DIY brake upgrade for sohc Honda CB750F
By mixing and matching OEM parts you can increase the braking performance of your latter CB750F Honda
Part of the theme here at Mechanical Advantage is to take the time to figure out simple modifications to vintage vehicles that will improve the performance. Often we are also thinking about how to do this on a budget. In today's "tech tip" I wanted to talk about a simple bolt on brake upgrade that uses all OEM parts. While myself and Kerry will be sharing our tips, our hope is that others will follow suit and educate us on interesting upgrades.
This trick will work on any 1977 or 1978 Cb750F SuperSport. I have been told that it also works on a few other bikes that use similar forks.
The upgrade boils down to the fact that the twin piston calipers from a 1982 (and other years) CB900F will bolt onto the 750 forks. Not only do you end up with better looking calipers, but you get twin pistons that perform better and a wider range of pad options.
The OEM part numbers that you need. They can be cross referenced to a few different bikes to help with the eBay searching.
137905-001 left bracket
137515-001 right bracket
139361-001 left caliper
137472-001 right caliper
SOHC Vs DOHC
Installation is very simple. Basically you swap the brackets and calipers.
Bracket bolts to the fork legs.
There is no need to cut, grind or shim anything as the spacing for the rotor is perfect.
Rotor is centered.
Now the caliper mounts to the DOHC bracket.
Simple as pie
Lines route the same as stock.
While everything is apart it might be a good time to think about replacing the seals, pistons or upgrading the lines. I LOVE slingshot cycles for braided lines. Great product at great prices. For pads I have had good luck with EBC FA69 in their HH rated compound. Each time I have done this swap I have changed all the boots and seals using OEM parts from Honda. Prices for all the service stuff seems to be cheaper for these then the original single piston calipers being replaced.
Few variations if you are thinking a little “outside the box”
First there are some of these calipers that are 30mm like the 1982 CB900F and some that are 32mm. The size is normally cast into the side of the caliper. I actually run V65 calipers on my bikes. The V65 calipers will bolt right onto the 900F brackets. I started using them not for the 32mm pistons, but because the calipers are generally cheaper. I guess more people want CBF parts then V45/65 parts.
Honda used many different castings of the same basic caliper. Casting that I have seen say “Honda”, are blank, have an “X” or other words. So far most have worked for this swap. I tend to be uber cheap so if I come across cheap calipers I think will work I grab them to use latter. There is a “decoding Honda part numbers” PDF floating around the internet. It might help a novice figure out what else might work.
Different casting if you perfer
Bike used in these pictures is my personal, and never ending, CB750 CR build. The wheels are Lester, but are direct replacements for the stock ComStar wheels. Also the rotors are drilled.
If anyone has any questions or needs help with the swap please feel free to reach out. Will post a similar DIY upgrade for the rear as well as some info on rebuilding the calipers.
At some point I feel I should work on upgrading my photography skills too.