

Im havin a real bad problem with my XS1100s brakes too. Super gunked. Wondering how to remedy the problem.

 

The rebuild was incredibly easy... and I'd never rebuilt any brake parts before, let alone motorcycle brakes. Since it had a single, single-piston caliper, I just pumped the brake lever (with the caliper off and pads out) until the piston popped free, and caught the fluid with a rag and catch can. With multiple calipers, or multi-piston calipers, you may have to resort to the grease gun trick to pop the pistons out.

The M/C has a circlip under that rubber 'seal' that needs to be removed, and it pretty much comes out as a unit once the clip is removed.

I used 000 steel wool, and used my impact driver to spin it in the bore of the caliper and M/C. Just be sure not to let whatever bit you use touch the sides, and use one that's dull and soft if you're gonna try it. Ideally you'd want something like those rubber sanding drums for Dremels, minus the sandpaper, I just used a screwdriver bit since I didn't have that. We got lucky, the caliper piston was in really good shape and just required a little touchup with the steel wool.

Then lube the new parts and the bores with fresh brake fluid, install the seals, and insert the piston in the caliper, and the assembly into the M/C and install the circlip.

 

Thats the thing, i cant even build pressure with the brake lever. Wont happen. I Got a mighty Vac and THAT wouldnt even create enough pressure to suck anything out. Might have to rebuild the MC first, pump, and pop.