Too much Rear Brake

My 79 B-4 has a too powerful rear disk brake. It's just not well matched to the bike. When practicing panic stops, it's virtually impossible to avoid skidding the rear tire.

The bike has a 5/8" rear master cylinder already so I can't reduce the hydraulic force by enlarging the diameter of the master cylinder.

I suppose that I could machine the disk but then I'd have to rework the caliper and mount.

Does any one have an idea how I might reduce the power of the rear brake?

TIA

Bill

I havent heard of having to much rear brake. I would guess there is something out of sort with brake system. I really dont feel the Kawasaki brake system is beyond locking up even in perfect conditions. Might just be a fact of life with the engineering of these brake systems if you fully load them in a panic stop they will lock rear tire.


I have had problems with the rear brake draging the rotor and building up heat. When I applied the rear brake it would grab and then want to lock up.

Thin rotor thickness. Causing heat to build up.

Uneven wear of brake pads.

I have also used a very aggressive brake pads that had a lockup problem.


One way I could see hampering the rear brake would be to notch the brake pad or drill holes in pad. By removing 10-20 or 30 % of the pad it would handicap the brakes ability to stop......it would be tough on the rotor if notched.....holes might be better staggered about the pad.

Can't you just adjust the rod? Making the disc thinner isn't going to do a thing, the caliper will just adjust to the new thickness.

What tires are you using? Is it possible the compound is not sticky enough to give good traction? The Dunlops on my old BSA would have the rear wheel skidding if you even looked at the brake pedal. Ed

You need to pull the pads off and check what type you have. Sounds like you have Semi-Sintered (GG) or even Sintered (HH) metallic pads installed. The "GG" or "HH" will be stamped on the backing plate. I run HH pads on the rear of my drag bike because of the slider clutch. I have to overcome the decelerating engine force and the weight of the bike until the slider drops to a low RPM and drops out. I run a "slick" on front and never grab the front brake in the shutdown area to avoid the front end washing out on me. HH pads work great in my case and I can still lock up the rear if I want. I wouldn't want them on the back of my street LTD. If this is your problem, replace with a set of "organic" or factory pads. The rear will still lock up on demand but won't be as touchy. Don't try to modify any brake parts. Hope this helps.

Thanks guys!

I'll pull the pads out and see if they are sintered. If they aren't, I think drilling holes in the pads would work to reduce the power. Thanks 4TheKZ1000.

Ed, How did you know I had a DunFlops fitted. I chose them for traction on the dirt. Perhaps more rubber on the road is what I need.

Bill

I've used several tire brands and models including 3 different flavors of Dunlops on my KZ650. As far as traction is concerned the Dunlops were the worst of all I tried, so your symptoms sounded somewhat familiar. Of course, that's on the street; they may work better off-road. Ed

I don't know if I can explain it right but if I have to stop real hard I would rather push the limits of my back brake before I push the front one to that point.

I had to lean on the back brake to the point of getting side ways last year.

I saw this guy that was planning to pull out in front of me on a rural highway was more concerned with the on coming traffic then anything from my direction and I was ready for it when he pulled out and at the last second he turn his head and saw me sliding side ways towards him and stopped half way into my lane , he gave me just enough room to get off the brakes and pop in between him and the on coming car :woohoo:

If he hadn't I was aiming for his door and would have been slowed down enough to were it would have been OK

I had my wife on the back and a full pack , we were maxed out height wise and I was squeezing the front brake real good too.

After it was over my wife was pretty impressed at how I handled it, I just was able to see a problem and thankfully react in time.

Take the rear pads off and file vertical grooves(up and down)grooves in the pads,this is how I was taught to do it way back when anyway.

KZCSI wrote: My 79 B-4 has a too powerful rear disk brake. It's just not well matched to the bike. When practicing panic stops, it's virtually impossible to avoid skidding the rear tire.

The bike has a 5/8" rear master cylinder already so I can't reduce the hydraulic force by enlarging the diameter of the master cylinder.

I suppose that I could machine the disk but then I'd have to rework the caliper and mount.

Does any one have an idea how I might reduce the power of the rear brake?

TIA

Bill

You would be trying a smaller bore cylinder to give it some more feel/ more travel of the pedal to get the same force on the caliper. Pad materials make a big difference, as taildragger1197 posted.

Have you tried adjusting the pushrod between brake pedal and mc to slow down the action of rear brake?

650ed wrote: What tires are you using? Is it possible the compound is not sticky enough to give good traction? The Dunlops on my old BSA would have the rear wheel skidding if you even looked at the brake pedal. Ed

Pretty sure you're onto something there Ed.