Can't Lock Front Brakes

[WaddleDee72]

Hi everyone,

I recently got a newer sport bike, and it made me realize how truly awful my front brake is on my '78 CB750F. Only squeezing with my index and middle finger, I can barely build any brake pressure. Using all four fingers, I can stop, but I can't lock the front brake. And since I can do a legless rope climb, I don't think grip strength is my problem.

I had my Honda mechanic rebuild the front master cylinder and replace the front lines with braided lines, but I was disappointed to find that it made no difference. Do other people's brakes also feel this weak? Or could my problem lie in the calipers or pads?

 

[brettp]

Hi everyone,

I recently got a newer sport bike, and it made me realize how truly awful my front brake is on my '78 CB750F. Only squeezing with my index and middle finger, I can barely build any brake pressure. Using all four fingers, I can stop, but I can't lock the front brake. And since I can do a legless rope climb, I don't think grip strength is my problem.

I had my Honda mechanic rebuild the front master cylinder and replace the front lines with braided lines, but I was disappointed to find that it made no difference. Do other people's brakes also feel this weak? Or could my problem lie in the calipers or pads?

I think this is pretty common, I've read about it here on this forum. Some people upgrade to a dual disc then upgrade the master cylinder to handle the increased volume of brake fluid. You need to search the forum if you want more info, In don't remember the specifics.

 

[WaddleDee72]

I think this is pretty common, I've read about it here on this forum. Some people upgrade to a dual disc then upgrade the master cylinder to handle the increased volume of brake fluid. You need to search the forum if you want more info, In don't remember the specifics.

I have the CB750F (Supersport), which came with dual rotors/calipers from the factory. I’d like to not replace the master cylinder, because that will take away from the ‘70s looks of the bike, but if that’s the answer, that’s the answer I guess.

 

[brettp]

If you already have dual disc's, I would suggest changing the fluid. Could be that simple.

 

[dirtdigger]

Dont know what your modern sport bike you are comparing it too but the old 750 definitely will not brake as well as a modern sport bike. 40 year old brake technology wont compete with modern stuff, just look at the size difference or the rotors. The old 750 is gonna be about 100 lbs heavier then most new sport bikes also....thats a huge amount. I personally wouldnt want to be able to lock up the front wheel on one of these old bikes, with how soft and small the front forks are and the handling of the old chassis I would be some what afraid of that much stopping power. You could probably look into seeing if there is a more modern brake pad material and see if it helps, maybe rebleed the system to make sure all the air is out of it.

 

[kirky]

my 79 750 Fz has had pistons and pads etc and after about 1000 miles i thought it would be better than it is, but as dirttdigger says 40 year old and good enough for me, and certainly 1000% better than my73 year old BSA