Topic: Front Disc Performance Improvements - Bad Brakes

[Garage_guy_chris]

I have had similar problems with my brakes I have a CB450 that uses the same brake setup as the 750 with 38mm caliper, drilled disc, CBR600F3 master and 2 different sets of pads EBC and NOS Vesrah and it doesn't stop worth a damn.

What is the size of the CBR600F3 master?

The CBR600F3 master is 1/2" or 12.7mm

i have 3 Honda master cylinders i play with when setting up brakes. all three use the same levers and are the same sizes externally

CBR600F4i  5/8" -  15.9 mm
VFR800               -  14.0 mm   
CBR600F3           -  12.7 mm

[scottly]

If you want to really improve the front brakes, add a second disc. I've had twin iron rotors with 38mm calipers and sintered pads, a single iron rotor with a stock K7 caliper and pads, and am currently using twin thin stainless rotors with K7 calipers and pads, all with a stock 14mm master. The original twin iron rotor setup was downright grippy, the single iron rotor setup left me wanting more brake, and the current setup is just right.

[HondaMan]

If you want to really improve the front brakes, add a second disc. I've had twin iron rotors with 38mm calipers and sintered pads, a single iron rotor with a stock K7 caliper and pads, and am currently using twin thin stainless rotors with K7 calipers and pads, all with a stock 14mm master. The original twin iron rotor setup was downright grippy, the single iron rotor setup left me wanting more brake, and the current setup is just right.

That's been my experience, too, Scottly! My 2-disc setup (about to get re-installed this winter) was a 1-finger brake, and had great 'feel' in the wet as well. Mine had 2 of the K0-K2 calipers with a hand-modified right-leg "C" mount. This time I will use a "tee" mount from a K3 front end instead, as it will mount the pucks more vertically than my old one did.

[Don R]

 My K0 hot rod needs more brake for sure. I've been hoping someone would cnc some right side early brake brackets but I'm ready to cut up a stock one.

 I owned an F1 with an extra stock brake, stainless lines and a stock M/C. I loved the way it stopped and hope to own another triple disc 750 someday. I most likely ruined a front tire practicing panic stops. My beater 79 goldwing stops pretty good with new organic pads.

[DH]

If you want to really improve the front brakes, add a second disc. I've had twin iron rotors with 38mm calipers and sintered pads, a single iron rotor with a stock K7 caliper and pads, and am currently using twin thin stainless rotors with K7 calipers and pads, all with a stock 14mm master. The original twin iron rotor setup was downright grippy, the single iron rotor setup left me wanting more brake, and the current setup is just right.

That's been my experience, too, Scottly! My 2-disc setup (about to get re-installed this winter) was a 1-finger brake, and had great 'feel' in the wet as well. Mine had 2 of the K0-K2 calipers with a hand-modified right-leg "C" mount. This time I will use a "tee" mount from a K3 front end instead, as it will mount the pucks more vertically than my old one did.

Doing this exact thing to my k5 this week. Have a stock "T" style caliper and bracket mounted on the right side (from a K6)
I didn't need to file any from the right leg, which has me wondering a bit...All that was needed were select size washers
to space/center the caliper bracket over the rotor.(matched it to the other caliper) Seems too easy compared to what I've read in the archives. I haven't driven the bike yet, I take pipes off in winter for storage, but the brakes seem very powerful just rolling the bike around, like they have power assist. Stock master cyl works well. Curious to see how yours turn out.

[OldSchool_IsCool]

New brake lines make a very noticeable difference vs 40 year old originals.

+1

Prolly the single most cost-effective change you can make to improve brake performance.

[DaveBarbier]

If you want to really improve the front brakes, add a second disc. I've had twin iron rotors with 38mm calipers and sintered pads, a single iron rotor with a stock K7 caliper and pads, and am currently using twin thin stainless rotors with K7 calipers and pads, all with a stock 14mm master. The original twin iron rotor setup was downright grippy, the single iron rotor setup left me wanting more brake, and the current setup is just right.

That's been my experience, too, Scottly! My 2-disc setup (about to get re-installed this winter) was a 1-finger brake, and had great 'feel' in the wet as well. Mine had 2 of the K0-K2 calipers with a hand-modified right-leg "C" mount. This time I will use a "tee" mount from a K3 front end instead, as it will mount the pucks more vertically than my old one did.

Doing this exact thing to my k5 this week. Have a stock "T" style caliper and bracket mounted on the right side (from a K6)
I didn't need to file any from the right leg, which has me wondering a bit...All that was needed were select size washers
to space/center the caliper bracket over the rotor.(matched it to the other caliper) Seems too easy compared to what I've read in the archives. I haven't driven the bike yet, I take pipes off in winter for storage, but the brakes seem very powerful just rolling the bike around, like they have power assist. Stock master cyl works well. Curious to see how yours turn out.

Lucky. I needed to use shims for the right fork and shave the bosses down about 3mm on the left fork. All worked out in the end though but math was needed.

[HondaMan]

My K0 hot rod needs more brake for sure. I've been hoping someone would cnc some right side early brake brackets but I'm ready to cut up a stock one.

 I owned an F1 with an extra stock brake, stainless lines and a stock M/C. I loved the way it stopped and hope to own another triple disc 750 someday. I most likely ruined a front tire practicing panic stops. My beater 79 goldwing stops pretty good with new organic pads.

You can use one of the TEE type from the K3 and later bikes. It fits the same holes on the fork leg.

[BobbyR]

My K0 hot rod needs more brake for sure. I've been hoping someone would cnc some right side early brake brackets but I'm ready to cut up a stock one.

 I owned an F1 with an extra stock brake, stainless lines and a stock M/C. I loved the way it stopped and hope to own another triple disc 750 someday. I most likely ruined a front tire practicing panic stops. My beater 79 goldwing stops pretty good with new organic pads.

You can use one of the TEE type from the K3 and later bikes. It fits the same holes on the fork leg.

If I were to get a MC that generated more pressure on the caliper, would that do the trick?

[scottly]

My K0 hot rod needs more brake for sure. I've been hoping someone would cnc some right side early brake brackets but I'm ready to cut up a stock one.

You can use one of the TEE type from the K3 and later bikes. It fits the same holes on the fork leg.

You CAN'T use a "TEE" type caliper mount on early fork legs. A "C" type caliper mount is needed. Don, IIRC, some material needs to be removed from one mounting boss, and spacers added to the other two bosses? It's been documented somewhere here..

[scottly]

If I were to get a MC that generated more pressure on the caliper, would that do the trick?

It would help. With a single 38mm caliper and a 14mm MC, the hydraulic "leverage" ratio is 7.367:1. With a single 38mm caliper and a 12.7mm MC, it would be a ratio of 8.953:1. A 10mm MC would bump this up to 14.44:1, or near the same as twin 38mm calipers with a 14mm MC. The line pressure with the 10mm MC would be twice that of a 14mm MC, for the same pressure applied to the hand lever.

[rotortiller]

I have done both the smaller master piston and caliper thing on another single disk bike individually and together. The smaller 13mm master piston made a difference in modulation and increased braking slightly. Changing to a modern caliper with larger brake liner surface with 2 caliper pistons made a giant difference on a single OEM SS disk. It stops like a modern bike and will lift the back wheel. It is on an 72 H1. Now doing an H2 the same way. The Honda could be adapted to something similar with an adapter bracket I'd think. You can get 13mm piston master with integrated mirror mount for 80 bucks at Parts n More.



rt

[spotty]

the sohc4 pivoting caliper is never gonna be as good as a floating or opposed piston caliper.  Props to Honda for first disc on a production bike, but the engineering is just not capable of what later designs are.

unfortunately not true, honda may have given us the first hydraulic disc brake but it was lambretta in 1962 that had the first disc on a two wheeler (either the GT/TV 175 or 200, can't remember off the top of my head which it was) it was also the first disc inside a hub beating the VT250/400/500 by about 20 years, and for good measure was also a full floating disc

[buffalogt750]

I have done both the smaller master piston and caliper thing on another single disk bike individually and together. The smaller 13mm master piston made a difference in modulation and increased braking slightly. Changing to a modern caliper with larger brake liner surface with 2 caliper pistons made a giant difference on a single OEM SS disk. It stops like a modern bike and will lift the back wheel. It is on an 72 H1. Now doing an H2 the same way. The Honda could be adapted to something similar with an adapter bracket I'd think. You can get 13mm piston master with integrated mirror mount for 80 bucks at Parts n More.



rt

What he said. I think the biggest problem with the old Honda brake system is the antiquated swinging caliper which seems to have been designed by Rube Goldberg himself. Here's late model Kawasaki KLR650 twin piston caliper and master cylinder mounted on a CB550 using the stock disc. Very light weight setup gives modern bike stopping power. Stock KLR650 brake pads are HH sintered pads. Caliper brackets are made from simple aluminum plate with no machining required. Stock mirror fits the master cylinder and caliper was small enough to leave the fender brace intact. I sold the stock parts for more than I paid for the new parts. Lots of options available on ebay for cheap.

[HondaMan]

One thing to keep in mind when increasing the front brake's stopping power: the spokes on the front wheel are very long, and not too thick! Most 2-disc setups from factories came on spoked or mag wheels.

[RRRToolSolutions]

Guys, I'm going to be happy just to have one of the accordion pleats of my fork boots move! I'm not sure that my stock disk/pad set-up even knocks the dust off.

I will install Bronze Sintered pads first and move on to having the disc surfaced on a flywheel machine, and then braided lines as a last resort. I want the brakes to work half as good as the engine -

Thanks for the great inputs! Gordon

[Don R]

Spoked wheels and double discs, so that's why my F1 went ting ting ting whenever I moved it! LOL! I did need to tune the spokes a couple times.

[BobbyR]

Guys, I'm going to be happy just to have one of the accordion pleats of my fork boots move! I'm not sure that my stock disk/pad set-up even knocks the dust off.

I will install Bronze Sintered pads first and move on to having the disc surfaced on a flywheel machine, and then braided lines as a last resort. I want the brakes to work half as good as the engine -

Thanks for the great inputs! Gordon

I mean this with all good intentions. Why would you you not put new braided lines on as part of the brake upgrade. You won't get the best result with the old rubber lines.

[buffalogt750]

Guys, I'm going to be happy just to have one of the accordion pleats of my fork boots move! I'm not sure that my stock disk/pad set-up even knocks the dust off.

I will install Bronze Sintered pads first and move on to having the disc surfaced on a flywheel machine, and then braided lines as a last resort. I want the brakes to work half as good as the engine -

Thanks for the great inputs! Gordon

I mean this with all good intentions. Why would you you not put new braided lines on as part of the brake upgrade. You won't get the best result with the old rubber lines.

+1. Braided brake lines are definitely not a last resort. Here's a pic of the old parts I sold after I upgraded my brake system. Notice the 5 different sets of brake pads I tried in an attempt to get good brakes. The best stopping pads were EBC semi sintered but they will always announce your arrival because they squeal like a stuck pig. The best setup I had on my 550 using the stock caliper was EBC semi sintered pads, braided line, drilled disc and 1/2 inch (12.7mm) master cylinder. The smaller master cylinder is very important and will add power and feel to a single disc setup and is a very easy upgrade.

[Wobbly]

Spoked wheels and double discs, so that's why my F1 went ting ting ting whenever I moved it!

Spoked wheels and double discs: A real problem indeed.

[RAFster122s]

Gordon, what kind of oil are you running in your forks to not see the forks compress? Maybe you need to attend to that...
I guess you mean compress from braking, not hitting bumps and dips in the road...


Dual disk can be done and you have several mods to make it happen and retain the stock speedo drive. Braided lines really help give you good feel and that and drilled rotors are very good combination. Then it is a matter of caliper bore size to give you the desired brake feel.
But, if we are talking 550 you have limit selection with the stock forks. Now if you want to spend about $1000 or more you could do a conversion like FunJimmy and put a early 2000s Yam R1 or FJ6 front forks on the bike. The later top triple is compatible with several of the R1 RSU forks and the FJ6 used handlebars...
So, you have floating disc and 4 pot FJ6 caliper bolts right up, don't even need dual calipers unless you want to deal with too much brake. Pick up used calipers and rebuild them and like Jimmy use the honda CBR 600 floating disc and trim the caliper back to clear the spokes if going with the 18" front wheel... Not sure how much the 19" needs as I haven't finished my conversion and I'm sticking with the 19" stock rim size.


David.

[RRRToolSolutions]

Guys, my forks do compress and I have "ok" brakes. I am guilty of exaggerating at times. I want awesome, or as close to that as I can get. As I get older, the issue of safety gets more and more important. For example, I won't ride without a helmet, boots, armored jacket and pants, and gloves. Next to gear, I consider brakes to be the #3 most important safety equipment. Having the right state of mind, consistent defensive attitude, practice and execution of stopping and avoidance maneuvers to avoid the objects that get in front of us is #1.

Attitude is #1 with me. I don't ride to clear my mind, I won't get on a bike if I can't put 100% of my attention to it. I love riding, touring, and discovery of new roads and landscapes from the seat of a motorcycle. I know there is a single-disc solution out there. My 100% Stock KZ900 single disc is that awesome I'm looking for. The Honda is much faster and quicker than the KZ900 with half the brake.

I don't like braided lines - their looks turn me off. I posted here originally in hopes someone had a magic rotor/disc and/or pad combination. I knew the poor performance was the fault of the Stainless Steel alloy Honda used in the Disc. I would love to find a set of 1970's Sintered Race Pads. Those that would chew/bite the disc like a bear. It's all about the friction and we need to double the amount of it.

Thanks for the inputs. Gordon/RTS

[RAFster122s]

Slingshot Cycle (I think that's their name) can provide a black braided line, or make you new rubber lines for your bike. They are good people and can supply what you need. They are a SOHC4 member and have a link in the services available section and if you mention the SOHC4 membership and provide your user name they can give you I think it was 5% off orders.
New lines will hep...
I knew you were joking and like you, I take safety as very important and agree with everything you said. ATGATT is a good attitude to have. I would ride in the same less the armored pants even in 100F heat of southern AZ...Sure I was roasting unless moving very well and sometimes despite having a mesh armored jacket, and even then when temps above 100 it was sweating all the time. But, that's the price of living in paradise.


David

[scottly]

It's all about the friction and we need to double the amount of it.

Thanks for the inputs. Gordon/RTS

That's why so many of us recommend dual front discs, using stock parts.

[RAFster122s]

Maybe there is a market for new rotors in a better alloy or material. Problem I see with that solution is price not to mention increased wear to the rotor will cause replacement being required in short order. But, the price of safety is hard to put a price tag on...