New Front Brake Master - Compatibility

I have a pile of gen2 klr parts and the front master looks identical to one of the old kz650 ones I have my bike is a 79 650 d2 (SR) and I bought a cheap chinese set off of flea bay but just cant get it to bleed, the rubber keeps collapsing and it seems to suck air at the master, its garbage. Any chance the klr one fits? its sure seems to. Any other OEM ones fit that arent 8 million bucks? or anyone have a used working one they want to sell? I have three seized ones here, two round, one rectangle.

thanks!

With the new one, do you have a brake bleeding apparatus set up & are you keeping the reservoir filled while bleeding the brake?

As for the KLR, is it for a single disk brake or dual disk? Since the SR is a dual disk, you need to use a dual disk mc. 16mm piston bore. some have 5/8 cast or stamped on the underside. 5/8" = 16mm.

You could get a used oem Fr br master cylinder on EB, but it needs to be from a dual disk motorcycle. It wouldn't have to be from a Kawasaki. some of the criteria: 7/8" handlebars. mount angle. dual disk. mirror orifice.

martin

yes of course full res. i have tried vacuum bleeding, pushing the calipers in method(messy) and I have done many bikes and cars before(should have said that) , I have a TINY bit of lever now, but only from leaving the lever strapped to the bar over night. Yes its a dual disc setup, ill check the bore on the amazon one I have on there now, good call, klr is a single rotor. i do have 7/8 clubmans on it, the angle of the upper banjo works ok, as I also have russel braided lines. the other consideration may be the russel banjos I bought, I am wondering whats the torque for those?

cheers

Okay, it sounds like you know what you're doing. you never know sometimes. :laugh:
Maybe the problem is the mc. Even if you posted exactly which one you got, it's hard to say whether that's the problem or not.
I'd guess just use the banjo bolt torque listed in the manual.

My 81 KZ650-CSR has a single disk Fr br which I refurbished last year & I installed a speed bleeder which made the job easy.
Not sure if this was necessary, but I disconnected the caliper from the fork leg & placed it as high as it would go on top of a tall box with the bleeder facing up, so that the air would have the easiest, quickest path to the bleeder. I connected clear tubing to the bleeder so that I could see the air bubbles. no problems whatsoever.

Sometimes the master cylinder resists "priming" and you need to force it. Basically you need to make fluid enter the pumping chamber one way or another. You can figure out if the master is pumping by cracking the banjo at the master and pulling the lever (use a rag to catch any fluid). If you don't get fluid then I'd remove the master and work over a catch tin and try to force fluid into the master on way or another until it pumps. Vacuum often helps. Then reinstall and go.

BTW, if the master bore is smaller than the original 5/8" then the hand lever will feel spongy when you pull the lever.

first off you guys are awesome, good info. So what I did is bled the master first, on the bench., basically as described. then connected the splitter, and barfed fluid through that as well, then added the calipers, same deal, then mounted the entire setup as a unit. the bike is torn apart so it was simple, but effing messy. so from what you have said, I did some research, the one i bought is 12mm bore, so its too small by what youre saying. If I zap strap the lever to the bar, its gains some 'pedal feel' to it, but pumping it up after seems to lose that, and actually sucks the rubber diaphragm into the master, then it starts leaking. so undersized, and cheap chinese garbage. any suggestions on a replacement? I have a million clutch levers now, grrrr. and thanks

PS, it does now seems to hold the wheel, while its on the stand, but a spongy front brake lever isnt something im willing to gamble on