Caliper upgrade - Questions.

Hi everyone,

I have just finished fitting a set of SV1000 calipers to my K3 SV Trackbike, fitment was good and seem to sit pretty well over the rotors.

But, the lever seems to take a bit of pumping before i get a good resistance, I can't seem to get any more air out of the calipers, and i've bled calipers before. Could it be that the bore or stroke length of the master cylinder is different? I'm going to leave a cable tie on overnight to see if that will help...

Maybe I could do with a larger bore to accomodate the extra four pistons?

Once resistance has built up the lever is about 3/4" away from the throttle tube. It just takes two or three pumps to get there...

Any ideas from anyone would be greatly appreciated.

Thanks in advance.

[Dave20046]

Try cable tieing the brake lever back to the bar over night then open and close the bleed nipple (fast) Any improvement?

[yorkie_chris]

This does not sound like air in the lines. Air does not make its way downhill if you leave it for a bit...

Maybe dust seals are binding and pulling pistons back into calipers.

[Bibio]

mines the same with the 6 pots.. the sv M/C is the culprate i think... they are more than adequate while driving though... and stop the bike rather sharpish...

I'm not sure what spec/design calipers are on the 1000, but guess they're opposing piston calipers?

If they're a higher spec of any kind, will they not need more fluid to function? Either way, I'd have thought an SV1000 lever and master cylinder would be needed to properly operate the calipers.

sv1000 calipers are 4pot arent they? will need the master cylinder aswell as the calipers to get any good out of them

[yorkie_chris]

Originally Posted by ryangarside

sv1000 calipers are 4pot arent they? will need the master cylinder aswell as the calipers to get any good out of them

Yes change the master cylinder or you'll die. Horribly. Fiery inferno... et cetera...


Have a look, closely compare the 650 and 1000 master cylinder. See what major difference there is to get any good out of them? No? Same part!!

Fiery inferno optional


The pistons on a sliding caliper move twice as far, ish. So the same piston area master cylinder still works fine. That 5/8" master cylinder seen on all SV650 and 1000 is also used on loads of GSXRs with 4 and 6 piston calipers.

Originally Posted by ryangarside

sv1000 calipers are 4pot arent they? will need the master cylinder aswell as the calipers to get any good out of them

the sv650 and 1000 use the same master cylinder.they are both the same part number

[Sid Squid]

Do you have to pump up the brakes each time you use them?

If yes, then the caliper/s is/are sticking and dragging at least one piston back when you release the brake lever, requiring the pump up I think you're meaning when you use the brake.

[garynortheast]

This is such a common story. The culprit is usually as YC has suggested, a binding dust seal. It happens because corrosion in the dust seal reccess forces the seal out far enough to grab the piston and pull it back into the caliper when the lever is released rather than allowing it to move through the seals in order to compensate for pad wear.

Split the calipers, remove the seals and clean every last bit of the white oxidisation out of the recesses. Seals back in with a good smear of red rubber grease and after bleeding you should have good brakes.