Do I need a new front rotor?

amad1972 · August 5th, 2014, 05:11 PM

I just bought my 2001 Ninja 250 a little over a week ago. Love the bike now that I have adjusted the valves, synced the carbs, and replaced the fuel filter. Running great. One thing I'm unsure of is the front brake rotor. The pads look good, but when I am slowing down I feel a fairly significant surging when I get under 5 mph. It is only when I am on the front brake. If I only use the back brake...no surging. Occasionally, riding along at about 20 mph, I feel a little bouncing, but it is difficult to say if that is just a bouncy road or if it is related to this issue (possibly slightly warped wheel). I put the bike on the center stand and had someone hold the front wheel off the ground. I spun it and watched the rotor and the wheel. I couldn't tell by eyeballing that either was warped, but it does turn freely...and then rubs the rotor...and then turns freely...and then rubs, and so on. What are your thoughts? Anyone experience anything like that?

Thanks

M42 · August 5th, 2014, 05:19 PM

I've been told that mild rubbing thing is completely normal. Both of my rotors do it for like a third of the rotor travel. It doesn't seem to slow the wheel at all, just make a whispery metal noise.

Brother Michigan · August 5th, 2014, 05:22 PM

You've got a warped rotor, it happens all the time. You can either deal with it or replace the rotor. If the warp is not severe, there's little to no danger is continuing to use it.

dcj13 · August 5th, 2014, 05:22 PM

Had what you describe happen in several cars over the years: new rotors and pads took care of the problem every time.

If you're into measuring stuff, you can get a dial indicator and a mounting set at harbor freight and measure how bad your disk warpage is.

Finesse · August 5th, 2014, 07:29 PM

What's rubbing? Brake pads against rotor? Happens a lot... Replacing a rotor is really easy. And brakes are such an important part of your bike. Galfer makes a cool scalloped wave rotor for like $145 shipped.

amad1972 · August 5th, 2014, 07:36 PM

Quote:

Originally Posted by Finesse

What's rubbing? Brake pads against rotor? Happens a lot... Replacing a rotor is really easy. And brakes are such an important part of your bike. Galfer makes a cool scalloped wave rotor for like $145 shipped.

Yes. It's the pads rubbing against the rotor. I may just replace the rotor. Have any of you had any luck purchasing a used on off of ebay that says they are "straight"? Might be worth a try for $20 vs. the price of a new one.

amad1972 · August 5th, 2014, 07:38 PM

Also, would you suggest replacing the pads at the same time? The pads have good life left on them, but don't know if the warped disc would affect that. Or would the old pads re-seat themselves to the new rotor?

Finesse · August 5th, 2014, 07:38 PM

I wouldn't do that. You have no guarantee that it'll be better than yours - in fact it may be worse. If you get a new rotor and change the pads when they're worn and keep the rotor clean it'll last a long long time!

jschorr · August 5th, 2014, 09:16 PM

Aaaaaaa OK. I'll be the red neck s.o.b. have you thought about smacking it round with a rubber mallet?

Please note, this will only work if it drags for one half and not the other generally caused by a drop. Not for the ripping caused by heat warping

agentbad · August 6th, 2014, 10:33 AM

What's the mileage and how about a pic of the pads/rotor. When's the last time you changed the brake fluid?

amad1972 · August 6th, 2014, 03:15 PM

Quote:

Originally Posted by agentbad

What's the mileage and how about a pic of the pads/rotor. When's the last time you changed the brake fluid?

Mileage is just under 16,000. Pads look good. Rotor looks good to the naked eye. Don't know when the fluid was changed last, since I just got the bike a couple weeks ago, but the fluid looks clean.

agentbad · August 8th, 2014, 12:44 PM

Measure the thickness of the rotor and compare to the number stamped on the rotor itself which is the minimum thickness. It's probably warped but I would rule out uneven wear from the pad, or the caliper is sticking a bit on one side. Can find a used rotor for fairly cheap compared to new ones which are stupid overpriced.

amad1972 · August 23rd, 2014, 05:57 PM

I ordered a used "straight" rotor off of eBay. I put it on yesterday and the bike stops as smooth as can be with the front brake now. All good!

Skullz · August 23rd, 2014, 06:56 PM

Some times the rotor can build up with material from the pads and create high and low spots acting like a warped rotor, but all is really needed is a good cleaning of the rotor with some wet sandpaper 400 or higher so as not to wear the rotor away but remove the excessive pad material. If after cleaning the rotor you still have pulsating in the brakes then the rotor is warped to the point of needing replacement.

amad1972 · August 23rd, 2014, 10:11 PM

Quote:

Originally Posted by Skullz

Some times the rotor can build up with material from the pads and create high and low spots acting like a warped rotor, but all is really needed is a good cleaning of the rotor with some wet sandpaper 400 or higher so as not to wear the rotor away but remove the excessive pad material. If after cleaning the rotor you still have pulsating in the brakes then the rotor is warped to the point of needing replacement.

Thanks, but it's too late for that. The "new" rotor is already mounted and the old one is in the garbage.

August 5th, 2014, 05:11 PM	#1
amad1972 ninjette.org member Name: Aaron Location: Knoxville Join Date: Jul 2014 Motorcycle(s): 2006 Honda ST1300, 2001 Ninja 250 Posts: 53	Do I need a new front rotor? I just bought my 2001 Ninja 250 a little over a week ago. Love the bike now that I have adjusted the valves, synced the carbs, and replaced the fuel filter. Running great. One thing I'm unsure of is the front brake rotor. The pads look good, but when I am slowing down I feel a fairly significant surging when I get under 5 mph. It is only when I am on the front brake. If I only use the back brake...no surging. Occasionally, riding along at about 20 mph, I feel a little bouncing, but it is difficult to say if that is just a bouncy road or if it is related to this issue (possibly slightly warped wheel). I put the bike on the center stand and had someone hold the front wheel off the ground. I spun it and watched the rotor and the wheel. I couldn't tell by eyeballing that either was warped, but it does turn freely...and then rubs the rotor...and then turns freely...and then rubs, and so on. What are your thoughts? Anyone experience anything like that? Thanks __________________________________________________ Current vehicles: 2001 Ninja 250, 2007 Honda ST1300, 2013 Mustang GT, 1998 Firebird convertible, 2003 Jeep Grand Cherokee

August 5th, 2014, 07:38 PM	#7
amad1972 ninjette.org member Name: Aaron Location: Knoxville Join Date: Jul 2014 Motorcycle(s): 2006 Honda ST1300, 2001 Ninja 250 Posts: 53	Also, would you suggest replacing the pads at the same time? The pads have good life left on them, but don't know if the warped disc would affect that. Or would the old pads re-seat themselves to the new rotor? __________________________________________________ Current vehicles: 2001 Ninja 250, 2007 Honda ST1300, 2013 Mustang GT, 1998 Firebird convertible, 2003 Jeep Grand Cherokee

August 23rd, 2014, 05:57 PM	#13
amad1972 ninjette.org member Name: Aaron Location: Knoxville Join Date: Jul 2014 Motorcycle(s): 2006 Honda ST1300, 2001 Ninja 250 Posts: 53	I ordered a used "straight" rotor off of eBay. I put it on yesterday and the bike stops as smooth as can be with the front brake now. All good! __________________________________________________ Current vehicles: 2001 Ninja 250, 2007 Honda ST1300, 2013 Mustang GT, 1998 Firebird convertible, 2003 Jeep Grand Cherokee

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August 5th, 2014, 05:19 PM	#2
M42 Wrench wench Name: The Stigette Location: DC/MD/VA Join Date: Jun 2014 Motorcycle(s): TWO HUNDRED FORTY EIGHT CUBIC CENTIMETERS (R.I.P.), SIX HUNDRED FORTY FIVE CUBIC CENTIMETERS Posts: 415	I've been told that mild rubbing thing is completely normal. Both of my rotors do it for like a third of the rotor travel. It doesn't seem to slow the wheel at all, just make a whispery metal noise.

August 5th, 2014, 05:22 PM	#3
Brother Michigan ninjette.org sage Name: Aaron Location: Winder, GA Join Date: Jun 2012 Motorcycle(s): 2013 Ninja 300 Posts: 718	You've got a warped rotor, it happens all the time. You can either deal with it or replace the rotor. If the warp is not severe, there's little to no danger is continuing to use it.

August 5th, 2014, 05:22 PM	#4
dcj13 Participant Name: Dave Location: South of Seattle Join Date: Oct 2012 Motorcycle(s): '94 K75 std Posts: Too much. MOTM - Aug '15	Had what you describe happen in several cars over the years: new rotors and pads took care of the problem every time. If you're into measuring stuff, you can get a dial indicator and a mounting set at harbor freight and measure how bad your disk warpage is.

August 5th, 2014, 07:29 PM	#5
Finesse ran when parked Name: Katie Location: DC/MD Join Date: Aug 2013 Motorcycle(s): Freeride 250R, KLX250SF, mopeds Posts: A lot. MOTM - Sep '17, Dec '14	What's rubbing? Brake pads against rotor? Happens a lot... Replacing a rotor is really easy. And brakes are such an important part of your bike. Galfer makes a cool scalloped wave rotor for like $145 shipped.

August 5th, 2014, 09:16 PM	#9
jschorr ninjette.org member Name: todd Location: pittsburgh Join Date: Apr 2014 Motorcycle(s): 1995 ninja 250r Posts: 130	Aaaaaaa OK. I'll be the red neck s.o.b. have you thought about smacking it round with a rubber mallet? Please note, this will only work if it drags for one half and not the other generally caused by a drop. Not for the ripping caused by heat warping

August 6th, 2014, 10:33 AM	#10
agentbad ninjette.org sage Name: bob Location: Earf Join Date: Apr 2013 Motorcycle(s): 2005 Ninja 250, 2006 SV650N Posts: 642	What's the mileage and how about a pic of the pads/rotor. When's the last time you changed the brake fluid?

August 8th, 2014, 12:44 PM	#12
agentbad ninjette.org sage Name: bob Location: Earf Join Date: Apr 2013 Motorcycle(s): 2005 Ninja 250, 2006 SV650N Posts: 642	Measure the thickness of the rotor and compare to the number stamped on the rotor itself which is the minimum thickness. It's probably warped but I would rule out uneven wear from the pad, or the caliper is sticking a bit on one side. Can find a used rotor for fairly cheap compared to new ones which are stupid overpriced.

August 23rd, 2014, 06:56 PM	#14
Skullz ninjette.org guru Name: Ray Location: 48162 Join Date: Aug 2013 Motorcycle(s): 2012 Ninja 250 Posts: 450	Some times the rotor can build up with material from the pads and create high and low spots acting like a warped rotor, but all is really needed is a good cleaning of the rotor with some wet sandpaper 400 or higher so as not to wear the rotor away but remove the excessive pad material. If after cleaning the rotor you still have pulsating in the brakes then the rotor is warped to the point of needing replacement.