K11 Owners Group

dubu650 · Posted: Wed Jul 09, 2008 11:18 am Post subject: Brake Disk Rattle

Since I bought the bike a year ago, I've been searching for the source of an annoying front end rattle whenever I hit bumps/cracks/railroad crossings etc.

After 7000km of no success, I recently discovered that if I lightly apply my front brakes while going over these bumps the rattle goes away???

I similarly noticed that when I back my bike out of the garage, the front disks rattle a fair amount. At first I thought that the clearance between the ABS sensor and ring was insufficient but that was not the case.

1) Is this rattle normal or a sign that the bobbins are too loose?

2) My tire pressures are set at 38psi. Are they too hard and transferring extra vibration into the fork legs?

Thanks in advance for any replies.

Steve
1994 K1100RS

Flying Duck · Posted: Wed Jul 09, 2008 11:31 am Post subject:

Your bobbins are loose and need replacing. Do a search here on "bobbins" for more info.
_________________
93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE

chopper_harris · Posted: Wed Jul 09, 2008 4:06 pm Post subject:

It is acceptable for them to move side-side as you look at the front of the bike.
If there is any perceptible movement around the circumference (side-side as you stand at the side of the bike) you need to check the bobbins carefully for wear.

The bobbins should be sacrificial - they wear out, rather than the rotor or hub.
Once a small amount of wear occurs, the rotors are bashed into the bobbins every time your brake, and the rate of wear climbs dramatically.

The sages state that there are two types of bobbin - sprung and plain. I have used Motorworks here in the UK for ten years, and they only stock one type.

Can one of the elders please comment on bobbin types Wink

_________________
C1 200 (2001)
R100 RS (1990)
NSU Quickly N (1964)
Honda 400/4 F1 (1977)
MotoGuzzi 1000C (1978)
Suzuki TL 1000 R (1999)
Kawasaki KLV1000 (2005)
K12R Sport (2007) - Wifeys

Flying Duck · Posted: Wed Jul 09, 2008 4:11 pm Post subject:

Once they start to rattle it's time to replace them.

34112310086 - Roll Pin
34112310995 - Roll Pin with Snap Ring
_________________
93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE

Flying Duck · Posted: Wed Jul 09, 2008 4:22 pm Post subject:

dubu650 · Posted: Wed Jul 09, 2008 6:44 pm Post subject:

Thanks for the replies. I'll look into replacing them ASAP.

Steve

Off the grid · Posted: Wed Jul 09, 2008 7:58 pm Post subject:

All the info you need to replace them you can find on this forum.

Search "Bobbins"

Good luck.
_________________
Bane of your existence since July 2006
2007 Triumph Tiger ABS. "Sabertooth"
2009 Husqvarna TE610. "The dirty Italian mistress"

RobWheatley · Posted: Wed Jul 09, 2008 8:49 pm Post subject:

Had to do mine recently, read on here that only 4 each side should have the spring washers on, my old ones had them on every one so did the same, no rattle's now.
Easy job, didnt even take the wheel off, hardest bit is removing the old clips.
Rob
_________________
1999 K1100LTIC Smooth and Quiet Smile

Cruise, BFD & HID
1996 K1100RS. dead but not forgotten.

lrome48 · Posted: Wed Jul 09, 2008 10:50 pm Post subject:

Off the grid · Posted: Thu Jul 10, 2008 12:09 am Post subject:

And make sure you rotate the hole that carries the spring bobbin so it does not wear a groove in the rotor or carrier.
_________________
Bane of your existence since July 2006
2007 Triumph Tiger ABS. "Sabertooth"
2009 Husqvarna TE610. "The dirty Italian mistress"

Geoff · Posted: Thu Jul 10, 2008 1:31 pm Post subject:

One of my front rotors had a rattle, which was eliminated by a new pair of brake pads.
_________________
2000 R1100RT
2008 H-D Electra Glide Ultra Classic

abreeze · Posted: Thu Jul 10, 2008 5:16 pm Post subject:

you should pull one(pins) off and check to see if they are still in tolerence. these rotors float a lot.

dubu650 · Posted: Thu Jul 10, 2008 10:25 pm Post subject:

I'm a bit confused. I took a look at all of the bobbins and cannot tell the difference between "spring bobbins" and "regular bobbins".

The only difference I can see is that on each disk, 3 bobbins have holes that are bevelled while the other 9 are not. These 3 are no tighter, or spring loaded, than the rest.

Please explain, or provide a photo if possible, of the "spring". Is it simply a warped spring washer?

Thanks again.

Steve
1994 K1100RS

lrome48 · Posted: Fri Jul 11, 2008 10:51 am Post subject:

rydor · Posted: Fri Jul 11, 2008 5:11 pm Post subject:

Good info here, I'm about to do this as well, just got the parts.