New to CB400 four and new here! Front brake improvement?

[Oddjob]

What pads were those in the end Mike?

Could you see evidence of the pad transfer on the surface of the disc BTW?

[Mikep328]

"Several big aerosols of carb cleaner or better still an ultrasonic cleaning bath"

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!!!

[K2-K6]

Certainly interesting to get a first hand perspective (yours mike) of before and after on a brake that's relatively unfamiliar to you.

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 

They weren't that bad and, just as demonstrated here, can provide perfectly safe current performance.

[Mikep328]

Yes, the brake is perfectly fine now as far as I am concerned. 

[davidcumbria]

Good to hear and as mentioned before no need to settle for there not as good as modern brakes point of view. Reckon I also need to bed my pads in when my rebuild of the rebuild is done. Rd carbs I found this a very good read
https://www.vintagebikebuilder.com/cb550k-carb-rebuild-demonstration.html

[Mikep328]

Thought I'd add a bit more re brakes.  Today, after installing/tweaking the carbs I went out and did carb testing and some more "brake-in" (NPI)...OK, yes, pun intended.  The brakes are now quite good.  They have excellent feel and do not lack power at all.

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.   

[Johnny4428]

Have been following this post with interest as my 550 front brake was pretty poor. Went out yesterday and followed procedure for breaking in. And a very noticeable difference even for pads that had been used, although not a lot of usage. And proof that there was some pad usage during procedure is the dreaded squeaky brakes are back! So next job chamfering pad edge. Happy days! 😊😊

[Oddjob]

It's important that any old pad transfer is removed before starting the bedding in process. It's like when Formula 1 cars lay a bed of rubber on the track, the track grips better.  For pads it appears they work best when the bed is of the same material as the pads. So clean the disc with some brake cleaner and lightly sand with some fine wet and dry. It works for some reason.

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.

[Mikep328]

Yes, I wouldn't make any real claims that the Vesrah pads would be any better than any other pad, just that they were much better than the pads that were in the caliper which were grooved and appears glazed.  I don't understand the grooves since the rotor is perfectly smooth.

[McCabe-Thiele (Ted)]

Grooves in a pad are usually for dispersal of water.

[pastitpete]

I have an engineered right hand fork leg hung up in the shed which has been machined to house a right hand disk conversion to twin disk. can't convince myself that I want to go the the trouble of the extra engineering that would be involved. having said that I had a twin disc front end on my 400/4 back in the 80's and I could do stoppies on that. also had both disks cross drilled which helped.
pastitpete

[Mikep328]

In doing some research for fueling on my 400 (different thread), I found an original road test from Cycle World of a 1977 CB400 four.

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! 

[Laverda Dave]

Prior to buying my first 400/4 I owned a 250 Matchless single with a drum front brake. Braking was scary on the matchbox to say the least, it really was ‘hit & (or) miss’. The disc brake on the 400/4 was a revelation, not in the ‘stoppie’ league but still really good........until it rained and then it was another story! The rain deflector fitted by Honda over the leading edge of the disc itself did nothing to help either and it was only following the development of EBC sintered pads that wet weather braking became acceptable on early disc braked motorcycles. Compared to a bog standard OEM drum brakes (forgetting the fancy Fontana and Robinson racing drum brakes) disc brakes were a league ahead in the 70’s.