K11 Owners Group

[Grunter]

My K1100LT (1998 SE version) has developed a slight 'judder' when slowing down from shall we say 40mph. It doesn't happen with a light brake application, or if the brake is used aggressively, just when the lever is applied normally, say slowing down when approaching a junction. Otherwise the brakes are well up to what I have always had.

The ABS has been disabled so I think that can be discounted.

The brake fluid is new - less than 2000miles and 3 months ago and the front brake lines are new (same age as the fluid) There are no leaks.

I have had the wheel out and checked the thickness of the discs and they are hardly worn with less than .02 of a mm difference between the swept surface and the very slight wear ridge on the circumference.

The Pads are less than half worn

The steering head bearings are not worn.

The pistons are free to move in or out.

The 'bobbins whilst they 'rattle' if moved sideways, and always have done, there is no radial movement if you try to move the disc around the circumference.

The only difference I can find is there seems to be less sideways movement of the disc rotor on the right hand side of the wheel than the left, and even when the wheel is off the bike this is hardly detectable.

I removed 4 bobbins randomly from either side to check and there is no discernable difference in thickness on any seperate component.

Your thoughts please.
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1997 K1100LT
1994 R1100RS

[Corkboy]

Came across this before on my K100rs. The disks didn't appear warped, but did judder on medium braking.

After a lot of trawling on the net, came across a few articles suggesting that the pads can leave residue on the disc, in certain places, which can cause erratic braking friction and judder. One cause of this is if the brakes are kept on when stopped at the lights etc, especially if hot. Unavoidable really.

The cure was to perform some very hard braking to get the disks good and hot. Obviously do this at your own risk. This can burn off any residue.

I did this in a carpark and it solved the problem.

Possibly worth a try.
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'08 K1200GT
'87 K100RS 0140995 (Gone)
'97 K1100LT 0188024 (Gone)
'08 Transalp 700 (Gone)

[Grunter]

Thanks for that.

I have access to a surface grinder used by a friend who has a engineering workshop where he cleans up slightly warped cylinder heads, rather than use excessive braking, I wonder if this would work?

I don't mean actually to remove a measurable thickness of metal but to provide a slightly roughened surface similar to honing a cylinder bore before replacing piston rings.

In addition a replacement set of brake pads as well for good luck
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1997 K1100LT
1994 R1100RS

[Grunter]

I had the disk surfaces cleaned up on the surface grinder and then did the same to the hardly worn brake pads.

All braking has now been restored to it's normal performance
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1997 K1100LT
1994 R1100RS

[Corkboy]

Glad to hear it.
Some people mistakenly assume the disks are warped, and replace them, which is expensive and unnecessary (DAMHIK )
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'08 K1200GT
'87 K100RS 0140995 (Gone)
'97 K1100LT 0188024 (Gone)
'08 Transalp 700 (Gone)