Post by: Mikep328 on July 21, 2023, 06:46:08 AM
Subsequently I found this site and read all the posts I could find, seeing much re the "wooden" feel and generally mediocre stopping power. On my bike the lever is firm, no sponginess. It just doesn't apply any real stopping power, regardless of how much pressure I apply on the lever. The bike has 13,276 miles and is in excellent, well serviced condition with a lot of receipts for work done, to include replacing the cam chain tensioner as well as other engine "freshening." The only modification to the bike from stock is an electronic ignition.
I contacted a well-known vintage Honda spares supplier, asking them for recommendations to improve the brake. I was surprised that rather than trying to sell me a new rotor, new lines, new master cylinder, etc), the response was, "New pads may help but the brakes on a CB400F were never great." :(
The front brake feels pretty much the same as the stock front brake did on my '73 Norton Commando - maybe even a bit worse - before I replaced the OEM master cylinder with a Brembo from Colorado Norton Works. That, a set of braided SS lines, and some more aggressive pads in the OEM caliper transformed that brake. It is now acts and feels like modern brakes. Of course the down side is that the master cylinder does not look anything like the OEM version.
My general thought is to go down a similar path though from searching and the suppliers response, it doesn't sound like anything is going to make the sort of transformation I am looking for.
So...I'm wondering if anyone has done something similar (different master cylinder) or found some tricks/tweaks/mods to the OEM front brake that I have not managed to find via the search function. Also, what are the most aggressive brake pads for street riding, including aggressive riding on narrow, twisty roads? I don't care about rotor wear. If I had to replace a rotor every 10,000 miles to get good brakes, that's fine.
Thanks!
Post by: Trigger on July 21, 2023, 07:16:05 AM
It is a 70's bike and they don't have modern braking grip or stopping power. They were just a simple upgrade from a drum brake.
Post by: davidcumbria on July 21, 2023, 07:51:52 AM
Welcome Mike- great forum this.
I have exactly the same diagnosis about my 550k front brake which has a new master cylinder and caliper piston and pads. Pull as hard as I think reasonable with full hand not two fingers and retardation is pathetic- need to use rear brake all the time. Pads did not look especially glazed. My plan is to rebuild with braided lines and to clean the disc very thoroughly.
Also need to check the master cylinder piston diameter which should be 14 mm. Some aftermarket units are 5/8 th inch which is 15.9 mm and that would increase the wooden feel. Also I have read that as a first disc brake effort Honda were worried about lock ups so made it intentionally weak.
A double disc conversion seems quite common on the 500/550 but I do wonder if a smaller diameter mc piston would help. The lever movement is very small so I could cope with more travel. Not seen any recommendations for smaller diameter master cylinders. Agree that safety is a much more important priority than originality.
Post by: Johnny4428 on July 21, 2023, 08:32:57 AM
Post by: Bryanj on July 21, 2023, 08:42:01 AM
Pads will make difference, as will making sure the pivot is free and caliper adjusted, lines might make a small diffeence if yours are original.
Apart from that its just brake earlier!
Post by: Trigger on July 21, 2023, 08:49:01 AM
Its easy to say you dont mind changing rotors but finding one isnt, no aftermarket to my knowledge.
Pads will make difference, as will making sure the pivot is free and caliper adjusted, lines might make a small diffeence if yours are original.
Apart from that its just brake earlier!
Aftermarket are available but, don't know if you can believe Slivers sales pitch >> https://www.davidsilverspares.co.uk/CB400F-SUPER-SPORT-FOUR/part_257875/
Post by: Bryanj on July 21, 2023, 09:06:26 AM
Post by: mickwinf on July 21, 2023, 09:11:01 AM
Post by: Mikep328 on July 21, 2023, 09:23:49 AM
Post by: McCabe-Thiele (Ted) on July 21, 2023, 09:43:31 AM
Post by: Johnny4428 on July 21, 2023, 10:07:58 AM
Its easy to say you dont mind changing rotors but finding one isnt, no aftermarket to my knowledge.
Pads will make difference, as will making sure the pivot is free and caliper adjusted, lines might make a small diffeence if yours are original.
Apart from that its just brake earlier!
Good point Bryan, I have been almost caught out riding along or behind others on modern machines.🥵🥵
Post by: Bryanj on July 21, 2023, 10:09:35 AM
Post by: K2-K6 on July 21, 2023, 10:29:58 AM
agree with your assessment here. Its primarily the hydraulic leverage ratio that makes them feel so wooden and inert.
Welcome Mike- great forum this.
I have exactly the same diagnosis about my 550k front brake which has a new master cylinder and caliper piston and pads. Pull as hard as I think reasonable with full hand not two fingers and retardation is pathetic- need to use rear brake all the time. Pads did not look especially glazed. My plan is to rebuild with braided lines and to clean the disc very thoroughly.
Also need to check the master cylinder piston diameter which should be 14 mm. Some aftermarket units are 5/8 th inch which is 15.9 mm and that would increase the wooden feel. Also I have read that as a first disc brake effort Honda were worried about lock ups so made it intentionally weak.
A double disc conversion seems quite common on the 500/550 but I do wonder if a smaller diameter mc piston would help. The lever movement is very small so I could cope with more travel. Not seen any recommendations for smaller diameter master cylinders. Agree that safety is a much more important priority than originality.
Of their contemporary bikes the Yamaha RD400 had much more potent front brake with significant difference in hydraulic ratio in comparison to Honda's very conservstive approach
The Yamaha used a fixed and twin opposed piston caliper (making similar ratio to two Honda type in double arrangements) that would feel good even now.
Later they went to sliding caliper and single piston but with different master, still potent but lost that absolute rigid bite the old twin pot had.
Changing mastercylinder ratio of the 400 4 should yeald good results, but as pointed out, unlikely to be accomplished with std looking components.
Post by: TrickyMicky on July 21, 2023, 10:31:17 AM
Hi all! A few days ago I acquired a '76 CB400 four, took it out for my first ride. Fun little bike...except for the front brake which I found totally inadequate.. Greetings, and welcome to the forum. People that are brought up with these vehicles were used to the braking standards of the time. The braking power available was quite sufficient for the tyres and other ingredients that were the standard in the 70's, and this included many of the four wheeled vehicles as well. As time passed, engineering and tyre quality improved beyond belief, you had to be bloody brave to try and make rapid progress on a wet road whilst your bike was still wearing its factory fitted Sensitol lubricated tyres!! Moving on to today, you are still riding a historic vehicle, if you want to ride with your knees and arse scraping the floor, then use a modern vehicle. In fact if you want aggressive street riding, along with aggressive riding along narrow country roads, I hope we never meet.
Subsequently I found this site and read all the posts I could find, seeing much re the "wooden" feel and generally mediocre stopping power. On my bike the lever is firm, no sponginess. It just doesn't apply any real stopping power, regardless of how much pressure I apply on the lever. The bike has 13,276 miles and is in excellent, well serviced condition with a lot of receipts for work done, to include replacing the cam chain tensioner as well as other engine "freshening." The only modification to the bike from stock is an electronic ignition.
I contacted a well-known vintage Honda spares supplier, asking them for recommendations to improve the brake. I was surprised that rather than trying to sell me a new rotor, new lines, new master cylinder, etc), the response was, "New pads may help but the brakes on a CB400F were never great." :(
The front brake feels pretty much the same as the stock front brake did on my '73 Norton Commando - maybe even a bit worse - before I replaced the OEM master cylinder with a Brembo from Colorado Norton Works. That, a set of braided SS lines, and some more aggressive pads in the OEM caliper transformed that brake. It is now acts and feels like modern brakes. Of course the down side is that the master cylinder does not look anything like the OEM version.
My general thought is to go down a similar path though from searching and the suppliers response, it doesn't sound like anything is going to make the sort of transformation I am looking for.
So...I'm wondering if anyone has done something similar (different master cylinder) or found some tricks/tweaks/mods to the OEM front brake that I have not managed to find via the search function. Also, what are the most aggressive brake pads for street riding, including aggressive riding on narrow, twisty roads? I don't care about rotor wear. If I had to replace a rotor every 10,000 miles to get good brakes, that's fine.
Thanks!
Post by: Trigger on July 21, 2023, 10:36:27 AM
Interesting info guys, thanks. I had ASSUMED (you know what they say about assumptions) that David Silver was THE place to go for CB400 replacement parts.
Some parts yes, but other a no.
Were are in the UK ? Maybe another member is close to you to compare, as i can get the lever sharp. Also look if it has a new aftermarket brake switch fitted, i have had problems with those recently ;)
Post by: Matt_Harrington on July 21, 2023, 11:09:24 AM
Post by: McCabe-Thiele (Ted) on July 21, 2023, 11:59:30 AM
Post by: Mikep328 on July 21, 2023, 01:04:10 PM
Interestingly, the brakes seemed to improve a bit after some repeated heavy braking from around 85 MPH (indicated). After doing that, they seemed to react a LITTLE bit better. Or maybe I'm already getting used to them. ;) Definitely a fun bike to ride and I was pleasantly surprised with the engine response as the tach passes 6k RPM, heading for red line! :)
Post by: Laverdaroo on July 21, 2023, 01:18:03 PM
(https://uploads.tapatalk-cdn.com/20230721/6f389c670a8275a1702dd5fe6e33b9c5.jpg)Sent from my iPhone using Tapatalk
Post by: Nurse Julie on July 21, 2023, 01:45:04 PM
Definitely a fun bike to ride and I was pleasantly surprised with the engine response as the tach passes 6k RPM, heading for red line! :)Over 6k is where the 400 four is most happy. Anything much less than that is more of a crusing speed and they were not built as cruisers. They just love being thrashed, using high revs in all gears, that is where they perform at their best. Up to the red line is it's happy place 😁😁😁😁
Yes, I know I blew the engine up on Hettie but it really wasn't my fault 😂😂😂😂😂
Post by: davidcumbria on July 21, 2023, 02:13:54 PM
Post by: Mikep328 on July 21, 2023, 02:53:09 PM
Sorry to hear that. I'll have my people talk to your people and cancel any plans for a get-together.
I'm definitely going to look into improving the brakes and, as I said, it wouldn't bother me to install a different master cylinder but going along with what David said, I owned other Honda 4s of that era and don't recall their brakes ever causing me concern. I'm NOT saying they were up to modern standards but they never scared me. Yesterday this front brake did! Admittedly, today, a bit less so. ;)
Post by: Oddjob on July 21, 2023, 03:25:53 PM
Post by: Rozabikes Tim on July 21, 2023, 03:43:47 PM
no good looking original when the bikes stuck in the side of a car, I'll take stopping every day.
;D
Post by: Multiman on July 21, 2023, 04:19:52 PM
Master cylinder kit DSS
Made a new brake lever bush as the original had completely reverted to rust.
Braided brake lines. Wezmoto
Slave cylinder new gasket etc DSS
Pivot was seized so freed up
EBC pads Wemoto
Its much better but still not up to modern standards
Post by: Bryanj on July 21, 2023, 04:33:47 PM
Braided lines you can buy hose and fittings and make yourself or i can to your measurements at cost.
Master kit only needed if not pumping or releasing
Post by: Mikep328 on July 24, 2023, 12:18:34 PM
Interesting! Will the CBR master fit without any mods to the OEM CB400 switchgear or does different switchgear have to be used?
Post by: Trigger on July 24, 2023, 12:26:35 PM
Post by: Mikep328 on July 24, 2023, 12:56:43 PM
FWIW, my CB400 is going to be my normal rider, not a weekend or "special event" bike. Therefore, as much as I would like to retain the OEM gear/appearance, It's less important than being able to STOP.
Post by: Oddjob on July 24, 2023, 01:18:25 PM
Post by: Trigger on July 24, 2023, 01:19:38 PM
Ah! OK... I'm working/hoping to get adequate performance from the OEM but am wanting alternatives in case I can't get sufficient performance.
FWIW, my CB400 is going to be my normal rider, not a weekend or "special event" bike. Therefore, as much as I would like to retain the OEM gear/appearance, It's less important than being able to STOP.
It all depends on what brake parts are old and worn out. Easy to do a full overhaul with, Stainless steel brake piston, new OEM piston seal, new brake lines and used a DSS aftermarket master cylinder or refurbish your original with a new service kit. You can always have the disc drilled for extra grip ;)
Or if you want a very good braking system, be prepared to spend £££
Post by: Laverdaroo on July 24, 2023, 01:22:40 PM
A CBR 600 master cylinder will be for a double disc and not for a 400/4 single disc. ;)Yup, fits straight on and works fine with no immediate on/off application. No faults found and works perfectly. Really happy with the install and did so after much research from other sites and expertise elseware. Cheap option, dead easy to fit, the lot.
Recommended
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Post by: Trigger on July 24, 2023, 01:24:14 PM
Post by: Laverdaroo on July 24, 2023, 01:24:27 PM
I'm going with the CB1300 MC Mike, it has a mirror mount and a front brake light switch if you ever need to remove the one on the bottom yoke. Look identical to the CBR600 one although I can't see any mirror mount on Roos pic.The Long Haired General wanted bar end mirrors which aren’t in at the min as it’s being fiddled with and sick of catching my pockets on it walking around the shop.
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Post by: Laverdaroo on July 24, 2023, 01:25:42 PM
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Post by: Mikep328 on July 24, 2023, 01:36:35 PM
Post by: Trigger on July 24, 2023, 02:07:00 PM
Roo has forgot to mention that he doesn't have standard handle bar switches and his bike is £££ modified ;)
Post by: robvangulik on July 24, 2023, 03:16:09 PM
On all Honda masters the piston diameter is cast on the outside, most often facing the handlebars.
Post by: Trigger on July 24, 2023, 06:57:40 PM
The CBR600 master is most likely a half inch or 12,7 mm, which is fine for a single 38mm piston caliper.
On all Honda masters the piston diameter is cast on the outside, most often facing the handlebars.
My up to date tech data Honda book only shows the spec for a CBR600 from 1999 and the size is 13.958 to 14.000 mm ;)
Post by: robvangulik on July 24, 2023, 08:52:37 PM
Post by: Laverdaroo on July 25, 2023, 12:52:40 AM
They fit the STANDARD bars that I have on the 400 so a quick fit also. Not the first to do this swap, loads have done it to sort the issue of crap anchors.
The master cylinder is a 93-98 CBR600, if you want the link to the levers let me know.
Happy to help
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Post by: Mikep328 on July 28, 2023, 08:36:29 AM
It seem to me that by design the front brake is only half of a brake. The fixed pad cannot move and it does not touch the brake rotor if properly adjusted. SO...when the front brake is actuated, the piston moves ONE brake pad against one side of the rotor. It is the ONLY brake pad applying pressure to the rotor until your hand applies enough pressure for that pad to warp/bend the rotor far enough to engage the fixed pad. Frankly, this makes no sense to me, the rotor has to literally be bent into contact with the opposing pad before pressure is applied to both sides of the rotor.
Without a floating rotor, I don't see how such a brake can work effectively under any conditions. It seems to me that the only way to get a GOOD front brake is to either have a floating rotor with the current caliper or a replacement dual piston caliper.
Or am I missing something obvious here about the brake construction/operation?
Post by: Bryanj on July 28, 2023, 08:44:51 AM
The "fixed" pad is mounted to the alloy bracket that pivots, or at least it should do, on the steel pin held by 2 small and one big bolt. The 2 small bolts hold an alloy bracket that SHOULD slide off the pin.
So when you aply the brake the piston moves out till pad touches rotor, then further movement brings the other pad to touch as the arm pivots.
If the clearance on "fixed" pad is too much the lever moves a long way, if too little the pad rubs.
The only thing that retracts the piston is the twist in the rubber seal which is why, unless the seal groove is super clean, the brake can drag and a dremel brush WILL NOT clean the groove, it just polishes the crud. You need a dental type pick and patiencs
Post by: K2-K6 on July 28, 2023, 09:31:16 AM
There's less swing calipers around nowadays, but many bike and car use sliding pins to move with pistons on one side only..
Floating disc, these are almost entirely to deal with control of disc expansion through heat range where used to avoid the disc going wavy and not to accommodate caliper geometry.
Post by: Mikep328 on July 28, 2023, 11:42:57 AM
Post by: Oddjob on July 28, 2023, 03:08:22 PM
I am however in disagreement with Bryan regarding cleaning the slot for the seal, a Dremel is ideal for this job, it's what you put on the end of it that matters. The abrasive discs I use will remove alloy, the crud that collects in the slot is hard but it's no match for the discs, I wouldn't use the most abrasive ones though, a 220 one should work to do the heavy work and then go up to 400 and 800 to finish off the slot.
I'm currently restoring a CB550 rotor cover that's been down the road and has some bad gravel rash on it, it's about 80% done and was restored using those discs, I'll post pics of it when finished and I'm sure you'll be surprised just how good these discs are for cleaning alloy, the inside of a caliper body for instance will look new after some light brushing with these discs and they are cheap, you can get around 27 pieces for £8.
https://www.ebay.co.uk/itm/314692515911?hash=item494522b847:g:oUQAAOSwoBRkpjs3&amdata=enc%3AAQAIAAAAwLV96za6Q43eRYqm8FJ6aiJrsd%2BoMDHOxQUCd77uPlqr9YduV6EDM17ZrfMDX6jnnJhylJvKR90AJgHLjPHwrkhs2j%2BKIIjLCKrpYplPDH1a7R5jztAskFfgw%2FTCRL78iyBS2Er3JP7H2oBUbNa90OZ4E8Isk1%2FmIYGOC98SI%2Fp8oUD2u%2BagCp5sDrIYTLYJgPTSNje1fip332tY7CmXh59xmm7dt8l87qnj66y1tpnqAIHIDjOhz2OBK6zbii3Dzg%3D%3D%7Ctkp%3ABk9SR6DyiM2zYg
Post by: robvangulik on July 28, 2023, 04:27:21 PM
It is only one groove per caliper so how much time can you save by doing it mechanically in stead of by hand?
Post by: Oddjob on July 28, 2023, 04:40:59 PM
Post by: Trigger on July 28, 2023, 05:38:06 PM
Post by: robvangulik on July 28, 2023, 06:01:30 PM
Post by: Laverdaroo on July 28, 2023, 06:49:13 PM
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Post by: Mikep328 on July 30, 2023, 09:01:31 AM
I have ordered two sets of pads - a sintered set and an organic set. I don't know what type/brand is in the bike at the moment but they have a different color backing plate to either of the two I have ordered so it's probably different than either of the pads I purchased. I am thinking that if different pads don't improve performance, I am going to purchase a Brembo MC with a 12mm piston and, assuming it makes the huge difference I expect, regretfully adopt the non-OEM look.
Post by: McCabe-Thiele (Ted) on July 30, 2023, 02:14:31 PM
I guess it all depends on expectations - if you ride a modern twin front disc bike you will never be happy with the standard 400 set up.
Post by: Mikep328 on July 30, 2023, 05:05:08 PM
I'll advise if I find any improvement with either of the different pads.
Post by: McCabe-Thiele (Ted) on July 30, 2023, 05:27:14 PM
Post by: Mikep328 on August 02, 2023, 12:32:12 PM
When the fixed pad is adjusted to have the minimum clearance is that spring on the adjusting bolt supposed to push the fixed pad/swingarm back to the established clearance?
This morning I found that even if I adjusted the bolt to provide far too much clearance, so I could move the caliper back/forth maybe 8-9mm by hand, once I applied the brakes and then released the lever, the swingarm/pad did not move back to the 8-9mm clearance. I had to push the caliper inward to re-establish the clearance. Is the spring supposed to be strong enough to do that? It doesn't seem to be very strong - easy to compress with my fingers.
Further... I pulled the caliper bolts to determine the type of pads. They appear to be sintered pads. No idea of the brand but "JB CR FF" is stamped on the backing plate. Don't know what that means. The pads are quite thick so appear to have very little mileage/use but there are grooves worn into the pads though the rotor is perfectly smooth.
Post by: Bryanj on August 02, 2023, 02:27:35 PM
Post by: McCabe-Thiele (Ted) on August 02, 2023, 02:37:08 PM
Post by: Mikep328 on August 02, 2023, 03:14:29 PM
I checked and the pivot pin/swing arm is very free/moves with no effort at all if the adjusting bolt is loosened to provide some clearance and I physically push the caliper in which forces the active pad back into the caliper and creates the clearance. But it won't return to that clearance on its own once the brakes are applied/released. The spring cannot force the active pad back into the caliper to "open up" the clearance. I suppose it doesn't really matter - it's common for disc brake pads to JUST touch the rotor even when the brakes are not applied but if the 400's pads are supposed to stay in light contact with the rotor, what's the point of the spring?
Post by: Oddjob on August 02, 2023, 03:22:14 PM
If you remove the caliper and test the arm you'll find the spring is plenty strong enough to push any movement to the left back again, maybe test that and see if the spring has lost it's tension or maybe it's the wrong spring.
Post by: Mikep328 on August 02, 2023, 03:40:02 PM
Post by: Oddjob on August 02, 2023, 03:44:11 PM
Stainless steel pistons are available to cure the rusting problem
Post by: Mikep328 on August 02, 2023, 03:57:46 PM
Post by: Bryanj on August 02, 2023, 04:12:28 PM
Post by: Oddjob on August 02, 2023, 04:15:48 PM
Post by: TrickyMicky on August 02, 2023, 04:37:36 PM
Thank You! With the caliper removed (or just loosened), the spring easily moves the arm/pad back on its own. The piston/pad is not noticeably retracting back into the caliper when brake pressure is released. I'm now wondering if a new seal is needed. Sounds like caliper disassembly/inspection would be a good thing.... Just be aware that, as somebody else said, when releasing the brake pressure the only returning movement is the seal regaining its original position, which is negligible. Once the whole ensemble is assembled, and on the bike, the movement of the pad/calliper is barely visible to the naked eye. Can't remember the clearance, it's in the workshop manual which is out on the garage at present, but I'm sure somebody with a better memory than me can help!!
Post by: Nurse Julie on August 02, 2023, 04:40:48 PM
Post by: Mikep328 on August 02, 2023, 04:55:20 PM
Post by: Bryanj on August 02, 2023, 04:58:03 PM
Post by: K2-K6 on August 02, 2023, 05:43:37 PM
This shows the seal is soft and chewy, with enough clear geometry in the groove to operate correctly. If it just moves out only, then the groove at least is not clean.
If you've not got this characteristic on any caliper really, the pads will always rub too much, possibly glaze too.
It's imperative the groove is fully cleaned to produce best operation. Lubricate with silicone grease (it's in the original Honda manuals) that groove and seal to keep it this way as long as possible. This largely stops water (road salt etc) getting into there and causing galvanic corrosion again, it is the only real weather sealing strategy of many caliper with single seal and no boot to protect them from water.
Post by: Mikep328 on August 03, 2023, 07:54:39 AM
I was going to start disassembling the brake system today but decided to wait until all the parts get here so the bike isn't "out of service" any longer than it has to be.
Post by: K2-K6 on August 03, 2023, 08:28:29 AM
Crude but effective, squeeze it with both hands as far as it'll possibly go a few times, until it feels like everything is bending, really severe :o then hold a hand behind the twist grip and hit the ball end of the lever in multiple times to pulse the whole system in a controlled violence :)
During this the lever should repeatedly give the same travel, neither lengthening or pumping outward. All the seals working properly should give absolute consistency under this routine. Any real variables and you'd have to examine why that's the case.
Sounds severe, but properly puts far more elevated pressure through it than any normal use, and always verifying if there's any likely problem.
Final check, after that, roll the wheel to assess release, it should not bind at all after the above. Then ride it to see what ya got.
I do this with every front brake I work on.
Post by: taysidedragon on August 03, 2023, 11:07:23 AM
I do a final check with any hand mastercylinder when it's all set up.
Crude but effective, squeeze it with both hands as far as it'll possibly go a few times, until it feels like everything is bending, really severe :o then hold a hand behind the twist grip and hit the ball end of the lever in multiple times to pulse the whole system in a controlled violence :)
During this the lever should repeatedly give the same travel, neither lengthening or pumping outward. All the seals working properly should give absolute consistency under this routine. Any real variables and you'd have to examine why that's the case.
Sounds severe, but properly puts far more elevated pressure through it than any normal use, and always verifying if there's any likely problem.
Final check, after that, roll the wheel to assess release, it should not bind at all after the above. Then ride it to see what ya got.
I do this with every front brake I work on.
Sounds like recipe for breaking levers!
Post by: K2-K6 on August 03, 2023, 11:45:09 AM
"Sounds like recipe for breaking levers!"
And when would be a good time to find out if there's a failure point in a brake system ?
I'm reasonably confident that any lever I could get to fail with my hands alone I'd not want to be riding with :)
I work on many MTB hydraulic system too, would never want someone else to ride something I couldn't place absolute confidence in.
In all honesty I've never broken one like this. Leaking banjo, bleed closure etc detected that had given owners previous problems but couldn't be found by someone else working on them.
Post by: McCabe-Thiele (Ted) on August 03, 2023, 12:03:51 PM
Post by: K2-K6 on August 03, 2023, 12:24:34 PM
If you are using a nice soft rubber headed mallet that should not break the lever - I guess it depends how hard you strike the ball end.
Oops Ted, thanks as I now realise I didn't put critically the hit method :-[ just the palm of my hand to pulse the lever, no tools or weight required.
There, does that seem better ;D
Post by: McCabe-Thiele (Ted) on August 03, 2023, 01:23:26 PM
If you are using a nice soft rubber headed mallet that should not break the lever - I guess it depends how hard you strike the ball end.
Oops Ted, thanks as I now realise I didn't put critically the hit method :-[ just the palm of my hand to pulse the lever, no tools or weight required.
There, does that seem better ;D
If I used the Palm of my Hand like that I would have a massive red bruise for weeks! :'( :'( :'(
Post by: taysidedragon on August 03, 2023, 06:03:01 PM
If you are using a nice soft rubber headed mallet that should not break the lever - I guess it depends how hard you strike the ball end.
Oops Ted, thanks as I now realise I didn't put critically the hit method :-[ just the palm of my hand to pulse the lever, no tools or weight required.
There, does that seem better ;D
Better. 🙂
Post by: taysidedragon on August 03, 2023, 06:04:17 PM
Post by: Oddjob on August 03, 2023, 06:25:47 PM
Post by: Mikep328 on August 05, 2023, 11:41:34 AM
The 'old' brake fluid that I drained from the system looked like it had just come out of the container! The caliper looked good and had a new-looking SS piston. The groove for the seal did have some grunge in it so I cleaned that up. I installed a new seal, a new Honda brand piston (totally unnecessary - should have disassembled the caliper first before ordering parts) - and the new Vesrah pads. Then installed the new HEL lines/bled the brakes got a good, firm lever...just like it had before! ;) It is raining so I didn't have the opportunity to test the brakes though I ran the bike bike/forth in the community garage. In that minimal bit of testing I couldn't feel any difference at all. :( If the weather is better tomorrow I'll go out and put some miles/braking on the new pads. If there is no improvement, I'll install the Brembo carbon/ceramic pads and see how they work.
The one positive outcome is that the brake is releasing properly now; it appears that was the only thing I accomplished!
Post by: Oddjob on August 05, 2023, 03:14:31 PM
Clean the brake disc off with brake cleaner to remove any existing pad transfer material, a gentle rub with some fine wet and dry won't hurt either. Then take the bike out and do 15 gentle brakes from 30mph and then a 2 mile cool down followed by another 15 or so from around 45mph using moderate brake pressure followed by another 2 mile cool down run, then stop to see how the discs look. You should clearly see some pad transfer, it's a sort of blue/grey mist on the surface of the disc, then do 15-20 full on braking sessions from around 65-75mph, dropping the speed down really quickly but rolling off when around 10mph and then back up to speed later, followed by a 5 mile cool down run.
I've copied and pasted and adapted that from a post of mine on another forum, the method was advised by SBS on how to bed in ceramic pads but can also be used for other materials
Post by: Mikep328 on August 05, 2023, 04:41:22 PM
Post by: K2-K6 on August 06, 2023, 07:13:43 AM
Ordinarily, you'll feel them improving as you go through running and preparation to then give assessment.
Post by: K2-K6 on August 06, 2023, 08:23:31 AM
The older systems I feel that you'll definitely feel the difference as the pads and discs get a little more familiar with each other :)
Most disc aren't good immediately after initial cleaning with solvent, whatever their design and material spec.
Post by: McCabe-Thiele (Ted) on August 06, 2023, 10:57:25 AM
Then again back then a new car had to be run in for the first 500 miles or so.
Post by: K2-K6 on August 06, 2023, 11:20:10 AM
Interestingly back in the 1960's my late father would always advise car owners not only to bed in new brakes but tyres as well.
Then again back then a new car had to be run in for the first 500 miles or so.
Drum brakes (extensive in that era) are significantly subjected to circular irregularities in surface of friction materials and shoe pivot point variables. Getting them all worn so they touch competently of good advice certainly.
Anyone hold the rear brake on while torquing the wheel spindle during wheel installation ? At least takes out any available variables in brake plate position to help as best possible the alignment on them.
Moto-X drum brakes of past era's are usually a bit wide toleranced when it comes to brake plate on spindoe location. Especially with twin lead design, often significantly improved by this tightening method to get both shoe working to maximum effect.
Post by: taysidedragon on August 06, 2023, 11:24:34 AM
Interestingly back in the 1960's my late father would always advise car owners not only to bed in new brakes but tyres as well.
Then again back then a new car had to be run in for the first 500 miles or so.
Drum brakes (extensive in that era) are significantly subjected to circular irregularities in surface of friction materials and shoe pivot point variables. Getting them all worn so they touch competently of good advice certainly.
Anyone hold the rear brake on while torquing the wheel spindle during wheel installation ? At least takes out any available variables in brake plate position to help as best possible the alignment on them.
Moto-X drum brakes of past era's are usually a bit wide toleranced when it comes to brake plate on spindoe location. Especially with twin lead design, often significantly improved by this tightening method to get both shoe working to maximum effect.
Standard procedure for old Brit bike drum brakes. Does make a difference.👍
Post by: Mikep328 on August 06, 2023, 01:53:33 PM
FANTASTIC! It is orders of magnitude better than previously and stops with authority now where it used to be "scary." Of course, since I changed pads, caliper piston and seal, and brake lines I can't say whether any/all of that contributed or was it just new pads/proper bedding. In any case, I am quite pleased with the brakes and with the help of folks on this site!!
As soon as I got back I let the bike cool a bit and proceeded with the next project - pulling/checking/adjusting the carbs. Pulled them off with no drama at all. I want to have them sorted/back on the bike for a ride on Friday. Hope I don't need any parts other than the various o-Rings. I have those and new carb screws from Nurse Julie.
Post by: Bryanj on August 06, 2023, 01:57:22 PM
Post by: Oddjob on August 06, 2023, 02:34:29 PM
Could you see evidence of the pad transfer on the surface of the disc BTW?
Post by: Mikep328 on August 06, 2023, 02:54:42 PM
Yes...Definitely will be buying a few cans of carb cleaner!!! Ultrasonic would be nice but don't have one and don't want to take the time to send them out.
"What pads were those in the end Mike?"
They were the Vesrah V series.
"Could you see evidence of the pad transfer on the surface of the disc BTW?"
Yes, as described in your earlier post.
I really appreciate your suggestions and that of everyone else on the forum! VERY IMPRESSIVE forum!!!
Post by: K2-K6 on August 07, 2023, 04:08:26 PM
From experience, the seal and how the piston moves freely, with the clean return when released, is the biggest shift in most calipers. All other things being equal, it'll shift most brakes from poor to decent operation at least, the other elements obviously all help, but that free movement is absolutely key to making good use of pads etc.
You can see this often on mot rollers for cars with compromised rear calipers, slight dragging (% illustrated on gauges) pads glazed resulting from this, low service and handbrake effectiveness % all cleared by having the calipers seals cleared and lubricated.
They seem such small differences, but priduce a whole trail of inefficiency within the brakes.
These 400 weren't that bad when new (no not a match for current new system) but stopped decently for example I think it's about 30 ft from 30 mph. Often recollection given nowadays would have you applying the brakes at maximum, then sailing on through a veritable time zone, only then to perform a U turn to come back from next week, and only went out to get a pint of milk ;D
They weren't that bad and, just as demonstrated here, can provide perfectly safe current performance.
Post by: Mikep328 on August 07, 2023, 06:30:58 PM
Post by: davidcumbria on August 08, 2023, 07:28:02 AM
https://www.vintagebikebuilder.com/cb550k-carb-rebuild-demonstration.html
Post by: Mikep328 on August 09, 2023, 03:33:35 PM
On modern vehicles I suspect the brakes are so overly-capable that breaking-in the pads doesn't really matter much. And I admit I have never "broken in" pads before. But I cannot adequately convey the difference between how the brakes functioned when I first rode this bike to how they function now after new pads/break in. A week ago they were scary bad; now I would call them good brakes!! Not "good for an old 1970's motorcycle," GOOD BRAKES period!
I don't think that my installing an OEM Honda piston with new seal, and a set of HEL brake lines is responsible for this improvement. I think the Vesrah pads were a notable improvement over what was in there but, more importantly, I believe the big factor was the break-in procedure that OddJob posted. :)
This, of course, is my new-guy observation based on ONE experience with ONE 1976 CB400. One experience does not count for anything in the statistical world. But I'd suggest that if a CB400 brakes are not very good, after first ensuring the mechanicals are functioning properly/adjusted correctly as per guidance on this site, try a set of Vesrah pads and break them in as per Oddjob's post.
Post by: Johnny4428 on August 10, 2023, 09:35:56 AM
Post by: Oddjob on August 10, 2023, 11:27:23 AM
I'm not 100% sure Mike that the pads are critical to this result, I've used quite a few different compounds on my 1300 and most were giving about the same results. It's also other factors that can come into play, organic pads for instance can fade with heavy usage and tend to produce lots of dust, sintered pads don't fade as badly and produce far less dust (as a rule) but the disc wear goes up appreciably. I've found Ceramic pads to be the best, almost no dust, so no cleaning the front wheel every few weeks, far less disc wear, don't seem to fade at all and best of all they give really good feel. My current setup seems really odd to me at present, it gives so much feedback I keep thinking they can't be stopping that well, whereas before when you pulled the lever the bike reacted so harshly, now I squeeze the lever and the bike just seems to glide to a stop in the same sort of distance. It's so good I keep thinking it can't be right.
I'd love someone to try a set of the Brembo ceramic pads and see what they think after bedding them in correctly, maybe this setup is the breakthrough on braking that the SOHC has been looking for for so long. Or maybe not, we won't know till someone tries.
Got to say the bedding in process is kinda boring, I found a loop of my estate was 1 mile, so I kept looping the estate doing braking stops every few hundred yards, then a full loop or loops trying not to use the brakes only the engine to slow down so I could cool the discs, then start again for the next step. I kept passing the same people, I'm not sure what they made of me going past every few minutes suddenly stopping every few hundred yards for no apparent reason.
Post by: Mikep328 on August 10, 2023, 01:39:12 PM
Post by: McCabe-Thiele (Ted) on August 10, 2023, 02:39:16 PM
Post by: pastitpete on August 28, 2023, 04:50:01 PM
pastitpete
Post by: Mikep328 on October 02, 2023, 12:25:14 PM
The 1977 Cycle World test showed the bike stopped from 60MPH in 135 feet. Now that's not fabulous by current standards but it isn't bad. Interestingly, that is the same stopping distance that Cycle World reported for a 2022 Honda CB1000R.
Frankly, I think the "common knowledge" that these bikes "always" had poor brakes may be internet fiction. Apparently, they had good brakes when they were new...well, as good as a 2022 Honda CB1000R anyway! :)
Post by: Laverda Dave on October 02, 2023, 02:22:22 PM