I actually wasn't losing brake fluid!

sseres

XS650 Junkie
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My front brake has been squealing so I guessed the pads were done. However, I also noticed brake fluid in the master cylinder was low. I saw no leaks and I really wasn't in the mood to rebuild it or the calipers. I didn't think I should need to, as that'd been done less than 2 years ago.

I got all the parts to do the caliper rebuild, as well as new pads from Mikes. Here it is compared to what i pulled off my bike:

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Clearly I'd let those go down a little low. I had to push the piston back in the calipers before I could get everything to fit together. And then, Viola! My brake fluid was back to normal! No leak! Just a piston in the caliper too far out due to the shrinking pads! Whew!
 
I always flush my brakes when I'm doing anything else to the system. Change the brake fluid frequently, and the system stays much more reliable and clean. If you live in a humid environment or if your bike sees weather, it does not take long for it to absorb a significant amount of moisture.
 
What size is your rotor? That pad is worn far different than any I've seen. The front should be 11.5, a rear rotor is 10.5, the difference is 1.2, 1/2 that is .6. That's about how much pad not worn.
Leo
 
Looks like the pad fell off the backing plate, it didn't wear that far down. I've run across that several times. Happens with old brake shoes too.
 
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best pic of his front brake I could find. The rotor does look kinda small? AND it has a half and half look of shiny dull.
 
Ok, not sure how I missed that discrepancy. The brake pad definitely didn't come off the backing. I think there is a mismatch. Maybe PO had a reason to use a different sized rotor?

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Here's a close up of the distance between the edge of the rotor and where it hits the calipers.

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I assume I'm therefore missing some braking power? Honestly, I'd not noticed this before now.
 
Yes, it does look kinda small. The O.D. of the disc should about reach out to the top caliper mounting bolt .....

OldDisc.jpg


I'm always amazed at the things I see around here, lol. Just when I think I've seen it all, someone comes along with a bigger, better FUBAR, lol.
 
Mystery SOLVED. XSLeo wins this months stump the gurus contest!

Best guess is it's an XS650 rear rotor or Xs750 front as Leo sez. toss it and put onthe right size.
 
Using a different sized rotor is just plain wrong, there's no reason for it other than the P.O. screwed up.
 
On my bikes there is only about a 1/16 to an 1/8 inch between the edge of the rotor and the caliper bracket.
My guess is the po didn't know there was a difference in rotors.
Easy fix, there are tons of them around. If you shop Ebay try to find one that is slotted. some models had slotted rotors. Some also used 5 mm thick rotors, these are much lighter than our stock 7 mm thick rotors. about 28% lighter.
I'm using a pair of the 5 mm thick slotted rotors on the 75. The 81 has apair of the 7 mm slotted rotors.
I like the dual disc. A bit heavy but they work very well.
Leo
 
The stock brake rotors are pretty stout stuff. Not much goes wrong with them. All i've measured have almost zero runout. and they wear well. Except for the damage caused by yours being the wrong size is almost nonexistant.
I wouldn't buy used brake pads or old rubber lines but the rest, yes, calipers and mastercylinders are easy to rebuild. Kits don't cost much.
Most of the bikes as well as everthing else on the road is running on used parts. Even that brand new car you bought last year is.
Leo
 
Tell me about my new car! Did I get seat heaters? :)

I'm going to check out the classifieds here. Not a lot for sale on eBay tonight anyway..
 
I got 2 extra brake rotors with my SR500. I quickly saw that they were a smaller size but the seller stood firm that they would fit. Of course those rotors were about an inch smaller. A friend with an XV920 got them. I don't know why some people can't SEE something like this while others can.

You know sseres, you've got a nice looking bike so investing in new shouldn't hurt too much. I like dual disks as much as Leo. I love to be able to stop on a dime with little effort. Great strong brakes give buckets of confidence while riding. I think you need to get two light weight rotors and the left side caliper from mikesxs. You can use the stock master cylinder and the brakes will be super strong and super good looking. If you need new brakes hoses you can get the hard plastic lines with the steel braid over them but mine seem to work just fine with stock rubber hose.

Tom
 
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Tom: Sounds like good advice. How does the hose action work to drive the break on the new side? Is it just a splice or some kind of T-connector?
 
On your lower tree there is a junction block where the upper and lower hose join. To add the second line you just get a double banjo bolt. Remove the stock banjo bolt, add the new line install the double banjo bolt. Use all the necessary sealing washers of course.
When you searched , did you put XS650 in the search? Try Just XS, As in Yamaha XS front brake rotor. You will find more that way.
One seller has two XS750 Special rotors for $19.99 each free shipping. Just contact him first and have him measure the diameter. The Specials used a leading axle fork. These used the smaller rotors. The Standards used a regular fork with the larger rotors.
Another guy has XS1100 rotors that are slotted, 5 mm thick, $24 free shipping. They are not XS1100 rotors but do bolt right on. Again ask about the diameter.
He has pics of the bike they came off. If you look at the forks you can see what a leading axle fork looks like. These rotors won't work, they are the smaller ones.
Leo
 
I like a single disk with a smaller master cylinder (10mm) but most drop from the stock 14 down to 11 or 12mm, stainless lines and the Vesrah pads from 650Central all the two finger braking you are likely to need on the street. and um sseres; considering what you WERE running (without noticing) it will be plenty for you.
Madness has dual rotors, stainless lines and a stock MC I don't think it's better than the single disk set up I have on my 79 roadster. and at a big weight penalty.

Still haven't got a rotor miked sseres but in morning I think.
 
Thanks, guys. I was searching on xs650, not just xs. If the specials used the smaller disks, I wonder what's going on with my bike? Maybe PO used a combo of regular forks and a special disk? Whatever. I went ahead and got one of the new disks from Mikes because I also had some other stuff to order, so I'll swap that out when it comes in.

gggGary, I love the "considering what you WERE running" line! It's pretty humbling hanging out around here. I will see if I can maybe do a double disk set up on the 78 I'm going to be putting together next.
 
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