1. Dismiss Notice
  2. Dismiss Notice
  3. Hey Facebook people... We've created a group for XS650.com members to connect. Check it out!
    Dismiss Notice

Brake Overhaul/Upgrade Questions

Discussion in 'The Garage' started by XSRocket, Mar 12, 2019.

  1. XSRocket

    XSRocket XS650 Member

    Hi all! I finally got my '82 back into service after a top-end rebuild. I was never happy with the braking, so I took a look at the caliper and it seems like I'm in for an overhaul of the front brake system.

    There are good guides on this forum for rebuilds of the caliper and MC but I'm debating a few upgrades while I'm at it. I was hoping to get some advice on those fronts.

    I don't have a whole lot of experience with other bikes and I've never known what good stock braking feels like on this one, so that's kind of where I'm coming at this from. Are any significant upgrades worth jumping into from the get-go?

    I think a new one is worth the $ to me here. The piston boot on the current one was just ...not there? The piston is all gunked up and corroded from what I can see, and I can't get it out of the caliper with compressed air. I don't think it was sliding correctly either.

    Do I just go with a replacement from Mike's? Go for the upgrade to a brembo caliper with the phantom kit? See if I can salvage the old one after all?

    Pads and rotor:
    The pads seem to be in good shape, lots of life left. The rotor looks stock (not drilled) and looks ok, though I don't have the tools to measure properly.

    Does anyone have experience with the rotor upgrades from 650central? Do I need to bother yet?

    Replacing. Are the braided steel from Mike's any good?
    Do I need to do anything other than clean that L-shaped joint?

    I should probably take it apart before I decide whether to rebuild or replace, I guess. Mine looks like the oem-type 13mm one on Mike's.

    Is an upgrade (say to a brembo from 650central) worth doing?

  2. motormike

    motormike XS650 Addict Top Contributor

    B/steel line worth the cost.... as for the piston.... use a socket..vise..press-bottom piston....then clean the gunk...it must be clean..clean.... with a dental pick... I have been able to pull the piston seal.. square O ring out.....it will come out in pieces....then leave caliper in vise.. place a rag between the piston and vise face... give the caliper a shot of air... sometimes it pop's out with great force.. that rag helps catch the piston and prevents possible damages. Other times.. the piston will move a little.. grab the socket..bottom the piston... replace rag... place in vice... repeat...Only once I had a piston the wouldn't come out....
    With piston out... inspect the surface.. and caliper bore.... most of the time.... serviceable.... clean clean..clean again.... use a 90 degree pick and clean clean, and clean the square O ring channel.... I clean it until the piston can fall out of the bore on it's own..without the O ring. Use a small mirror and bright light...O channel; clean ? Insert new ring...press in it..I use the side of a heavy socket and press with some force. Then with a clean finger.. coat the bore with brake fluid…. then press in piston.... recall all that gunk and corrosion.... mostly condensation... even with a good dust boot... I apply a small amount of brake grease then toss on new boot cover. This grease helps prevents condensation.
    Pads..... coat the back with brake grease.... helps prevent chatter.... sometimes the pads are heavily painted from the factory… this will cause them to drag.. remove the paint until they slide freely in the caliper pad bracket Caliper rubber.jpg On the caliper mount'n bolt.. usually the slide doesn't..slide….the rubber boot.... always needs replacement... recall the miss'n caliper boot... usually leak'n forks....fork oil and caliper rubber parts.. don't agree... the rubber will swell.... after you replace the caliper boot.... stuff it full of brake grease.. then insert the sleeve.. again.. this displaces condensation….
    as for rotors.... I tape off the painted parts..then media blast it.... back in the day... brake jobs " turned" the rotor.. besides true'n it...it also clean'd the surface of residue from the old pads...
  3. 5twins

    5twins XS650 Guru Top Contributor

    Yes, you'll need to "work" the piston out. Squeeze it in with a big C-clamp, blow it out as far as it'll go, squeeze back in, blow out, etc. Eventually it will come out.

    Yes, you will need a replacement brake line. The original rubber ones are all shot by now. Yes, go braided stainless, they're dirt cheap now. I just picked up a couple of these for the Princely sum of $4.74 each .....


    With a new line and cleaned out stock components, I don't think the stock system is too bad. The only additional thing I did to my '78 was drill the disc, and I was quite satisfied with that set-up for many years. I eventually replaced the pads with supposedly better aftermarket ones, but I wasn't impressed. They were really no better, if any better, than the original stock ones. I have acquired another 650 now and did the same to it's stock front brake except for the disc drilling. It doesn't seem to stop as well so I guess the disc drilling does help. On my '78, I never drove it without a drilled disc.
    Last edited: Mar 12, 2019
    OHRider likes this.
  4. XSRocket

    XSRocket XS650 Member

    Thanks for the advice, gents. I'll see if I can work that piston out and go from there!
  5. I don't have the tools to drill the disc, so on my '82 I fitted a replacement EBC rotor as well as the caliper rebuild, new EBC sintered pads, and braided stainless line. What REALLY made a difference though, after all that, was changing to an 11mm m/c. Mine came from a Triumph Adventurer, via the usual eBay route.

    I now have an excellent front brake I can trust.
    gggGary likes this.
  6. stinky78

    stinky78 XS650 Member

    I bought the Mikes stainless 41” line, I had read here that others had used it and it was good, the one I got just seemed cheap and nasty, the banjo fitting made of aluminium and are screw on so wouldn’t be dot, also the hose just looks cheap, also it is too long for my 77 with stock bars, might be OK for a special, but I can’t imagine it would need to be 4” longer, link to the one I bought below.

  7. fredintoon

    fredintoon Fred Hill, S'toon. Top Contributor

    Hi Rocket,
    first, the stock m/c's piston area is twice what it should be to work a single caliper. (m/c works OK for the two calipers the Euro & Aus XS650s got)
    Either add the left-side caliper & disk or use a smaller piston diameter (11mm, 12mm or 1/2") m/c.
    Second, the stock brake hoses are fabric so they bulge like grandpa's arteries on his 2nd honeymoon and are WAY past their "best before" date.
    Replace with either two s/st brake hoses or just use a long single s/st hose.
    Drill the bejasus out of the brake disk. (lotsa ~5/16 dia holes in ANY symmetrical pattern.)
    Once you get the bastard bled that upgrade will easily squeal the front tire on a dry road.
    ThatXS650Guy likes this.
  8. 5twins

    5twins XS650 Guru Top Contributor

    Technically, the size of the holes you drill in your disc should be kept at or below however thick the disc is so you don't lose surface area. The stock 650 disc is 7mm thick so about 1/4" is the biggest you would go on the holes. Personally, I use 3/16" holes. Besides being easier to drill than bigger holes, this size will also work OK on 5mm thick discs.
  9. fredintoon

    fredintoon Fred Hill, S'toon. Top Contributor

    Hi 5twins,
    to avoid loss of surface area what you lose (twice the hole area) must equal NOT the disk thickness but the hole's cylindrical area.
    as I remember the calculation the "no loss of area" hole diameter for a 7mm thick disk is about 0.4"
    I used 3/8" so I was still ahead on cooling area but Lord did the holes take mega-efforts to cut even with flood cooling, 3/16' pre-drill and cobalt steel bits.
    Note that the smaller the hole the more of 'em you gotta make and that the pads don't care what the pattern is so long as it's balanced.
  10. 5twins

    5twins XS650 Guru Top Contributor

    I'll admit, it was just something I read on the internet somewhere, so it must be true, right? lol.
  11. Machine

    Machine Race the wind Top Contributor

    Just a question about disc drilling going in right here.
    Aren't drilled discs infact just better in wet conditions ?
    Im having trouble understanding how the holes can benefit braking on dry days other than possibly heat disipation ?
    Thanks, -R
  12. 650Skull

    650Skull Dinosaur Lives Top Contributor

    I think part of the reason to do this is it sweeps the pads to help stop contamination build up...........This only works if the holes have their sharp edge intact.........also to help cool the rotor's under heavy use, and lets any air trapped under a pad to be dispersed into the holes supposedly making a better contact
  13. mrtwowheel

    mrtwowheel Honda Etched On Brain Top Contributor

    I was checking out a Harley at the diner one morning. I was interested in the factory drilled rotors because I was planning to drill my front XS rotor soon. First off, I noticed that the holes were much larger than I was planning to do, larger than 1/2". Second, I could not, no matter how hard I tried, see any pattern, whatsoever, to the holes that were drilled. The owner of the bike came out and seen me looking like I'm thinking about taking parts off of his bike. I say, "there's no pattern to those holes drilled in your rotor". He says,"there's a pattern there if you look hard enough". I said,"I can't look any harder".

  14. An alternative to drilling your stock brake rotor is to replace it with a slotted righthand rotor from '80-'81 XS1100 or '82 XJ1100, p/n 3H5-25831-10-00. This is a plug-and-play swap if you can find one. It's thinner than the stock 650 rotor, so you save some unsprung weight as well as all that hole drilling. 21 inch rim and tire.JPG
    Machine likes this.
  15. fredintoon

    fredintoon Fred Hill, S'toon. Top Contributor

    Hi aldo,
    an XS11 slotted rotor will save a whole bunch of heavy duty drill-press work, the trick is finding one. Even Andreas Weiss don't have any.
    I got 3 but they are on my XS11SG. Yours for a $1,000 with free bike.
    Or if you have a "bro with milling machine" you could have him slot an XS650 disk for you.
    Last edited: Mar 15, 2019
    aldo5468 likes this.
  16. fredintoon

    fredintoon Fred Hill, S'toon. Top Contributor

    it's OK, the pads can't see a pattern either, even if there is one.
    You could even spell out naughty words or political statements and the brakes would still work.
    mrtwowheel likes this.
  17. 5twins

    5twins XS650 Guru Top Contributor

    It will be interesting to see what difference adding a drilled disc to my '83 makes. Like I said, I never drove the '78 without one. The '83 brake functions fine, no leaks and a nice firm lever, it just doesn't stop as well as the '78.
  18. Brassneck

    Brassneck XS650 Guru

  19. I was lucky, I guess - found the one shown in the pic several years ago on eBay, which shows it on a 21" rim I had at the time. I did change back to a 19" rim, laced to the same hub with the XS1100 rotor. Single stainless steel line, 1/2" bore XV250 m/c, Brembo 4-pot caliper - I think if I launched at the right "uphill" angle, I could put myself in low earth orbit, but I'm too old for that stuff now.
  20. XSLeo

    XSLeo XS650 Guru Top Contributor

    On the XS1100 rotors. They made two versions of the bikes. The Standard and a Special.
    The standard used the same style of forks our XS650's use. The Axle was right on the bottom. The Special's used a different fork. The axle was on the front of the fork lower and up a few inches from the bottom. These are leading axle forks. They used a different caliper and rotor size.
    The Same applies to the XS850 and XS750. I bought two sets of the slotted rotors. One set was from an XS1100. These were 7 mm thick. The other set was from some other bike. They were 5 mm thick. The 5 mm are on the 75. The 7 mm are on the 82.
    There is about a 28% weight savings on going to the 5 mm rotors.
    I learned these differences in the brakes the hard way. Bought the wrong parts because I didn't know better. I might recommend asking the seller to give you the rotor diameter before you buy.

Share This Page