Prolink front mc options

[Larry Zimmer]

Sounds good. Where did you find the ss pistons?

[cross]

You probably have the typically crud buildup between the caliper and the square shaped seal which will prevent the piston from retracting. Caliper rebuilding is the required fix. I've never seen that seal "turn over" but, I've seen hundreds of calipers (and master cylinders) with this condition.

If you install one of those 19mm Brembo's, you'll experience a vast improvement.

Brake bleeding tip - Upon reassembly of the caliper, wrap the bleed screw threads with teflon ribbon, 2 to 3 wraps. Then with the m/c full of fresh fluid, suck the fluid through each caliper with a hand pump vacuum to get the majority of the air out of the system. Then pump/pressure bleed as usual to get a hard lever.

And this would be the one for '08-'22 Kawa Concourse?
Does the Prolink brake cable banjo and bolt size match kawas?

Thank you
Sasha

Yes, for size and thread pitch but, you may need a slightly longer line from the stock length.

Perfect, thank you sir

Sasha

[Warwick Biggs]

Larry, the stainless caliper pistons are available from WeMoto. I believe they source them from David Silver.

[Larry Zimmer]

Thanks, Warwick.

[Warwick Biggs]

OK, I installed the 16 mm Brembo mc after installing new pistons and seals in the calipers. The dragging caliper was caused by both the dust seals on the left side that had disintegrated and strips of which were jamming under the pistons. Why one side only is a mystery because the pistons on both sides were already stainless and were unmarked but I put new shiny ones in anyway.

The Brembo radial mc helpfully had a bleed nipple on it so I did not have to use plumbers tape or have any trouble priming it. I then spent 15-20 minutes using a hand operated vacuum pump to get most of the air out of the lower lines and calipers. The biggest issue in doing that is holding the plastic tube over the bleed nipple and preventing air leaking in between the tube and the nipple. Ideally, an assistant is needed. When you open the nipple you can easily dislodge the tube and so it can be a very messy job too. I have yet to find a tube or fitting that tightly grasps the nipple and doesn't leak air. I had a very old one that was only about 6" long that I used for years but it disappeared after a track day. The nipple caps that came with my vacuum pump are all too big for motorcycle nipples. Any suggestions anyone?

I have yet to test the new mc at the track but just wheeling the Lump around in the workshop it feels noticeably better than the old David Silver mc that always felt a bit dead. Incidentally, that mc that is sold as a replacement for the OEM item did have a tiny return hole next to the main hole. However, it was obscured by a tab that had been bent back from the main hole, presumably to stop crud settling in the hole and blocking it. I tested it with a 0.5 mm piece of stainless lock wire that went thru' easily. So the dragging brake was not caused by a blocked return hole.

I hope this thread assists those CBX owners looking for a cheap method for improving Prolink brakes. In short, good pads for the intended use (I use HH sintered for racing), braided lines, a radial 16mm Brembo mc off a Ducati and bleeding thoroughly with a hand operated vacuum pump.

I also use Honda VTR full floating rotors that weigh a fraction of the ventilated originals as well as a 17" VTR front wheel that is similarly much lighter than either Comstars or Boomerangs. A piece of 6mm think alloy plate cut to the same pattern as the pads and placed behind them acts as a spacer. This dramatically reduces un-sprung weight and improves steering response altho' I do not encourage any owners thinking of going beyond 18" wheels if they value ground clearance and their safety. Doing so safely requires tricky chassis mods that are beyond most DIY'ers.

I should also add that I used compressed air and a piece of specially cut wood placed between the pistons and the back of the caliper to get the pistons out and then brake cleaner and compressed air to clean the passages of the caliper.

[daves79x]

The tab over the bleed hole is to prevent the return 'splash' from the hole when you have the cap off. Otherwise brake fluid will splash out when operating the lever. Only some m/c have this, the design of many others doesn't allow the splash in the first place.

Dave

[Warwick Biggs]

Thanks Dave, I replaced the tab back into it's original position after it pulled out. It is just a press fit into the main hole and it popped out when I tried to bend it back to access the return hole. I wondered whether it was really necessary at all. I will keep the mc in my spares box for next time I fall off on that side. Levers and clip ons are always vulnerable even tho' I now use lever guards and the rhs is the more expensive side to break..

[MtnMann]

I have yet to find a tube or fitting that tightly grasps the nipple and doesn't leak air. I had a very old one that was only about 6" long that I used for years but it disappeared after a track day. The nipple caps that came with my vacuum pump are all too big for motorcycle nipples. Any suggestions anyone?

The clear vent tube that came with my new lead/acid battery fits very well for bleeding. I used to use various sizes of surgical tubing but they decided to find new homes…

The Teflon tape on threads of the bleeder screw is to prevent air from being sucked past the loosened threads. Although not necessary (especially on pressure bleeding), it does make it very obvious when the air is gone from inside the system.

Fun fact: on airplanes, braking systems are filled by pressure from the bottom up. Very efficient with no fluid waste. Of course that’s after disassembling and cleaning calipers completely so no contaminates are forced back up to m/c.

[Warwick Biggs]

Yes, that makes sense and I have used a syringe to refill from the caliper back up to the reservoir but unfortunately it does not necessarily get rid of all the air, at least not on the rear Prolink mc. The vacuum technique is probably the best IMO but holding the tube on while pumping can still be tricky. Some sort of tiny hose clip might work.

[daves79x]

You are correct, filling the CBX brake system from the bottom does NOT remove all the air.

Dave

[hondaman160mph]

Yes, that makes sense and I have used a syringe to refill from the caliper back up to the reservoir but unfortunately it does not necessarily get rid of all the air, at least not on the rear Prolink mc. The vacuum technique is probably the best IMO but holding the tube on while pumping can still be tricky. Some sort of tiny hose clip might work.

I use a very small nylon zip tie around the tubing in the groove
of the bleeder nipple cinched up to prevent air leaking.

[Warwick Biggs]

Thanks, I'll give that a try.