Author Topic: Vintage Disc Brakes with Modern Performance - How to Accomplish?  (Read 23011 times)

0 Members and 3 Guests are viewing this topic.

Offline johnyvilla

  • Hot Shot
  • ***
  • Posts: 516
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #50 on: December 15, 2008, 06:28:21 AM »
Other than bar diameter, are there other guidelines for plucking master cylinders from used bikes? Can I assume a m/c meant for dual disc will not work properly with our stock single set up?

Offline bert96

  • past ride
  • Expert
  • ****
  • Posts: 1,388
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #51 on: December 15, 2008, 04:22:06 PM »


 I forgot to said that you need to drill new bolt holes because the bolt pattern from the VTR is not the same.
QA50 1969,ST-90 1974,mb5 1982,rz350 1983,shadow 1100 1985,vf1000f 1985,BMW K1 1990,shadow tourer 1100 2001,vfr 750 1994,vtr250 199?

Online HondaMan

  • Someone took this pic of me before I became a
  • Really Old Timer ...
  • *******
  • Posts: 13,882
  • ...not my choice, I was nicknamed...
    • Getting 'em Back on the Road
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #52 on: December 15, 2008, 08:10:51 PM »
I've got drilled dual discs, stainless braided lines and an F2 MC on my K1, and they work very well indeed, wet or dry. While I was waiting for the F2 MC rebuild Kit I used a late model Suzuki GSXR1000 MC, and it worked even better, but looked kinda weird on a laid back "Kruiser".

What's the difference between an older MC with a larger than standard piston (i.e., my set up) and a modern MC with a smaller piston, but longer stroke? Cheers, Terry. ;D



The smaller master cylinder's piston increases your grip ratio, or leverage, hydraulically. However, the amount of fluid that's moving must remain the same, so the angles of the lever are changed, usually by moving the pivot further away from you (and the handlebar) and adding a curved, sliding surface to the inboard side of the lever. It sort of rolls in against the piston this way, which often makes the newer ones wear faster from the sideways loading. Honda's racing (Yosh) masters were made this way, even in the 1970s, but I think stock Hondas went the "push-in" route for long-term reliability, and because they weren't really sure how hard people would grab the brake. The straight-in push of the stock cylinders makes for very little master piston wear, and it takes a gorilla grip with the stock piston ratios to lock up the front brake and wheel.

There was special "training" literature given to the first K0 buyers about "easing into the use of the powerful front disc brake by testing it in an empy parking lot and on wet surfaces before riding in close traffic". It was a 2-page bulletin, just typewritten with the Honda logo on the top of it (we had one hanging on the shop wall where customers could read it). Honda was obviously concerned about it, but I could never lock my front brake until I added the second caliper. Of course, then it took 2 fingers to slide the front right out from under me, and my alternator cover and left rear footpeg made its first 3-point touchdown debut! It was sure nice in the race corners, and on the wet roads of Washington and Oregon, though, as I kept them very close to the discs (.003" clearance) to minimize the lever travel, and this swept most of the water away. The disc must be perfectly flat for this to work, and some are not, especially on the K4-later bikes. I noticed several K4/5 bikes that had slightly warped rotors, brand new out of the crate, in 1974-5.
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Offline bert96

  • past ride
  • Expert
  • ****
  • Posts: 1,388
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #53 on: December 16, 2008, 04:48:33 AM »
Bert96, you said " My bike is a cb750 k4 and the only mod needed to do this swap is to remove a couple of MM on the center of the disc it's almost a plug and play!  You need to modified the brake pad though."

Could you elaborate on how the brake pad (or caliper assembly) needs to modified to fit late floating rotors?  Thanks.  RR

Here's the pic,

QA50 1969,ST-90 1974,mb5 1982,rz350 1983,shadow 1100 1985,vf1000f 1985,BMW K1 1990,shadow tourer 1100 2001,vfr 750 1994,vtr250 199?

Offline moham

  • .fnord.
  • Expert
  • ****
  • Posts: 1,108
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #54 on: December 16, 2008, 06:51:36 AM »
I've got drilled dual discs, stainless braided lines and an F2 MC on my K1, and they work very well indeed, wet or dry. While I was waiting for the F2 MC rebuild Kit I used a late model Suzuki GSXR1000 MC, and it worked even better, but looked kinda weird on a laid back "Kruiser".

What's the difference between an older MC with a larger than standard piston (i.e., my set up) and a modern MC with a smaller piston, but longer stroke? Cheers, Terry. ;D



The smaller master cylinder's piston increases your grip ratio, or leverage, hydraulically.

I've read several references to modern, smaller piston MCs in comparison to older, bigger MCs. However, after looking at brembo and AP racing MCs they come in bores of 16, 18, 20 with different travel distances as well. I know on the stock 550K0 the MC piston is 14mm. I don't know about the 750. That seems to suggest the modern MCs (at least these high-priced, well-established ones) are bigger bore than the old, stock unit. Or is it all dependent on the individual MC one eventually chooses? I'm confused. Do I have my numbers wrong? Or am I just a bit slow? (pun intended)...
78 750K-The Ocho
74 550-The Cherry Picker
70 750K0 motor-Dick in a Box

Offline UnCrash

  • Pass
  • Master
  • *****
  • Posts: 1,705
    • My Blog
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #55 on: December 16, 2008, 08:19:01 AM »
Hey Bert,

Would you consider doing more of a detailed write up on this procedure.

Very interesting!!!
You can't make too much popcorn, but you can definately eat too much popcorn.

Offline Terry in Australia

  • Really Old Timer ...
  • *******
  • Posts: 33,321
  • So, what do ya wanna talk about today?
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #56 on: December 16, 2008, 12:27:26 PM »
I've got drilled dual discs, stainless braided lines and an F2 MC on my K1, and they work very well indeed, wet or dry. While I was waiting for the F2 MC rebuild Kit I used a late model Suzuki GSXR1000 MC, and it worked even better, but looked kinda weird on a laid back "Kruiser".

What's the difference between an older MC with a larger than standard piston (i.e., my set up) and a modern MC with a smaller piston, but longer stroke? Cheers, Terry. ;D



The smaller master cylinder's piston increases your grip ratio, or leverage, hydraulically.

I've read several references to modern, smaller piston MCs in comparison to older, bigger MCs. However, after looking at brembo and AP racing MCs they come in bores of 16, 18, 20 with different travel distances as well. I know on the stock 550K0 the MC piston is 14mm. I don't know about the 750. That seems to suggest the modern MCs (at least these high-priced, well-established ones) are bigger bore than the old, stock unit. Or is it all dependent on the individual MC one eventually chooses? I'm confused. Do I have my numbers wrong? Or am I just a bit slow? (pun intended)...

Yeah, I think this must be a relatively new science mate, my understanding has always been that the bigger piston, the quicker it'll pull up, I wasn't aware of the smaller piston, longer travel "big bang" theory, but I understand what Hondaman's saying, and it makes sense.

This technology must be very new, because the 2002 GSXR1000 MC I previously mentioned had a bigger piston than the one in my F2 MC, 19mm, I think? Cheers, Terry. ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline johnyvilla

  • Hot Shot
  • ***
  • Posts: 516
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #57 on: December 16, 2008, 01:19:32 PM »
Two questions Bert:

Did you turn your disc on a lathe to remove material from the center?

And from your picture it looks like you reduced your puck to about 2/3 of its size. Doesn't the decreased surface area of the puck, offset any gains made by using a modern disc? Or does it still stop better?

Thanks

Offline bert96

  • past ride
  • Expert
  • ****
  • Posts: 1,388
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #58 on: December 16, 2008, 01:44:05 PM »
Two questions Bert:

Did you turn your disc on a lathe to remove material from the center?

And from your picture it looks like you reduced your puck to about 2/3 of its size. Doesn't the decreased surface area of the puck, offset any gains made by using a modern disc? Or does it still stop better?

Thanks

 I did not the job myself(i don't have a lathe),but yes you need to.And for the brake pad i don't have the choice to remove a little bit of the pad,if not it will rub on the rivets.But the pad cover all the surface of the rotors.The offset is the same,no problem there.I have two big washer to cover the old bolt pattern because as i said you need to drill six new holes.
I don't know if my explanation is clear but don't hesitate to ask more questions.
QA50 1969,ST-90 1974,mb5 1982,rz350 1983,shadow 1100 1985,vf1000f 1985,BMW K1 1990,shadow tourer 1100 2001,vfr 750 1994,vtr250 199?

Offline voxonda

  • Master
  • *****
  • Posts: 2,231
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #59 on: December 16, 2008, 01:44:53 PM »
Hi Bert,

I am interested in the possible problems with leakage of the piston. My English is not good enough to explain exactly, but it seems to me, from what I see from the picture, the force applied by the piston does not cover the whole surface of the pad ,and so maybe the piston will tilt a bid.
Hope it is understandable what I mean.

Cheers, Rob
Better sorry for failing then for the lack of trying.

Offline bert96

  • past ride
  • Expert
  • ****
  • Posts: 1,388
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #60 on: December 16, 2008, 01:58:28 PM »

I don't think it will be a problem,because the piston don't move much in a caliper.
QA50 1969,ST-90 1974,mb5 1982,rz350 1983,shadow 1100 1985,vf1000f 1985,BMW K1 1990,shadow tourer 1100 2001,vfr 750 1994,vtr250 199?

Offline Terry in Australia

  • Really Old Timer ...
  • *******
  • Posts: 33,321
  • So, what do ya wanna talk about today?
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #61 on: December 16, 2008, 05:15:54 PM »
I'm trying to concentrate on this thread, but Bert's avatar keeps distracting me...............  ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline BobbyR

  • Really Old Timer ...
  • *******
  • Posts: 12,367
  • Proud Owner of the Babe Thread & Dirty Old Man
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #62 on: December 16, 2008, 05:27:39 PM »
Terry, I see what you mean. I have been collecting parts for the dul disc upgrade. I just bought a 750F speedo drive on ebay, just got it tonite. I cannot turn the center of the drive by hand, is this a big problem, or have I been had?
Dedicated to Sgt. Howard Bruckner 1950 - 1969. KIA LONG KHANH.

But we were boys, and boys will be boys, and so they will. To us, everything was dangerous, but what of that? Had we not been made to live forever?

Offline Terry in Australia

  • Really Old Timer ...
  • *******
  • Posts: 33,321
  • So, what do ya wanna talk about today?
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #63 on: December 16, 2008, 06:46:20 PM »
No mate, you haven't been "had", the centre of the drive is a spacer to stop everything being squeezed together when you tighten your axle nut.

You need to inset the drive flange into the actual drive unit and turn it, while watching that the "tang" that the cable slots into is turning. Cheers, Terry. ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline coyotecowboy

  • Hot Shot
  • ***
  • Posts: 406
  • Easily Distracted
    • American Legion Riders Post 69 Medicine Lodge, Ks
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #64 on: December 16, 2008, 07:16:09 PM »
I've got drilled dual discs, stainless braided lines and an F2 MC on my K1, and they work very well indeed, wet or dry. While I was waiting for the F2 MC rebuild Kit I used a late model Suzuki GSXR1000 MC, and it worked even better, but looked kinda weird on a laid back "Kruiser".

What's the difference between an older MC with a larger than standard piston (i.e., my set up) and a modern MC with a smaller piston, but longer stroke? Cheers, Terry. ;D



The smaller master cylinder's piston increases your grip ratio, or leverage, hydraulically.

I've read several references to modern, smaller piston MCs in comparison to older, bigger MCs. However, after looking at brembo and AP racing MCs they come in bores of 16, 18, 20 with different travel distances as well. I know on the stock 550K0 the MC piston is 14mm. I don't know about the 750. That seems to suggest the modern MCs (at least these high-priced, well-established ones) are bigger bore than the old, stock unit. Or is it all dependent on the individual MC one eventually chooses? I'm confused. Do I have my numbers wrong? Or am I just a bit slow? (pun intended)...

Yeah, I think this must be a relatively new science mate, my understanding has always been that the bigger piston, the quicker it'll pull up, I wasn't aware of the smaller piston, longer travel "big bang" theory, but I understand what Hondaman's saying, and it makes sense.

This technology must be very new, because the 2002 GSXR1000 MC I previously mentioned had a bigger piston than the one in my F2 MC, 19mm, I think? Cheers, Terry. ;D


One thing (I think) alot of you guys are forgetting is the newer masters are designed for multi-piston, dual calipers, not our single or dual 38mm single piston calipers.

Interesting reading here>> http://www.vintagebrake.com/index.html

Be sure to look at the Master cylinder ratio chart, and there is quite a bit to read, those guys seem to know their #$%* ;)
The adventure begins when things stop going as planned - Glen Heggstad

http://www.alrpost69.com/

Sunrise Orange 750 K2

1981 Husqvarna 430 XC, "Inga"

Online HondaMan

  • Someone took this pic of me before I became a
  • Really Old Timer ...
  • *******
  • Posts: 13,882
  • ...not my choice, I was nicknamed...
    • Getting 'em Back on the Road
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #65 on: December 16, 2008, 08:26:03 PM »
I've got drilled dual discs, stainless braided lines and an F2 MC on my K1, and they work very well indeed, wet or dry. While I was waiting for the F2 MC rebuild Kit I used a late model Suzuki GSXR1000 MC, and it worked even better, but looked kinda weird on a laid back "Kruiser".

What's the difference between an older MC with a larger than standard piston (i.e., my set up) and a modern MC with a smaller piston, but longer stroke? Cheers, Terry. ;D



The smaller master cylinder's piston increases your grip ratio, or leverage, hydraulically.

I've read several references to modern, smaller piston MCs in comparison to older, bigger MCs. However, after looking at brembo and AP racing MCs they come in bores of 16, 18, 20 with different travel distances as well. I know on the stock 550K0 the MC piston is 14mm. I don't know about the 750. That seems to suggest the modern MCs (at least these high-priced, well-established ones) are bigger bore than the old, stock unit. Or is it all dependent on the individual MC one eventually chooses? I'm confused. Do I have my numbers wrong? Or am I just a bit slow? (pun intended)...

Yeah, I think this must be a relatively new science mate, my understanding has always been that the bigger piston, the quicker it'll pull up, I wasn't aware of the smaller piston, longer travel "big bang" theory, but I understand what Hondaman's saying, and it makes sense.

This technology must be very new, because the 2002 GSXR1000 MC I previously mentioned had a bigger piston than the one in my F2 MC, 19mm, I think? Cheers, Terry. ;D
I think CoyoteCowboy's link above has it pegged. The larger the master cylinder, in comparison to the caliper, the lower the ratio and the harder the brake is to 'feel' until it reacts badly. With a given caliper, it's usually easy to go up or down a size on the master to tailor the effects.

When I had the duals on my 750, it was like having power brakes in a small car: very effective. This essentially doubled the ratio by increasing the caliper size, so the grip ratio, combined with the increased swept area, more than halved the lever force. I had to use Honda's pucks or the EBC non-sintered variety on the duals to prevent front wheel lockup. This was when I learned how much the EBC pucks can glaze and cause squeak, if used too lightly.
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Offline BobbyR

  • Really Old Timer ...
  • *******
  • Posts: 12,367
  • Proud Owner of the Babe Thread & Dirty Old Man
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #66 on: December 16, 2008, 08:30:23 PM »
I've got drilled dual discs, stainless braided lines and an F2 MC on my K1, and they work very well indeed, wet or dry. While I was waiting for the F2 MC rebuild Kit I used a late model Suzuki GSXR1000 MC, and it worked even better, but looked kinda weird on a laid back "Kruiser".

What's the difference between an older MC with a larger than standard piston (i.e., my set up) and a modern MC with a smaller piston, but longer stroke? Cheers, Terry. ;D



The smaller master cylinder's piston increases your grip ratio, or leverage, hydraulically.

I've read several references to modern, smaller piston MCs in comparison to older, bigger MCs. However, after looking at brembo and AP racing MCs they come in bores of 16, 18, 20 with different travel distances as well. I know on the stock 550K0 the MC piston is 14mm. I don't know about the 750. That seems to suggest the modern MCs (at least these high-priced, well-established ones) are bigger bore than the old, stock unit. Or is it all dependent on the individual MC one eventually chooses? I'm confused. Do I have my numbers wrong? Or am I just a bit slow? (pun intended)...

Yeah, I think this must be a relatively new science mate, my understanding has always been that the bigger piston, the quicker it'll pull up, I wasn't aware of the smaller piston, longer travel "big bang" theory, but I understand what Hondaman's saying, and it makes sense.

This technology must be very new, because the 2002 GSXR1000 MC I previously mentioned had a bigger piston than the one in my F2 MC, 19mm, I think? Cheers, Terry. ;D


One thing (I think) alot of you guys are forgetting is the newer masters are designed for multi-piston, dual calipers, not our single or dual 38mm single piston calipers.

Interesting reading here>> http://www.vintagebrake.com/index.html

Be sure to look at the Master cylinder ratio chart, and there is quite a bit to read, those guys seem to know their #$%* ;)
I just emailed the guy, maybe better pads will get some better stopping for me
Dedicated to Sgt. Howard Bruckner 1950 - 1969. KIA LONG KHANH.

But we were boys, and boys will be boys, and so they will. To us, everything was dangerous, but what of that? Had we not been made to live forever?

Offline Terry in Australia

  • Really Old Timer ...
  • *******
  • Posts: 33,321
  • So, what do ya wanna talk about today?
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #67 on: December 16, 2008, 08:35:09 PM »
Did you use the OEM single caliper MC with your dual disc conversion Mark? I did on my K1 28 years ago and it was shiit, I could pull the lever into the handlebars and it still wouldn't pull up, so I converted it to use a CB900F MC with 17mm (?) piston, and it was like night and day, heaps of feel and two finger braking from any speed.

No braided lines back then, but then again, I suspect the braided lines actually enhance the "wooden" feel some folks are experiencing now. Cheers, Terry. ;D
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline voxonda

  • Master
  • *****
  • Posts: 2,231
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #68 on: December 17, 2008, 12:12:54 AM »

I don't think it will be a problem,because the piston don't move much in a caliper.

Let's hope so, seen a lot of damage over the years.

Good luck, Rob
Better sorry for failing then for the lack of trying.

Offline BobbyR

  • Really Old Timer ...
  • *******
  • Posts: 12,367
  • Proud Owner of the Babe Thread & Dirty Old Man
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #69 on: December 17, 2008, 05:50:49 PM »
I've got drilled dual discs, stainless braided lines and an F2 MC on my K1, and they work very well indeed, wet or dry. While I was waiting for the F2 MC rebuild Kit I used a late model Suzuki GSXR1000 MC, and it worked even better, but looked kinda weird on a laid back "Kruiser".

What's the difference between an older MC with a larger than standard piston (i.e., my set up) and a modern MC with a smaller piston, but longer stroke? Cheers, Terry. ;D



The smaller master cylinder's piston increases your grip ratio, or leverage, hydraulically.

I've read several references to modern, smaller piston MCs in comparison to older, bigger MCs. However, after looking at brembo and AP racing MCs they come in bores of 16, 18, 20 with different travel distances as well. I know on the stock 550K0 the MC piston is 14mm. I don't know about the 750. That seems to suggest the modern MCs (at least these high-priced, well-established ones) are bigger bore than the old, stock unit. Or is it all dependent on the individual MC one eventually chooses? I'm confused. Do I have my numbers wrong? Or am I just a bit slow? (pun intended)...

Yeah, I think this must be a relatively new science mate, my understanding has always been that the bigger piston, the quicker it'll pull up, I wasn't aware of the smaller piston, longer travel "big bang" theory, but I understand what Hondaman's saying, and it makes sense.

This technology must be very new, because the 2002 GSXR1000 MC I previously mentioned had a bigger piston than the one in my F2 MC, 19mm, I think? Cheers, Terry. ;D


One thing (I think) alot of you guys are forgetting is the newer masters are designed for multi-piston, dual calipers, not our single or dual 38mm single piston calipers.

Interesting reading here>> http://www.vintagebrake.com/index.html

Be sure to look at the Master cylinder ratio chart, and there is quite a bit to read, those guys seem to know their #$%* ;)
I just emailed the guy, maybe better pads will get some better stopping for me

I recieved a response to my email, I like this outfit. Here is what he wrote:

It all starts with the pads. K0-K5, I have a Borg-Warner race compound that works well on the
street, or the EBC Black. For the later caliper. I have the Ferodo Platinums. After a SS line, the
next biggie is an 10 or 11mm master cylinder, for a more modern leverage ratio. Mark McGrew of M3 Racing, used the B-W pads and  an 11mm MC for racing his personal bike with single disc and was quite pleased.

Sincerely,
Michael "Mercury" Morse

650 Central
http://www.650central.com/

Vintage Brake
15069 Lupine Lane
Sonora, CA 95370
ph/fax (209) 533-4346
http://www.vintagebrake.com
Dedicated to Sgt. Howard Bruckner 1950 - 1969. KIA LONG KHANH.

But we were boys, and boys will be boys, and so they will. To us, everything was dangerous, but what of that? Had we not been made to live forever?

Offline moham

  • .fnord.
  • Expert
  • ****
  • Posts: 1,108
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #70 on: December 17, 2008, 07:25:50 PM »
After a SS line, the next biggie is an 10 or 11mm master cylinder, for a more modern leverage ratio. Mark McGrew of M3 Racing, used the B-W pads and  an 11mm MC for racing his personal bike with single disc and was quite pleased.

Yea, looking at the chart for a 750 caliper to land in his suggested ratio would imply a 10 or 11mm MC. When I was looking at it this morning I was scratching my head at that, but I guess there's your proof. Thanks to the cat posting the ratio chart and thanks to you for the follow-up. Perhaps the brake update for my 550 will now be bit better informed.
78 750K-The Ocho
74 550-The Cherry Picker
70 750K0 motor-Dick in a Box

Online HondaMan

  • Someone took this pic of me before I became a
  • Really Old Timer ...
  • *******
  • Posts: 13,882
  • ...not my choice, I was nicknamed...
    • Getting 'em Back on the Road
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #71 on: December 17, 2008, 08:07:50 PM »
Did you use the OEM single caliper MC with your dual disc conversion Mark? I did on my K1 28 years ago and it was shiit, I could pull the lever into the handlebars and it still wouldn't pull up, so I converted it to use a CB900F MC with 17mm (?) piston, and it was like night and day, heaps of feel and two finger braking from any speed.

No braided lines back then, but then again, I suspect the braided lines actually enhance the "wooden" feel some folks are experiencing now. Cheers, Terry. ;D

Yes, I did use the Honda master cylinder, but I also reduced the static puck's clearances to .003" from the discs. With the Honda pucks, the materials would glaze after 2000 miles or so, and they would not stop real well, and would squeal. I then took to cutting large, deep "X" in the faces of them and bevelling the edges, and they got much better for about 5000 miles, then did it again. I could lock the front until this glazing, squealing bit started, then I couldn't. Switching to the sintered EBC pucks of the day make a real strong, 2-fingered brake, almost too strong for street, as I would sometimes find myself sliding on the oily stuff at stoplights (I seldom use my rear brake at all). But, I adapted and ran with the sintered EBCs untilI had to take off the extra disc and sell it for newlywed cash when I got married.  :-\

I may have to go back. My grip is as weak as my back now, you know...  ;D
See SOHC4shop@gmail.com for info about the gadgets I make for these bikes.

The demons are repulsed when a man does good. Use that.
Blood is thicker than water, but motor oil is thicker yet...so, don't mess with my SOHC4, or I might have to hurt you.
Hondaman's creed: "Bikers are family. Treat them accordingly."

Link to Hondaman Ignition: http://forums.sohc4.net/index.php?topic=67543.0

Link to My CB750 Book: https://www.lulu.com/search?adult_audience_rating=00&page=1&pageSize=10&q=my+cb750+book

Link to website: www.SOHC4shop.com

Offline BobbyR

  • Really Old Timer ...
  • *******
  • Posts: 12,367
  • Proud Owner of the Babe Thread & Dirty Old Man
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #72 on: December 17, 2008, 08:22:08 PM »
Did you use the OEM single caliper MC with your dual disc conversion Mark? I did on my K1 28 years ago and it was shiit, I could pull the lever into the handlebars and it still wouldn't pull up, so I converted it to use a CB900F MC with 17mm (?) piston, and it was like night and day, heaps of feel and two finger braking from any speed.

No braided lines back then, but then again, I suspect the braided lines actually enhance the "wooden" feel some folks are experiencing now. Cheers, Terry. ;D

Yes, I did use the Honda master cylinder, but I also reduced the static puck's clearances to .003" from the discs. With the Honda pucks, the materials would glaze after 2000 miles or so, and they would not stop real well, and would squeal. I then took to cutting large, deep "X" in the faces of them and bevelling the edges, and they got much better for about 5000 miles, then did it again. I could lock the front until this glazing, squealing bit started, then I couldn't. Switching to the sintered EBC pucks of the day make a real strong, 2-fingered brake, almost too strong for street, as I would sometimes find myself sliding on the oily stuff at stoplights (I seldom use my rear brake at all). But, I adapted and ran with the sintered EBCs untilI had to take off the extra disc and sell it for newlywed cash when I got married.  :-\

I may have to go back. My grip is as weak as my back now, you know...  ;D
Hondaman,

I think this fellow sells sintered metal pads and shoes.
Dedicated to Sgt. Howard Bruckner 1950 - 1969. KIA LONG KHANH.

But we were boys, and boys will be boys, and so they will. To us, everything was dangerous, but what of that? Had we not been made to live forever?

Offline bert96

  • past ride
  • Expert
  • ****
  • Posts: 1,388
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #73 on: December 18, 2008, 01:32:25 AM »
Is there a difference between cb750 K1-K6 brake pad and cb750K 77-78 pad?
QA50 1969,ST-90 1974,mb5 1982,rz350 1983,shadow 1100 1985,vf1000f 1985,BMW K1 1990,shadow tourer 1100 2001,vfr 750 1994,vtr250 199?

Offline tygrant

  • Hot Shot
  • ***
  • Posts: 323
Re: Vintage Disc Brakes with Modern Performance - How to Accomplish?
« Reply #74 on: December 18, 2008, 06:46:05 AM »
I have been following this thread, on a 75 550f, the stock C piston is 38mm, MC is 14mm, that chart if im reading correctly says i should be running at largest a 12 mm MC... not taking into accout travel... is that correct?
1975 CB550F - cafe
2001 YZF-R6
2002 HD fatboy