Topic: 1978 CB750K Front Brake Rebuild

[Rosinante]

I rode the heck out of a '75 back in about '77-'80 and I was very impressed with its braking.  The front brake worked notably better than the rear, and with both brakes at once that '75 would stop NOW.  In my memory.

Report:  I rebuilt this caliper and MC because I was not happy with braking, and I also installed new shoes in back.    I am still NOT impressed with the braking on this '78.  On this current bike the front brake is not better than the rear.  Is this normal?  It's a little better than before and I will do some more brake bleeding to see if I can squeeze a little more performance out but I may be looking for a better solution.  Suggestions?  Dual disks?  Can I grind the front disk for additional friction?

I gotta say....I am very grateful for the advice.  Thank you!  FWIW, I think the little plugged passage in the MC was likely the reason for brake dragging.  More so than the seal-flex thing.  I could give a long explanation but the short version is that I think hydraulic pressure against the pad/disk interface is needed for brake dragging.  I don't think pistons move when braking. 

[newday777]

If you still have the rubber hoses get some stainless steel brake hoses for full pressure to the pads.
Yes you can thin the rotor, and drill them too for better stopping. Godffery's Garage (Jeff is a member here) does them correctly. Less weight and better stopping.

http://forums.sohc4.net/index.php?action=profile;u=7132

[Rosinante]

I believe you.

Keep it coming.  I am waiting to hear about a MC cylinder with smaller bore.  Everybody talks about big bore MCs and those would actually provide less braking.  Smaller bore would provide more braking power, but also more travel.  Which SS lines could address.

[calj737]

The front brake worked notably better than the rear, and with both brakes at once that '75 would stop NOW.  In my memory.

The front brake on any motorcycle always provides more stopping power than the rear. Under aggressive braking, weight is transferred to the front, unloading the rear. There is a substantial increase in friction of the front tire during this moment. The rear brake is nearly useless during aggressive braking as the suspension has already rebounded to react to the front loading.

Adding rear brake near the end of the braking event can help improve stopping distance, but should not be activated during the initial event. And absent of a blown front tire, gravel, dodgy surface, the rear brake is not recommended as a primary source for stopping. There are ample uses for the rear brake but poor technique uses of it contribute to more crashes than avoidances.

[Rosinante]

Thank you.  Front brake performance on this bike sucks.  It does not have more stopping power than the rear.  Or at least, if it performs better than the rear, the difference is difficult to perceive.  I started a new thread for this specific topic/question and asking for tips and solution alternatives.