K11 Owners Group

gaillarry · Posted: Thu Jun 24, 2010 9:23 pm Post subject: Bobbins

Got a set of 12 bobbins from Moto-bins in the UK, one week for delivery. I'm putting them on my right rotor.

Reading past messages here I see reference to spring bobbins and regular bobbins. Whats the difference between them? I think I got all the same type. The rotor is nice and tight with the new bobbins.
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1997 K1100GT

John Clauss · Posted: Fri Jun 25, 2010 6:41 am Post subject:

Spring bobbins have steel wire springs in them that hold the rotor tight. The plain bobbins are just that, plain.

The rotor should not be "tight" but have some travel, just lose the excessive play.
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1997 K1100LT
1975 R75/6

It will bring you so close to nausea, it will make you sick! - Big Al

Scott_Anderson · Posted: Fri Jun 25, 2010 7:31 am Post subject:

Like John said, the rotors need to be able to "float".

As the brake calipers are bolted solid to the forks, then the rotors need to have some "freedom" to move around with the expansion of heat when you are braking.
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Ride safe.

1995 K1100LT 0302044
2017 FLHTK Ultra Limited
Garmin StreetPilot 2820
Garmin Zumo 550
Garmin Zumo XT
"One who does not ask questions is ashamed to learn" Danish proverb
1997 K1100LT 0302488(R.I.P.)
1997 R1100RT ZC62149(sold)

gaillarry · Posted: Fri Jun 25, 2010 7:36 am Post subject:

I suspect the 12 bobbins I received are not the spring type. So I should remove 3 and replace them with the spring type. What do the spring type look like, I'll reuse the old ones until I get new ones?
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1997 K1100GT

tmarshall57 · Posted: Fri Jun 25, 2010 7:49 am Post subject:

The spring types have a wire ring which fits over the bobbin.

You don't need these with the Motobins bobbins which are made by Grimeca of steel rather than alloy.

I replaced mine a couple of months ago with the Motobins bobbins and noticed that the rotor was quite tight but expect it to loosen very slightly with time.

There are loads of people on here who have done the same. You will see some questions as to whether the Grimeca bobbins being made of steel rather than alloy will result in the accelerated wear of the rotor. Possibly - but I don't think anyone has proven that this is the case.

As far as I am concerned the rattle has gone.
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K1100RS Special Edition 1997
Arctic Silver/Black

gaillarry · Posted: Fri Jun 25, 2010 7:57 am Post subject:

Thanks I'll keep the moto-bin bobbins in place and order another set for the left rotor.
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1997 K1100GT

sdaniel · Posted: Fri Jun 25, 2010 4:03 pm Post subject:

I replaced both sides just last week. The washer is convex which adds pressure. I like them.
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1993 K1100LT

All that is necessary for the triumph of evil is for good men to do nothing.

AUSBRICK · Posted: Wed Jun 30, 2010 5:10 am Post subject:

Over a year since I fitted motobins bobbins, no signs of wear seem to work really well
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92k1100 lt with sidecar. 93K1100 CAFE..86K75C.95 k1100lt