Condition of Front Brake Caliper (Two-Piston Type)

[YL82]

Can calipers be cleaned up? Solvents and/or wire brushing? When is caliper replacement warranted?

I plan to replace the pitted pistons and install new seals.

 

[5twins]

Yes, calipers can be cleaned. Yours don't look that bad. In fact, the seals and pistons don't look that bad either. What you have to realize is, once pressurized, the piston doesn't move in and out much. As long as those pits on the pistons aren't in the area that moves through the seal, they'll be fine. My advice is to clean everything, re-assemble, and see what happens. If no leaks then you're good to go. That's all I did with mine. It locked up and didn't work when I got it. Now it's fine for years so far after a good cleaning - and no replacement parts.

 

[YL82]

Sounds good to me. These parts are off of my latest '76' which is in rougher shape than my first 650, so I like your advice. I'm new to working with motorcycle brakes - I had erroneously concluded that my caliper looked like crap on the inside.... Thanks!

Advice on where to buy stainless steel braided brake lines or which brand to go with? I'm favoring a one-piece. Does the triple-tree thing get eliminated?

 

[XSLeo]

There is a fellow on here, shawn00 something. I don't recall exactly. Has a one piece line for sale. On the M/C end it has a banjo connection, on the caliper end it just threads in where the old steel line did.
On the junction on the tree, some years this held the front brake light switch. If yours does, no problem. Just get a banjo bolt switch. replace the banjo bolt in the M/C, wire it up be happy.
Oh here's a pic.
Leo

 

[YL82]

Thanks, Leo. I'llshoot Shawn a PM.

This is a good thread that I should have read earlier...

http://www.xs650.com/forum/showthread.php?t=29264&highlight=Rusted+caliper&page=2

 

[YL82]

The Service Manual refers to the necessity of replacing the "Bridge Bolts" each and every time they are removed whether or not they are damaged.

Which bolts are these? Does anybody replace them each & every time?

Answer to Question #1:

1 x Bridge Bolt 1: 306-25821-01-00 (large bolt)
1 x Bridge Bolt 2: 306-25822-01-00 (double-threaded bolt w/flanged middle)
2 x Bridge Bolt 3: 306-25826-01-00 (two standard socket head screws, takes M6 hex key)

All are obsolete by Yamaha. Bridge bolts 1 and 3 shouldn't be hard to match up, not sure about #2.

I've concluded that my bridge bolts are just fine....

 

[5twins]

I doubt anyone replaces them. My old BMWs call for replacing certain bolts if removed, namely the flywheel and drive shaft coupling bolts. I rarely did. They were apparently made to stretch with use, hence the need for replacement. Maybe the Yamaha bolts are similar? I just thread them in and test fit them. If they go in easy by hand, I pronounce them "un-stretched" and re-use them. If they screw in hard, like they're cross-threading, I do replace them. Those would be stretched.

 

[TwoJugs]

Probably more a liabilty issue. When it comes to brakes they like to replace alot, not reuse or repair.