Topic: Show and describe your brake system upgrades for 550/750 K bikes.

[Mingo]

I've got a 78 750K, and hate the stock brakes. I've rebuilt the caliper and MC, but they still feel unsafe. I know I can get dual front disks, and I probably will--though a quick browse seems to suggest that the dual disks are only a slight improvement. Please correct me if my impression is wrong. But what else have you guys done? Are there aftermarket options, front-end swaps, or any other ways to get these old girls to brake like a modern bike?

[Retro Rocket]

Do a forum search mate, plenty of info and ics already on the forum and a couple of guys that can set you up with the correct parts....
 forum member"fishhead is one of the guys, here's a linbk to some of his stuff..

http://www.geocities.ws/fischervintagecycle/Fischheads.html

[Elan]

Just did a gsxr1000 front end. THeres a number of people here that have done it.  THe discs are hayabusa 320mm,and theres 4 pistons per caliper. havent gotten her moving yet but im sure it will be an improvement.  not exactly a weekend job, though.





But with a stock setup, getting new stainless brakelines helps a little, there less expansion.

[Mingo]

Man, Elan, that's beautiful. I know a few have done that, but you've got to machine new triple-trees, and all, yeah? Is that into the 4 figures?

Retro Rocket, that fishhead site looks interesting, but he has a paragraph specifically stating that he can't do anything for stock SOHC K bikes. So it looks like I need to replace the entire front end if it want to stop abruptly.

Let's see more.

[flybox1]

Love my dual front disc setup.  Thinned and drilled rotors from godffery. Stainless lines from slingshot cycles. New OEM stock pistons. Newer 14mm master cylinder.  EBC Kevlar pads.
Noticable improvement over stock setup.

[Elan]

Man, Elan, that's beautiful. I know a few have done that, but you've got to machine new triple-trees, and all, yeah? Is that into the 4 figures?

Retro Rocket, that fishhead site looks interesting, but he has a paragraph specifically stating that he can't do anything for stock SOHC K bikes. So it looks like I need to replace the entire front end if it want to stop abruptly.

Let's see more.

Had to machine a new stem, bearing cover, and some spacers to the wheel. It's a harley wheel.  under 4 figures, but close...

[Retro Rocket]

So it looks like I need to replace the entire front end if it want to stop abruptly.

Not at all mate, there are piles of ways to upgrade your brakes,one  way is to have spacers made for modern style discs and adapters for the calipers, plenty of guys have done them, another way is to do what flybox1 has done.  The search function is your friend,  i won't be wasting my time searching  for you, i am having too much fun finding my own stuff.   

[crazypj]

550 is worthless with single disc but great with dual disc.
As CB750 is a lot heavier it should have come with dual disc.
 You do need a larger master cyl with dual disc, stock one doesn't really move enough fluid
 I used a stock CB650 (European dual disc) can't remember bore size

[scottly]

I've got a 78 750K, and hate the stock brakes. I've rebuilt the caliper and MC, but they still feel unsafe.

One of the things I've noticed about the K7-K8 calipers is the pads have less swept area than the older caliper pads. I wasn't impressed with a single K7 caliper, even with an after-market cast iron rotor, which has more grip than a stock stainless rotor. I'm currently running a twin brake setup with K7-K8 calipers, stainless Yamaha rotors, and a stock K7 14mm MC. This works well for me.

[crazypj]

From what I remember the K7~K8 used same caliper as smaller bikes (350/360/400/etc)

[scottly]

From what I remember the K7~K8 used same caliper as smaller bikes (350/360/400/etc)

I think not; the 750 K7-K8 caliper used a 42.8 mm piston. As far as I know, all the other SOHC4s used a 38 mm piston. The stock 14 mm MC will move enough fluid for either dual 38 or dual 42.8 calipers, in my experience.

[jason41987]

looking at the stock forks for my CB550F, and the front brake... i could easily switch the brake to the left or right side of the bike... ive been wondering if it would be somehow possible to add a rotor to the other side and have a two-brake setup using stock original CB550 parts (as opposed to swapping on a GL1000 front end)

[Mingo]

Flybox1, that looks great. Are they a real  (as opposed to noticeable, but small) improvement over the stock brakes? How would you say they compare to a modern standard or sportbike?

Do I understand correctly, that what you have is a front end with custom rotors, a second, stock caliper, and an aftermarket MC, and an aftermaket brake line--nothing else? You're using the stock forks, the stock head bearings (not a goldwing front end)?

[InTheStreet]

I just threw a cheap Chinese master cylinder with a 12mm piston from feEbay on mine, scuffed the rotor perpendicular to the center to remove glazing, and I am pretty happy with mine, even when I ride two up. 
The downside to the Chinese master cylinder: need to find a banjo bolt that is the correct size (or rig up a sleeve like I did for the longer, factory bolt) and if the lever breaks (mine melted into the pavement when I was parking "InTheStreet"), you have to buy another master cylinder.  But mine was $40 both times, which appears to be the cost of a lever for better brands.

Did a quick search and didn't see the one I bought listed anymore

[Lostboy Steve]

I was wondering about those masters...

[crazypj]

looking at the stock forks for my CB550F, and the front brake... i could easily switch the brake to the left or right side of the bike... ive been wondering if it would be somehow possible to add a rotor to the other side and have a two-brake setup using stock original CB550 parts (as opposed to swapping on a GL1000 front end)

Been done a load of times, need to modify speedo drive, instructions are here somewhere

[RSchaefer]

I always see this reference for the need to upgrade the MC but HondaMan says there is no need too with the dual front brake setup?

[flybox1]

Flybox1, that looks great. Are they a real  (as opposed to noticeable, but small) improvement over the stock brakes? How would you say they compare to a modern standard or sportbike?

Do I understand correctly, that what you have is a front end with custom rotors, a second, stock caliper, and an aftermarket MC, and an aftermaket brake line--nothing else? You're using the stock forks, the stock head bearings (not a goldwing front end)?

I have no 'modern' bike experience to compare it to, but a seatofyerpants test before and after shows great improvement.
the parts listed, plus a modification to the speedo drive plate(or rotor), and shimming (for alignment) of the additional caliper arm are all thats needed.
its all here...http://forums.sohc4.net/index.php?topic=53532.0

[Retro Rocket]

The modern bike comparison won't add up anyway. Most modern bikes with good brakes have far superior forks and frames, you put gsxr1000 brakes on your 40 year old bike and expect it to brake like a gixxer and you would be wrong, fork and frame flex should be taken into account, in saying that, the modern upgrades are better than stock, just don't all of a sudden expect your old bike to be a modern one....   {yes, i've had plenty of both}

[70CB750]

I run dual disc on the K0 with original master cylinder and it works great. The original MC is sufficient.

For the OP - swap the fork for late F Super Sport - like 78 - and you will be able install modern calipers (2 piston) on original brackets. Somewhere here is a writeup with part numbers.

[Whaleman]

I also use my stock master cylinder with a dual disk setup and if they are bled properly it works great. My bike spends winter in the family room. Dan

[scottly]

Dual K7 calipers with reversed K7 forks, stock 14 mm MC, and Yamaha rotors. (I used the Yamaha rotors as they are lighter than Honda 750 rotors, not for any braking improvement.) The dual brake system performs twice as well as the single, for obvious reasons.

[sethdhawkins]

Early style fork lowers with C-Type bracket, thinned and drilled rotors by Godfrey, EBC pads, new pistons, stainless lines and alloy brake tubes, new Mike's XS tracker style master. Noticeable improvement over stock, but still not safe with the go fast mods that I have. The early style caliper bracket is a pita to work with, relative to the T-type. I'm still looking for options.

[Lostboy Steve]

The modern bike comparison won't add up anyway. Most modern bikes with good brakes have far superior forks and frames, you put gsxr1000 brakes on your 40 year old bike and expect it to brake like a gixxer and you would be wrong, fork and frame flex should be taken into account, in saying that, the modern upgrades are better than stock, just don't all of a sudden expect your old bike to be a modern one....   {yes, i've had plenty of both}

This is probably the best advice I've seen yet. You're 100% right. I would hate to my brakes to work THAT well on my front end. Even will expensive springs and rebuilt forks, my nose loves to dive on a hard stop. I'd still rather a good 50/50 braking effort with the drum doing equal work as the front.

[DJ_AX]

I've upgraded only by adding SS lines and drilling the rotor.
Doing just that has been a very noticeable improvement imho.

I'm sure... not as much as with dual discs ... but still a significant improvement.