Front brake pulsation

[Rand soper]

So, I pulled the trigger last Saturday and bought a beautiful 2010 NT700V! Very happy with it. I ride daily and my old '82 SilverWing was getting a bit long in the tooth (I still own/love my SilverWing). Anyway, riding home from the dealer in the rain 40+ miles was a dream. Loved the power, and especially the stopping power of the brakes. It seems as though in the early days of disk brakes on motorcycles the designers were overly concerned that riders would go over the handlebars or some such if they allowed the brakes any real ability to stop the bike.

So on to my problem(?), issue(?), concern(?) - Starting on Sunday I noticed a slight pulsation in the front brakes as I am coming to a stop. It does not do it if I only press the rear brakes. It doesn't really do it at higher speeds either but as it slows it gets worse. It doesn't feel dangerous and it stops fine but it is annoying. If it were a car the steering wheel would shake a bit when it happened.

I suspect a warped rotor. I have no idea how the PO rode, but he was an older gentleman and he didn't ride much as it only had 7,200 miles on it. It could also be a sticking left caliper as it seems to drag a bit if you lift the front wheel and spin it by hand.

Saturday I plan to remove the left caliper and re-seat the pistons and see if that helps. At least if it turns out to be a warped rotor new ones are available. Try finding a new rotor for an old SilverWing! I have ordered a service manual am I was a brake / front end mechanic in a previous life.

Any suggestions/assistance would be greatly appreciated! This seems like a very helpful forum, like the CX/GL forum is. Maybe its just Honda people?

 

[Phil Tarman]

Rand, just before I got rid of my '83 Silverwing, it started the pulsing thing and I'm pretty sure it was a warped rotor. I've got 111,000 on my NT and the rotors are still fine. Seems funny that a rotor would be warped at that kind of mileage on the NT.

 

[Rand soper]

My thoughts exactly Phil. I suspect (hope) it may actually a caliper that is a bit bound up. It obviously wasn't ridden much and sitting in damp Northwest Oregon can cause problems with brake fluid plus crud that accumulates everywhere. I'm going to flush the brake fluid and re-seat the caliper pistons and hopefully that will solve it. Other wise I will replace the pads and the rotors and then expect to never have a problem ever again ;-)

 

[EODEAN]

Does it have ABS brakes on it? Both my Wing and my NT will pulsate when using the front brake.

 

[Rand soper]

No ABS. I don't feel any sort of pulsation in the brake lever.

 

[Woodaddict]

watch out the OEM tires can have uneven wear pattern making steering head bearings seem loose or need replaced. not a problem with bearings, its the tire causing problems. the pads seem to wear in a reverse type pattern even trapping air and making noise as you lean. better brand tires will mostly take this away, but some minor wear will still happen. just the nature of this bike will radial tires.
if you had a dial indicator you could put on and check. at just over 7,000 and taken care of good, wheel bearings and axle tourque should be good

 

[ARKNT]

If the caliper is sticking it may be dragging and causing overheating of the brake disk, possibly leading to warpage. I would follow through with new fluid, reseat the pistons. A dial caliper will let you know if the disk is warped. If you can't feel it in the brake lever it may be in spec.
Some brake fluid can get real bad (lumpy, chunky) if it is not flushed once in a while. My KLX250 was rough when I got it. It spent it's life out in the weather and not much maintenance.

Brad

 

[Macka]

Mine has been doing it slightly for the past 30,ooo km or so and does not seem to get any worse.
It is slight and only noticeable at low speed, mostly when slowing down for a red light, so I do not intend to do anything about it unless it gets a lot worse.
Now at 58,ooo km the pads are about 1/2 worn so I will replace pads and discs when they are worn out.
If the NT used "floating discs" it would not be noticeable.

Macka

 

[seagrass]

I am going to second what Woodadict has said. If the original Bridgestone BT20 tyre is fitted to the front it is almost certainly cupped and this will be the cause of your problem.

Even if the tyre has been replaced there is still a strong possibility that the new tyre is cupped so please check this out as it may save you some time money and frustration.

If the tyre has "cupping" then as you apply the front brake and the weight is transferred to the front tyre, the cupping creates a slight shuddering which can seem like it is coming from the brakes.

Seagrass

 

[JQL]

My front tyre will need replacing in the next 1,500 miles and it has just started to pulse the front brake on the hill down to my house. This seems to be the norm on the NT as it always seems to do it when the tyre is coming up for replacement.

I had my brakes checked by the dealer when it first started doing it about 5 years ago and they couldn't find any problems. Since then, it only seems to do it when the tyre is coming up for changing.

If your front tyre is getting down the the wear bars look at changing it for a Michelin PR4 (they are the best for grip - even the French Motorcycle Police use them and they're crazy in traffic! ). If you do use the Michelin, a tip from an ex Michelin tyre person is, on the NT, over-inflate by between 1-3 psi though, the more psi over the harsher the ride. I run at 1 psi over on the front and 2 psi on the rear.

If it continues to do it after the first 150 miles on the new tyre (i.e. it's bedded-in), change the brake fluid as your fluid could be getting a bit old...

Oh and servicing the brakes, as you plan to do, is always a good idea.

 

[Rand soper]

Thanks everyone! Its got Bridgestone Battlax tires. The front is nowhere near the wear indicators but there is slight cupping on the left side of the tire. Running our hand from bottom up, it feels like running your hand the wrong way on a snake. As the back tire is getting low and I ride daily in Portland Oregon (lots of wet riding) I will probably change them out here directly. Michelin PR4's all around

 

[Rand soper]

Today in the heavy rain, the pulsation was much less, almost not noticeable. Tomorrow I will re-seat the pistons and my neighbor has a dial indicator so we can check the rotors for trueness. I have seen brake pistons get stuck like this before when the vehicle hasn't been driven for quite a while which is the case with the NT.

At least replacement rotors are available! My SilverWing they are NLA and there are no aftermarket ones available either.

 

[seagrass]

Honda has had many motorcycles called the Silverwing but if your Silverwing is a GL650 or GL500 from the 1980's try www.metalgear.com.au for rotors as they should have them.

Seagrass

 

[Rand soper]

Well, its definitely the right side rotor that's wonky. Even after re-seating the pistons on both calipers and before touching the brakes if you rotate the front tire the right rotor makes light contact with the pads in one spot. Spin spin spin rub, spin spin spin rub.

 

[Rand soper]

So I replaced both front rotors and pads today. Bike stops flawlessly
I also found the reason for the warped rotor. It seems that the anti-rattle clip that holds the trailing end pad tabs on the caliper was put in wonky. It caused the outboard pad to sit crooked and caused to the caliper to stick. Almost zero wear on three of the pads but the right outboard pad was worn very badly. the trailing end of the pad was almost to metal, leading end was much thicker.
Fixed the anti-rattle clip and put it all back together and now no more problems!