Rattling alternator pulley?

[Shane J.]

Please look at this video and give me advice. R1150RT, has developed a rattle that is centered on the top pulley. Pulley feels solid, although I haven't pulled off the belt yet. I can't wiggle it. Bearing maybe? New alternator, or is the bearing replaceable? or do you think it is something else?

youtube link to video-

 

[Lowndes]

Shane, It sounds kinda like the alt bearing is kaput.  Hard to tell in a vid. 

 

Do you know how to use a long screwdriver or a wood dowel rod as a stethoscope??  Very simple  but very effective.  Put one end on/near the bearing case or where you thing the noise is coming from (solid, not spinning) and the other end on the little flap of skin in front of your ear canal.  Try it on various parts of the bike like the heads, crankcase, trans, to get an idea of what normal bearings sound like.  That will quickly pinpoint any bearing that's not behaving.

[dirtrider]

Quote

 

Please look at this video and give me advice. R1150RT, has developed a rattle that is centered on the top pulley. Pulley feels solid, although I haven't pulled off the belt yet. I can't wiggle it. Bearing maybe? New alternator, or is the bearing replaceable? or do you think it is something else?

youtube link to video-

 

Morning Shane 

 

As Lowndes says I also can't tell much from the video. 

 

First thing is check all the alternator fasteners to make sure they are all there & tight. If OK there then next  remove the belt, that will allow you spin the alternator pulley by hand to listen for the bearing being noisy or the rotor shaft having a lot of fore/aft or radial movement.

 

Make sure the pulley it tight with no unusual movement in that. 

 

With the belt removed turn it inside out (ribs facing out) then look it over carefully for chunks missing from the ribs or other pieces missing. 

 

Added: the bearings (if it actually is the bearings) are replaceable but you would have to source them yourself as BMW doesn't service the bearings separately. An alternator shop  (auto-electric) shop could probably sell you the bearings, or install them for you, but E-Bay is usually full of good used 1100/1150 alternators  that might be cheaper & easier. Just make sure you get the correct alternator as the 1150 bikes used 2 different alternators. Plus the 1150RT  using 2 belt pulley's, an early (fixed belt pulley) that looks to be what you have & a later free-wheeling (one way drive pulley) that takes the later elastomer (stretchy) belt. 

 

There is a tag on your alternator showing the amps output so that should be matched up plus the pulley difference that I mentioned above. You can transfer your present pulley onto the later free-wheeling (one way drive) alternator but getting the free-wheeling (one way drive) pulley off is not easy without special tools. 

 

Due to the  free-wheeling (one way drive) pulley not being available any longer from BMW a lot of those are removed from E-Bay alternators prior to listing the alternator & sold separately as those pulley's are worth some money. 

 

 

[Shane J.]

Thank you D.R.

The belt on there now is one I had to source at an auto-parts store on a trip in Canada a few years ago. What is the identifier to distinguish the free wheeling pulley that uses the elastic belt versus the standard pulley?

[Shane J.]

Lowndes- Yes I know that technique. Don't really need it to locate this noise. It is very obvious that it is coming from the pulley location. I am pretty sure that it is bearing noise, I guess I was just hoping it was something easier to fix.

[Skywagon]

if your positive it is the alternator, if it were me, I would just take it to an alternator shop and tell them to fix/overhaul.  If it needs bearings, it likely needs other work too.  If it is the pulley, then see DR's advice/experience on Ebay souring the pulley.  Good luck.  Let us know what your find.

[dirtrider]

2 hours ago, Shane J. said:

Thank you D.R.

The belt on there now is one I had to source at an auto-parts store on a trip in Canada a few years ago. What is the identifier to distinguish the free wheeling pulley that uses the elastic belt versus the standard pulley?

Afternoon Shane

 

[Shane J.]

[taylor1]

If you have your alt.pulled, might want to give a little thought about upgrading your V.R.

[Shane J.]

Just an update. Removed the old belt and the alternator pully felt fine. Bought a new belt and installed it. Problem solved, funny noise is gone. The old belt looked ok but was making noise.