Alternator belt: what shouldn't happen

throttlemeister · Post by **throttlemeister** » Sun Jan 21, 2007 3:16 pm

While doing large maintenance on my R11S, I was going to replace the alternator belt. The bike has 53,000km on the dial, and the belt only needs replacing by 60,000km but as I am planning a larger trip in May, I figured I might as well get it over with while the bike is apart for the other stuff.

So, after I pulled the cover off, my eyes just about fell out of their sockets seeing what I saw. Mind you, the alternator belt needs to be replaced at 60,000km not because it is nessesarely worn, but to prevend problems if left in place for too long. I was not amused.

This is what I encountered. I made pictures of the old and new side by side, so you can see the difference. Both belts are supposed to be identical and the only difference being one is old.

Here you can clearly see the the new belt is 'somewhat' wider than the old one... Note the numbers on the belt are identical.

Where did the grooves go?

Better shot of some things missing...

Sides of the belt ripped to shreds.

The edge isn't supposed to have any jagged edges...

I don't know what caused this. I don't own the bike that long yet, but it doesn't seem the belt has been mounted correctly, or was mounted with the incorrect tension. Fact remains, the belt should have been but ok and wasn't officially scheduled for replacement in another 7,000km. Looking at it however, I feel lucky that it lasted as long as it did and it would most likely not have lasted untill the scheduled replacement date. Which in turn, would have left me stranded at the side of the road with a drained battery and no clue what would been wrong.

So, next time you have your bike up for maintenance, do a visual check on the alternator belt. It may not be up for scheduled replacement yet, but it doesn't hurt to check and could save you from having to push the bike home from whereever you are.

theseadog · Post by **theseadog** » Sun Jan 21, 2007 5:31 pm

To para-phrase our southern cousins Gijs....... facken ell geezer

That's what I call one shagged out belt, now you know why it's worth checking them every oil change just in case . . . . .

How are the 'tunes suiting you sir ?

Toodle Pip
Paul

gus · Post by **gus** » Sun Jan 21, 2007 5:48 pm

Hi
I changed mine at about 36000 miles and it still looked new,no fraying.I see that you have noticed that your pulleys are slightly out of line.You need to address this before you stick a new belt on.Check that the washer behind the alternator pulley is there.Also make sure it is tensioned correctly.
gus

nab 301 · Post by **nab 301** » Sun Jan 21, 2007 5:53 pm

I have a fault finder in work which I can post up tomorrow although it looks like a severe case of (age related ) fatigue.
If you have time you may find find something here.
http://www.gates.com/europe/brochure.cf ... on_id=5191
Trouble shooting pdf at the bottom of this link.

Nigel B

throttlemeister · Post by **throttlemeister** » Sun Jan 21, 2007 6:51 pm

Paul: EXCELLENT! Love em to bits!

Gus: according to the microfiche, there is no washer behind the pulley, only on top.

Nigel: Thanks. Confirms the symptoms of misaligned pulleys.

Now, how to fix this, I have no idea. Everything seems to be mounted properly as from the factory. Maybe the bigger alternator is slightly different from the standard one used in non-heated grip setups. I guess I will have to see what BMW has to say about this.

bigblackfalco · Post by **bigblackfalco** » Sun Jan 21, 2007 7:27 pm

I had this on my 2001 S. Check the pulleys for sharp edges.
It's not a major thing....it wouldn't hurt to carry a spare belt like I used to.

Changing the belt is only a 10 minute job.Don't bother with the adjustment procedure. Just hook the belt over the top(alternator pulley) and then start it onto the bottom( crank) pulley. Simply turn the crank pulley with a spannah/ allen key to pull the belt all the way onto the pulley.
Job done.
Bailey.

gus · Post by **gus** » Sun Jan 21, 2007 8:50 pm

Hi
In my repair manual it shows the standard alternator with a washer or spacer behind the pulley and one in front with nut.Further on in the maual it shows a uprated alternator without washer behind pulley.Hmmmm!Just wondering why your pulleys are out of line by 3mm as you stated over on the pelican site.I would check to see where the washer/spacer is on yours.Could have being assembled wrong.
gus

throttlemeister · Post by **throttlemeister** » Sun Jan 21, 2007 9:07 pm

I have the uprated alternator, as does every S with heated grips. Obviously I can only see the washer under the nut, untill I remove the alternator from the bike.

gus · Post by **gus** » Sun Jan 21, 2007 9:27 pm

Hi
Happy spannering.

I would check that the fixing of the alternator is correct and what type of alternator you have fitted to the bike.It could have been changed and reasembled wrong.Example being washers fitted wrong side of mounting brackets.
all the best
gus

Me-109 · Post by **Me-109** » Sun Jan 21, 2007 10:49 pm

throttlemeister wrote:I have the uprated alternator, as does every S with heated grips.

You're assuming that the heated grips were factory-fitted, not retro-fitted by a dealer or individual. Mine were fitted much later, though having ABS as standard it gets the larger alternator anyway.

Steptoe · Post by **Steptoe** » Mon Jan 22, 2007 12:00 am

That looks like normal wear, it gradualy disintergrates.

Depending on year of bike, there's two types of top pulley.

Link to belt change procedure
http://www.ukgser.com/forums/showthread.php?t=81897

Pictures of the two types of pulley

throttlemeister · Post by **throttlemeister** » Mon Jan 22, 2007 4:27 am

I have the bottom one, though I have no idea if that is significant or not.

throttlemeister · Post by **throttlemeister** » Mon Jan 22, 2007 4:31 am

Me-109 wrote:
throttlemeister wrote:I have the uprated alternator, as does every S with heated grips.
You're assuming that the heated grips were factory-fitted, not retro-fitted by a dealer or individual. Mine were fitted much later, though having ABS as standard it gets the larger alternator anyway.

Well I also have the larger battery and I am pretty sure the grips came from the factory.

oyster · Post by **oyster** » Tue Jan 23, 2007 7:46 pm

An interesting item that has revealed itself from this thread :http://www.ukgser.com/forums/showthread.php?t=81897. I remember people asking about changing the pulleys when doing the belt. It wae advised to change the pulleys and belt for the later version on very early bikes. So the 'new' R1100S of 1998 onwards had the new system. I think I'll go and check my 'never touched 1999' belt soon.

tripe · Post by **tripe** » Thu Jan 25, 2007 6:28 pm

I have a '99 and alternator belt had similar damage but not to that extreme. Jap and German, who picked it up at the 36k service said you should check it as a matter of course at every service?