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I recently noticed that I have a vibration type sound emanating from what appears to be my engine area of my 2004, K1200 LT. I initially thought that it might be the relay for my PIAA driving lights, as the noise occurred whenever I activated the on switch and ceased when I turned them off. But i just discovered that it occurs when I apply the front or rear brake (activating the servo) and disappears when I release them. Could this be the alternator or a part of it (bearing) when I apply a load to it ? It seems to go away after I have run the bike for a period of time but, returns when I start the engine after a short respite (refueling). Anyone have this issue in the past? I have a fairly new battery (7 - 9 months).
 

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Both of my Lt's have done that, I would say its a normal occurrence due to the load....
 

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Are you sure you are actually "hearing" a vibration ? It is more likely to be the alternator drive gear train rattle that is common to the engines, moreso when cold and idling with a load applied to the alternator (brake servo is typical). My '05 does it, sounds like crap, don't worry about it. I find the best remedy is to select first gear and ride off into the deep blue yonder, preferebly for a long time rather than a short time.
 

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Yep, my '05 did it, my '09 does it, and another '05 I rode just yesterday did it, too. Any time I turn on aux. lights, or heated seats/grips/gear, it really starts clanking.
 

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2005 K1200LT
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The alternator is direct (throught rubber cusions) driven by the same gear se tthat holds the starter sprag clutch. this is in conatc with he crank gear and that in turn is in contact with the engine output shaft (drives the clutch and the oil/water pump). Lotta gears banging around when lightly loaded. Perfectly normal. here is a view inside a K engine from the RS family.
 

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jzeiler said:
The alternator is direct (throught rubber cusions) driven by the same gear se tthat holds the starter sprag clutch. this is in conatc with he crank gear and that in turn is in contact with the engine output shaft (drives the clutch and the oil/water pump). Lotta gears banging around when lightly loaded. Perfectly normal. here is a view inside a K engine from the RS family.
That's a great photo...gut-shots of the K1200LT seem notoriously hard to find. There's a guy here with a pick of his avatar I'd LOVE to have a high-res copy of.
 

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jzeiler said:
The alternator is direct (throught rubber cusions) driven by the same gear se tthat holds the starter sprag clutch. this is in conatc with he crank gear and that in turn is in contact with the engine output shaft (drives the clutch and the oil/water pump). Lotta gears banging around when lightly loaded. Perfectly normal. here is a view inside a K engine from the RS family.
Also, there are two or three different gears available from BMW to adjust the backlash. These are factory picked to reduce backlash at assembly, not normally used to "tighten up" worn gears.
 

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jzeiler said:
The alternator is direct (throught rubber cusions) driven by the same gear se tthat holds the starter sprag clutch. this is in conatc with he crank gear and that in turn is in contact with the engine output shaft (drives the clutch and the oil/water pump). Lotta gears banging around when lightly loaded. Perfectly normal. here is a view inside a K engine from the RS family.

Thanks Clark Kent! Great pic... :D
 
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