Front brake judder

[Trumpet 215]

Ok, my NC750x is not far off the first service. When braking moderately hard, as the speed drops through around 10mph there a definate judder through the bars from the front Disk. Is this due to the wavey bits or is it possibly a warped disk from new ? I noticed it as soon as I picked the bike up. Is it a problem or a feature ? There is no pulsing through the lever, and at higher speeds there's no judder. I will ask the dealer to check in the next week or so when it has its 600 mile service.

Edited May 1, 2017 by Trumpet

[embee 7,288]

Try some brake cleaner on the discs, available in cheap aerosol often from pound shops etc, otherwise motor factors or last resort Halfrauds etc.

These are very useful for such stuff if you have an outlet in your area (one shown in Oldham)  http://www.eurocarparts.com/ecp/p/car-accessories/car-maintenance-accessories/maintenance-fluids-and-greases/maintenance-fluids/?NOR2897333500&&cc5_858. Check the homepage for current discounts available, it changes every few days.

Use with a paper wipe or clean cloth, then a quick rinse with just the cleaner fluid and let dry.

[Rev Ken 6,324]

It shouldn't judder! if it was an older bike I would suggest checking the head bearings, but unless they were badly adjusted when new it is unlikely. Again I'd be surprised if your disc would be contaminated,  but it is possible. However it won't be due to the wavy disc! I suggest you let your dealer sort it out on your 600 mile service.

[Guest Mac750]

Not being rude do you brake hard at the last moment ? ABS cutting in.?

Have you sprayed and cleaned the bike with anything and contaminated the pads. Has the guy doing the PDI contaminated the disc or pads.

I would report it asap to get it checked.

Is the disc cracked ?

Is the calliper loose ?

Is the wheel nut tight?

Put the front brake on and push down on the forks it should not clunk or click. 

But deffo take it back for them to inspect as although it's a single disc set up the brakes are progressive and smooth no juddering. 

 

 

 

[Tex 36,816]

Maybe the 'Saturday Boy' cleaned half the disc with silicone spray?

 

Back when reverse lights were 'dealer fit' extra cost options a mechanic fitted them and left the apprentice to 'secure the wiring, good and tight'.

 

So he taped the wires along the prop shaft..

 

Oh how we laughed.  

 

Mind you, I made my fair share of cock ups too. One absolute belter I will tell you about one day.. Blush!

[Guest Mac750]

1979 December I'm fitting a full exhaust on a Wolsley Six so I can get to work that afternoon, the whole lot needed replacing after numerous bodges to keep me mobile.

Almost finished with two hours left,  I was laid in the snow on my back by the side of the road ( got to get to work later that afternoon) with cold icy water running down my spine from the slush. All I had left to do was secure the pipe to the manifold clamp which is low down at the back between the engine and fire wall. Just two bolts, two nuts and spring washers and a gasket.  

I didn't have enough clearance to see it as I'm laid under the car which is sitting on ramps at the front. Half an hour trying to get this #*"*®π nut to start turning .

Get on you ~*"#¥> .

I was freezing cold and my hands are so numb, I'm trying to thread the nut on my finger end . 🤡

[Tex 36,816]

Awesome!  

[Mikdent 4,070]

7 hours ago, Tex said:

 

 

Mind you, I made my fair share of cock ups too. One absolute belter I will tell you about one day.. Blush!

 

Bollox to that, I might be dead before I hear this one, come on Tex, spill the beans. 

[GerJ 209]

Back to the problem at hand: do you have an NC with DCT? If so, might it be that what you feel is the DCT shifting down? I noticed this on my wife's NC a few days ago.

Edited May 2, 2017 by GerJ

[Trumpet 215]

Ok, thanks All. It's not a DCT, I'm not kicking in the ABS. I felt it as I left the dealers when it was brand new. It has got less with the miles, but its still noticable. There's nothing obvious on the disk surface and I'm reluctant to clean/scrub it as its so new. This is a brand new Bike. Its booked in on the 15th May for its first service, lets see what the Dealer makes of it. In 42 years of riding I've never bothered with Wavy Disks so have no experience of them. Feels like a dodgy disk now from what you have all said.

Edited May 2, 2017 by Trumpet

[Chip 41]

Alan my brakes were exactly the same from new. I now hav 1350 miles on the clock and the judder has gone. I am sure it's just everything bedding in from new. If you look closely at the disc you will see lapping marks going all directions, the juddering or rumbling as I call it seems to be the discs bedding in. I also cleaned the front and rear discs with break cleaner and that helped. My rear was worse than the front but this is super smooth when applying the breaks now.

[bat-kam 110]

Maybe it's the bake pads compound that is causing it? Not that I ever had a bad set of pads apart from the ones that did not want to stop the bike

[embee 7,288]

12 hours ago, Trumpet said:

.... There's nothing obvious on the disk surface and I'm reluctant to clean/scrub it as its so new. ....

It doesn't have to be obvious, if it was you'd have spotted it. Nothing wrong with using brake cleaner on a (nearly) new bike. I always use brake cleaner when fitting new discs or pads to any vehicle. It just removes any unwanted substances, grease/oil/silicone etc.

 

Brakes need "bedding in" like many things, and there are good and bad ways to do it, We need Andy when he's finished fitting a new regurgle restrictor to his Hurley-P to give the low down on brakes.

[Guest Mac750]

Didnt realise it was a brand new bike a bedding in period is to be expected. Also the wavy disc was mentioned, but this to my mind is nothing more than cosmetics, some will say otherwise but in a production bread and butter road going bike it is not doing anything a smooth edged disc would not do under the same parameters. As it is not pulsing the lever as you use it I would think the disc is not warped.  Applying brake cleaner with a clean lint free cloth will not do it any harm at all. The all steel rotors on my MotoGuzzi if camping in a field overnight looked like brown framing implements left over from the 1930s until they got used and the pads scoured them clean.  Let your dealer know when it goes back in for the first service just to be sure, but as Trumpet says it just may need some more miles . 👍

[Guest twiz]

I've had a similar thing on my 750x - now through about 800 miles and it's noticeably better. Been making sure I don't go too easy on the brakes, so have used them fairly full on every now and then - I have a vague memory from somewhere that you shouldn't go too easy on new pads for risk of polishing them, and them therefore not reaching their full stopping potential.... but I'll defer to someone who knows better as I could be talking complete horlicks.

 

The important point was I experienced a similar judder from new and it's going / nearly gone!

[Andy m 23,447]

The wavy disk is nothing to do with it, just a fashion thing, next year they'll be flower shaped, the year after like Saturns rings and after that who knows, brown starfish?

 

It isn't ABS, thats a lot of proper clicking, chuffing and chatter that would stop as the signal went at 7 kph or so. If you want to prove it, knock the ignition off at 20 mph. No power, no ABS. (Does this do bad things to DCT?).

 

This is IMHO mechanical. I'd be checking the bolts that hold the calliper to the bike, then getting it off to look at how the pads sit in any grooves, if any pins are damaged, if there are any ring marks on the pistons, springs in the wrong way round etc. I must say I aren't struck with Honda heal edge callipers. I'd rather put two pins through the pads then assemble to the bike rather than try and hold pads and springs like a hand grenade while trying to get mounting bolts to start. Check the exploded view in the parts book, missing springs can cause this sort of thing as the pads vibrate/ resonate.

 

Bedding in disc brakes is simple. Find a steep hill, stop while going down it, repeat until rain/spit feels no urge to go within half a mm of the disk. All you are doing is getting the record grooves in the disk to match ones in the pad and burning off any grease. Drums are different, you are trying to shape a curve on something banana like that changes when hot. You cycle them in a more controlled way if you can be bothered. Some here may remember brake shoe dressing? A lovely process involving a grinding set up and asbestos dust.

 

Andy

Edited May 3, 2017 by Andy m

[Rocker66 34,366]

I read somewhere the reason it has a wavy disc was because they cut it out of the same piece of metal as the rear one to save costs

[Andy m 23,447]

That is the most sensible reason I've read.

 

Lots of guff about cooling area, which is exactly what a non-racing disk doesn't need, has been spouted in the paper press.

 

Andy

[SteveThackery 3,090]

I realise this has already been discounted, but for what it's worth I'm sure I've felt an ABS-style pulsing vibration occasionally even though I was in the dry.  

 

It didn't bother me and I just ignored it.

[Guest sykospain]

Alan in Oldham:- [ where I'm headed in a fortnight for my UK "summer" hols ],

 

Pop down to that parts shop that's URL'ed in the post above, Oldham Road just before the main M60 'Roxy' roundabout and get a spraycan of that very affordable Brake Cleaner and clean your front disk, which as Andrew in Leeds says is cut from the same lump of special steel that also makes up the rear brake disk.

 

Then your very slow speed judder should go or reduce dramatically.  I had precisely the same effect when I collected my S-DCT in Aug 2015 from Kevin at the magnificent Rochdale Honda dealership.  It's the brake disk pads bedding in from brand spanking new.  Remember the PDI road-test consists of just 2 trips round their roundabout junction with Rochdale Road and Middledton Road.  So there's no chance for the brakes to bed in there, ¿ is there ?

Edited May 5, 2017 by sykospain

[Graham NZ 1,186]

Bedding-in new pads and discs can be done in two ways; brake hard enough to get the disc/s really hot; brake as you would normally when commuting, avoiding being too gentle and too aggressive.  I've used both methods and favour the commuting method.  Two warped discs on my Buell were caused by the aggressive method.  New pads usually give advice about bedding-in, so wise to follow that.

[Trumpet 215]

Yea but 500 miles is excessive if you all think the pads need that  to bed in. Ive cleaned the disk with brake cleaner, Ive wiped the surface of the pads with it. There is no sign of pad pick up on the rotor. (They looked fine) There's still a shudder from the front forks as the Bike passes through 10mph though. Its not exessive, but I am a perfectionist. I know how to bed in new pads. And I've done it. They are not burned or glazed over. They look fine. I can't help thinking that the wavy disk must have a change in friction under constant braking becasue the pads see less disk then more as they traverse over the gaps in the waves, and at that critical speed there is some sort of resonance through the forks briefly. There is no pulsing through the lever, but braking from high speed does not feel perfectly smooth. It's at the Dealers next monday so hopefully there will be a resolution.

Edited May 10, 2017 by Trumpet

[Trumpet 215]

And the Dealer verdict is .. "They all do that to a certain extent from new. It will get better with time. It's a combination of the edges of the wavy disks and the edge of the pads, They will wear into each other. it sometimes helps to chamfer the edge of the leading edge of the pad. It is better after the brake fluid and disk clean, so kudos to those that said it would help, and it improves with mileage. 

Edited May 15, 2017 by Trumpet

[Guest Mac750]

On 2017-5-10 at 12:17, Trumpet said:

Yea but 500 miles is excessive if you all think the pads need that  to bed in. Ive cleaned the disk with brake cleaner, Ive wiped the surface of the pads with it. There is no sign of pad pick up on the rotor. (They looked fine) There's still a shudder from the front forks as the Bike passes through 10mph though. Its not exessive, but I am a perfectionist. I know how to bed in new pads. And I've done it. They are not burned or glazed over. They look fine. I can't help thinking that the wavy disk must have a change in friction under constant braking because the pads see less disk then more as they traverse over the gaps in the waves, and at that critical speed there is some sort of resonance through the forks briefly. There is no pulsing through the lever, but braking from high speed does not feel perfectly smooth. It's at the Dealers next monday so hopefully there will be a resolution.

 

My bike has done 2,600 miles now. The front brake feels smooth no judder. It did have a little noise as the pads gripped at first but that has also gone. I have not gone out side to look as it's howling a gale, but do the pads actually cover the whole disc area including the wavey edge.

Looking at the photos on line it looks like the wavey edge section in not discoloured which would suggest it is little more than a cosmetic styling ploy,  laser / plasma cutting can now do many things cheaply. So I dont think the wavey disc section is the culprit.

Ask the dealer to check the tightness of  the fork clamps and the head races. In fact the whole front end. Calliper, wheels fender , triple tree bolts etc. The braking on my bike is smooth and progressive. 

I did activate the ABS when a driver came out of a junction . The ABS pulsed quickly but it was obviously kicking in . From your discription it doesn't sound like ABS. 

[Guest Bob]

I sometimes get this judder. Had it on almost all my bikes and normally after a disc/pad change. I now bed brakes in with a few hard stops from speed which seems to work better. It's basically the uneven material transfer mentioned and explained much better than i can here

 

http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths

 

Even after good bedding in it can still happen. I normally get it again after a wet ride. My theory is that the water trapped between the pad and disc helps transfer more pad material. Just a guess though. A clean and, if required, a quick rub over with some oxide paper normally sorts it.