Topic: Brake pads...that old chestnut.

[Old Moe Toe]

From what I can gather it is hard to beat the original asbestos brake pads for stopping power in wet or dry and also they do not tend to squeal.
It also seems that the sintered ones with the coppery flecks in them work a bit better than the useless organic ones but they tend to squeal.
I have done a twin disc conversion on my 750K2 and am still mighty underwhelmed with the stopping power.
Cant really remember what pads I put in it when I did the conversion but they are not the good ones.(if they even exist)
I see that  Yamiya  has got a slightly dearer type of "AP Racing pads" for sale that have the coppery flecks in them. Also notice these pads do not have a chamfered edge.
Wondering if anyone has used these and what they think, or if there is suddenly some fantastic new pad out there that works very well?.
Or if you have a couple of sets of the original asbestos ones you want to sell?

[Terry in Australia]

The asbestos ones are sh1t mate, I bought my first CB750 new, (a shiny yellow F) and the were rubbish then, we were flinging those fcukers and replacing them with EBC(?) sintered pads back then!

Are you running braided lines? You lose some "feel" with them, but you get a little bit better braking with them as there's no "hose swell" like you get with OM rubber hoses.

The biggest and best thing you can do though, is chuck your MC and replace it with something modern, I like OEM Suzuki Bandit 1200 MC's, I put them on my CB750 dual brake setup, and on my old FJ1200, and the difference is night and day. The OEM MC is rubbish, as are early Goldwing MC's, compared to modern kit. Cheers, Terry.

[540nova]

+1 everything Terry in Australia said.


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[becken]

Using the advice given to me by Michael at http://www.vintagebrake.com I got my 550 to stop like a very much more modern bike, and with a single disc.

[scottly]

The biggest and best thing you can do though, is chuck your MC and replace it with something modern, I like OEM Suzuki Bandit 1200 MC's, I put them on my CB750 dual brake setup, and on my old FJ1200, and the difference is night and day. The OEM MC is rubbish, as are early Goldwing MC's, compared to modern kit. Cheers, Terry.

I don't agree, Tez. I've found the stock 14mm MC's work very well with dual calipers. Most "modern" MC's are 5/8" or larger, and lack the hydraulic leverage needed for the Honda calipers with their small pad area.
Moe, make sure your pads are sitting flat against the rotor surface.

[Vin750]

Moe, make sure your pads are sitting flat against the rotor surface.

If they are not sitting flat, what do you do to fix that? Mine don't seem to be flat.



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[Terry in Australia]

The biggest and best thing you can do though, is chuck your MC and replace it with something modern, I like OEM Suzuki Bandit 1200 MC's, I put them on my CB750 dual brake setup, and on my old FJ1200, and the difference is night and day. The OEM MC is rubbish, as are early Goldwing MC's, compared to modern kit. Cheers, Terry.

I don't agree, Tez. I've found the stock 14mm MC's work very well with dual calipers. Most "modern" MC's are 5/8" or larger, and lack the hydraulic leverage needed for the Honda calipers with their small pad area.
Moe, make sure your pads are sitting flat against the rotor surface.

No, it's actually the opposite Scott, most modern MC's are smaller piston/longer stroke items, that work very well with our old calipers. By "modern" I mean bikes built in the 1990's and later. If you could try the front brakes on my bike you'd wonder why you hadn't done it years ago. Cheers, Terry.

[scottly]

Terry, it's not enough to say "modern", without mentioning the MC piston size. I've used stock 14mm MC's with both dual disc K1 38mm calipers and K7/8 42.8mm calipers, and the stock MC works well. The stock swinging calipers are the #$%*ty part of the system, IMHO, as the pads don't usually sit flat on the rotor until half worn out, unless special care is taken fitting them, and they have less surface area than more modern, floating calipers.
Vin, loosen the caliper mounting bolts on the fork lower, and squeeze the MC lever; the caliper will align itself with the pads flat on the rotor. If the pads are new, the mount may pull away from the fork lower, indicating the need for shims under the mounting bracket.

[Terry in Australia]

Sorry Scott, I'm 400 miles away from my bike, so it's a bit hard to go and check?

It's interesting that you say the OEM MC works well with a dual disc setup on a CB750, you're the first person that I think I've ever heard say that, but it may be that since the 1970's when we used to throw them away and fit GW MC's as part of the conversion, (which were only marginally better) the advent of braided lines and better quality pads has made up for their deficiencies?

"Modern" MC's are obviously much better than 1970's fare, I installed a GSXR750 MC (no idea what the piston size is, but I'm sure you can google it if you like) on my first BMW R100RS along with Brembo twin piston calipers, and on my first time out, inadvertently performed a "stoppie" and lifted my rear wheel off the ground when a car stopped in front of me with no notice and no brake lights working.

You're dead right that the stock calipers are the biggest culprit, but due to Honda's ancient design, they're also the hardest component in the brake "train" to replace, so that's why it's important to try to make everything else work as efficiently as possible.

I've got a similar problem with my 1994 Harley Sportster, similar to the problem I had on my shiny new CB750F back in the 1970's, the rear brake with it's twin piston caliper totally overwhelms the single piston front puck. I thought I'd found the answer with a used PM 4 piston caliper, but the caliper body just touches the spokes, and I don't have enough room to space the disc out further from the hub.

I did remember that I've got a box full of old Brembo twin piston calipers out in my garage though, so I might see what I can do with one this weekend when I'm back home. Cheers, Terry.

[becken]

The only Honda 750 at Daytona in 1976 had dual discs with stock calipers and the stock single cylinder master cylinder. I don't know what pads or brake hoses he was running, but he said there was more travel in the lever and the braking was very much improved.

[Rookster]

I have found the stock master cylinder works well with dual disks also.

Scott

[Don R]

 On my 76F I added a second front brake and used the stock M/C. It had more travel but I found it to work quite well and liked the braking feel even with stock (sanded) pads. The lower hoses were aftermarket braided.

[Don R]

 For giggles I bought a set of Kevlar pads off Ebay. I haven't tried them yet, I guess because they were cheap and I'm having second thoughts.

[Old Moe Toe]

Thank you for the replies.
I did get braided brake lines made up for the twin disc conversion and also bought a brand new goldwing master cylinder from DSS to deal with the twin calipers. Maybe that was a stupid move if the stock master cylinder is meant to still work well with the twin discs. To be fair the stock master cylinder did not work well when it was a single disc set up but there was a fault in the original caliper which has since been thrown out.
Guess I should first try the stock master cylinder with the twin discs and if that shows no improvement go shopping for something more modern.

[becken]

http://www.vintagebrake.com/mastercylinder.htm
Use this chart to figure out what size master cylinder to use for whatever caliper(s) you are using. Michael is very easy to work with and very knowledgeable.

[Terry in Australia]

Thank you for the replies.
I did get braided brake lines made up for the twin disc conversion and also bought a brand new goldwing master cylinder from DSS to deal with the twin calipers. Maybe that was a stupid move if the stock master cylinder is meant to still work well with the twin discs. To be fair the stock master cylinder did not work well when it was a single disc set up but there was a fault in the original caliper which has since been thrown out.
Guess I should first try the stock master cylinder with the twin discs and if that shows no improvement go shopping for something more modern.

Contrary to the posts above, I still maintain that that OEM MC is crap mate, so don't feel bad for throwing yours away. The GW one will work better as it was designed for dual discs, but a modern MC will work better again. Cheers, Terry.

[Old Moe Toe]

Thank you for the replies.
I did get braided brake lines made up for the twin disc conversion and also bought a brand new goldwing master cylinder from DSS to deal with the twin calipers. Maybe that was a stupid move if the stock master cylinder is meant to still work well with the twin discs. To be fair the stock master cylinder did not work well when it was a single disc set up but there was a fault in the original caliper which has since been thrown out.
Guess I should first try the stock master cylinder with the twin discs and if that shows no improvement go shopping for something more modern.

Contrary to the posts above, I still maintain that that OEM MC is crap mate, so don't feel bad for throwing yours away. The GW one will work better as it was designed for dual discs, but a modern MC will work better again. Cheers, Terry.

Well the Goldwing one is ordinary at best even though it is a brand new replica one. (funny how much money one throws away on bikes).
You say your GSXR one works well on your BMW Terry. Does that one have the same size thread on the master cylinder banjo bolt as the original Honda sohc threads?. Also what year and model GSXR was the item from?.
Sorry about the questions, just having a run of bad luck with another old bike and am wary of buying wrong stuff.

[Terry in Australia]

The one on my CB750 is a Suzuki 1200 Bandit MC Mate, just as powerful as the GSXR1100 MC I had on the BM, but the bandit one is better for our bikes as the GSXR1100 item has a remote reservoir which requires you to make a special bracket. Buy an OEM one off a low mileage bike (some Chinese knockoffs are good, but I worry about the availability of parts for them) and the Bandit ones can be had on EBay for under 100 bucks. Cheers, Terry.

[Terry in Australia]

Ooh, some banjo bolts are a course thread, and I don't remember which type the Bandit MC's use, but if you get stuck let me know, I've got a few laying around. Cheers, Terry.

[scottly]

Contrary to the posts above, I still maintain that that OEM MC is crap mate, so don't feel bad for throwing yours away. The GW one will work better as it was designed for dual discs, but a modern MC will work better again. Cheers, Terry.

Terry, size, not age, matters, at least in this case. Moe, what is the size of the GW MC? If it's like the late dual disc 750F, it's 17.5mm, which is way too big for the early 38mm calipers.

[grcamna2]

When the master cyl. has a smaller piston the lever travels further but it creates more hydraulic pressure and the brake bites harder toward the end of the lever's travel.What is the stock size of the master cyl. piston in an oem 76' CB550 ?

[Old Moe Toe]

Contrary to the posts above, I still maintain that that OEM MC is crap mate, so don't feel bad for throwing yours away. The GW one will work better as it was designed for dual discs, but a modern MC will work better again. Cheers, Terry.

Terry, size, not age, matters, at least in this case. Moe, what is the size of the GW MC? If it's like the late dual disc 750F, it's 17.5mm, which is way too big for the early 38mm calipers.

Hi Scotty. Hard to say exactly with out taking off the lever then removing the rubber boot. However I compared it to the stock master cylinder and the Goldwing one is definately larger dia. I would guess 17.5mm would be right.
Will put the original master cylinder back on and see if it improves things, sure can't make it any worse. Failing that I will go shopping for the Suzuki Bandit number.

[RAFster122s]

Sorry Scott, I'm 400 miles away from my bike, so it's a bit hard to go and check?

It's interesting that you say the OEM MC works well with a dual disc setup on a CB750, you're the first person that I think I've ever heard say that, but it may be that since the 1970's when we used to throw them away and fit GW MC's as part of the conversion, (which were only marginally better) the advent of braided lines and better quality pads has made up for their deficiencies?

"Modern" MC's are obviously much better than 1970's fare, I installed a GSXR750 MC (no idea what the piston size is, but I'm sure you can google it if you like) on my first BMW R100RS along with Brembo twin piston calipers, and on my first time out, inadvertently performed a "stoppie" and lifted my rear wheel off the ground when a car stopped in front of me with no notice and no brake lights working.

You're dead right that the stock calipers are the biggest culprit, but due to Honda's ancient design, they're also the hardest component in the brake "train" to replace, so that's why it's important to try to make everything else work as efficiently as possible.

I've got a similar problem with my 1994 Harley Sportster, similar to the problem I had on my shiny new CB750F back in the 1970's, the rear brake with it's twin piston caliper totally overwhelms the single piston front puck. I thought I'd found the answer with a used PM 4 piston caliper, but the caliper body just touches the spokes, and I don't have enough room to space the disc out further from the hub.

I did remember that I've got a box full of old Brembo twin piston calipers out in my garage though, so I might see what I can do with one this weekend when I'm back home. Cheers, Terry.

Brent shaved a bit off his caliper to allow it to fit properly with the 18" wider rim on his race bike. Odds are you could do a bit of that for your PM4 caliper without risking breaching a passage or integrity of the caliper.

David

[PeWe]

Low price CB750 replacement MC from David Silver seems to work. I have not that long experience yet since I have got caliper leakage on left side, right caliper is OK. Maybe too hard pressure from MC and steel braided lines?

[Terry in Australia]

Sorry Scott, I'm 400 miles away from my bike, so it's a bit hard to go and check?

It's interesting that you say the OEM MC works well with a dual disc setup on a CB750, you're the first person that I think I've ever heard say that, but it may be that since the 1970's when we used to throw them away and fit GW MC's as part of the conversion, (which were only marginally better) the advent of braided lines and better quality pads has made up for their deficiencies?

"Modern" MC's are obviously much better than 1970's fare, I installed a GSXR750 MC (no idea what the piston size is, but I'm sure you can google it if you like) on my first BMW R100RS along with Brembo twin piston calipers, and on my first time out, inadvertently performed a "stoppie" and lifted my rear wheel off the ground when a car stopped in front of me with no notice and no brake lights working.

You're dead right that the stock calipers are the biggest culprit, but due to Honda's ancient design, they're also the hardest component in the brake "train" to replace, so that's why it's important to try to make everything else work as efficiently as possible.

I've got a similar problem with my 1994 Harley Sportster, similar to the problem I had on my shiny new CB750F back in the 1970's, the rear brake with it's twin piston caliper totally overwhelms the single piston front puck. I thought I'd found the answer with a used PM 4 piston caliper, but the caliper body just touches the spokes, and I don't have enough room to space the disc out further from the hub.

I did remember that I've got a box full of old Brembo twin piston calipers out in my garage though, so I might see what I can do with one this weekend when I'm back home. Cheers, Terry.

Brent shaved a bit off his caliper to allow it to fit properly with the 18" wider rim on his race bike. Odds are you could do a bit of that for your PM4 caliper without risking breaching a passage or integrity of the caliper.

David

Thanks David, the PM caliper is quite narrow and without disassembling it, I'm gonna say that to remove 3 or 4mm I'd be pushing it to the limit. There is a 4 piston caliper on ebay that is supposed to fit my Sporty, trouble is, I think it's to suit alloy wheels, not spoked suckers.

It's a pity there's not a shop around here that sells them so I could just try it before I handed over the money only to find that it might not fit. I think the Brembo's might be able to be milled considerably though, and anyway, I've got a whole box full of them that I bought 15 or 16 years ago, so if I mess one up, no biggie. Cheers, Terry.