Topic: CB650 brake caliper swap

[socal1200r]

Does anyone know if there is a two or four piston caliper that is a direct replacement for the single piston caliper on a 1979 CB650 standard?  Finally got my bike on the road after having it in the shop for almost a month, and I'm not impressed with the stock brake setup.  I got another stock front rotor off eBay that I got cross-drilled, and installed new EBC FA45 pads, and even with a new s/s front brake line, I'm still not impressed.  I'm thinking a two-piston or even a four-piston caliper would do wonders for that single rotor front end. 

[buffalogt750]

Goldfren 068AD brake pads are a sintered pad and I think a HH compound. They should give you more stopping power than the EBC's you have. The holes in a drilled rotor should be alternating so they overlap each other and contact the whole brake pad. Your rotor could use a series of 3 holes in between the 2 holes to achieve this. A drilled rotor also may not improve your braking power but it keeps the pads cleaner and may improve wet braking. A smaller bore master cylinder like a 13mm would also give you more stopping power. You can adapt a two piston caliper to your forks but a four piston may not fit between the wheel and caliper. I used a master cylinder and two piston caliper from a late model Kawasaki KLR650 on my 1976 CB550 after giving up on the anemic stock brake setup. Lots of work adapting the caliper but your fork caliper mounts should make adapting a caliper an easier job than mine was.

[cb650]

The 82's had 2 piston calipers.  the disks and calipers will bolt on.  But that is only a few years newer than yours.

[fizzlebottom]

The 82's had 2 piston calipers.  the disks and calipers will bolt on.  But that is only a few years newer than yours.

Be careful doing this though. If you do happen to find a front brake setup off an '82 650, check the pistons for pitting before buying. Originals and aftermarkets are not manufactured anywhere anymore, so eBay or a machine shop are the only places you'll likely find replacements. I had to have a machine shop make me new ones.

[socal1200r]

Thanks for the replies, appreciate it.  'Course another option is to not ride the bike beyond its current braking abilities, which I might just do.  No sense in flogging a 35-year old bike like a modern sportbike, so maybe I'll just accept it for what it is and enjoy it, lol! 

Understood on the rotor, the shop that did the work actually did it wrong.  I wanted two rows of 12 holes each, but wanted the bottom row staggered from the top row, so they weren't right on top of each other, but rather alternated.  Oh well, understanding plain English might be a lost art in some businesses.

Since I drilled the rotor, got new pads (I wanted organic pads, not sintered ones), and have an s/s brake line, that leaves the master cylinder and caliper as the only variables.  I might replace the master cylinder with a newer one, to see if that improves the brake feel to where I'm happy with it.  But again, it is after all a 35-year old bike, so as long as I keep that in mind, I may just start enjoying it as it is.  It's got nothing on my Cagiva as far as brakes go though, but then I wouldn't expect it would, being a single disc front / drum rear versus triple discs on the Cagiva (with s/s lines on each caliper to boot).     

[MiGhost]

The 82's had 2 piston calipers.  the disks and calipers will bolt on.  But that is only a few years newer than yours.

The forks were changed to a lead axle on the 81 Custom/82 Nighthawk. Which increased the rotor diameter to 276mm from the original 240mm, and will not work with the early single disc forks. If you go this route. Make sure the rotor is from the single disc brake models.

[cb650]

Yes I was assuming he would figure a standard as he has a single disk.  Also the 82 nitehawk is even bigger forks than the 81 custom.  And the nitehawk got more rake int the head which accounts also for the wheelbase change.

[socal1200r]

The 82's had 2 piston calipers.  the disks and calipers will bolt on.  But that is only a few years newer than yours.

The forks were changed to a lead axle on the 81 Custom/82 Nighthawk. Which increased the rotor diameter to 276mm from the original 240mm, and will not work with the early single disc forks. If you go this route. Make sure the rotor is from the single disc brake models.

I sent an email to Cyclebrakes.com, and one of their techs sent me a reply, and wanted me to call him.  He wanted me to take a bunch of pics of the stock caliper, and get a measurement for the mounting bolts.  I also told him I'd measure the stock rotor and send that to him as well.  The reason why I mention this is I measured the stock rotor, which I took off and replaced with a drilled one, and it measured at 275mm, plus or minus a mm or two.  It's definitely NOT 240mm, which it should be for a single disc 1979 CB650?  This tech guy has some ideas rolling around in his brain, so we'll see what he comes up with.  He cross-referenced the EBC FA45 pads I installed, and found some 2-piston rear calipers that used the same pad.  But with the odd 65mm mounting hole measurement, I'm not holding my breath that he'll find something that will be a direct bolt-on replacement. 

[trueblue]

CB400N calipers are twin piston and are a direct bolt on to the 650's.  When I did my 650 I looked into using them, but I prefered the look of a single piston caliper on it.  My bike being a 650Z has twin rotors from factory, it has plenty of stopping power.  I ended up using CX500 calipers, they too are a direct bolt on replacement, but look much nicer than the 650 calipers.