BMWSportTouring BMWST DB
Page 1 of 3 1 2 3 >
Topic Options
#852104 - 09/13/13 01:14 PM Alternator belt issues
Caddis Offline
Member

Registered: 11/08/08
Posts: 617
Loc: Louisville, Colorado
My '04 RT recently developed a loud "chirping" noise, which sounded to me like a belt squeal. I opened the alternator cover enough to take a look to see if it was the alternator belt. Sure enough, it is getting destroyed.

Since I just had this belt replaced in May (by an independent shop that specializes in BMWs), I am concerned about what would cause this to happen so soon. Other than something like incorrect installation or tension, what else might cause this belt to tear apart so soon? For example, is it possible that the alternator bearings are going bad, making it harder for the belt to turn and causing the belt to slip a lot for that reason?

When I start the bike, the battery warning light illuminates properly to start, and then goes out shortly after the engine starts. So I *think* the alternator is actually turning and charging the battery. But the loud squeal/chirp sounds persist until the bike is well warmed up.

Thoughts?
_________________________
2004 R1150RT

Kevin

Top
#852106 - 09/13/13 01:43 PM Re: Alternator belt issues [Re: Caddis]
jfremder Offline
Member

Registered: 09/16/03
Posts: 736
Loc: SE Wisconsin
Originally Posted By: Caddis
My '04 RT recently developed a loud "chirping" noise, which sounded to me like a belt squeal. I opened the alternator cover enough to take a look to see if it was the alternator belt. Sure enough, it is getting destroyed.

Since I just had this belt replaced in May (by an independent shop that specializes in BMWs), I am concerned about what would cause this to happen so soon. Other than something like incorrect installation or tension, what else might cause this belt to tear apart so soon? For example, is it possible that the alternator bearings are going bad, making it harder for the belt to turn and causing the belt to slip a lot for that reason?

When I start the bike, the battery warning light illuminates properly to start, and then goes out shortly after the engine starts. So I *think* the alternator is actually turning and charging the battery. But the loud squeal/chirp sounds persist until the bike is well warmed up.

Thoughts?


Belt is tension set incorrectly?
_________________________
'04 R1150RT­
48/10
AK
'09 IBR
'11 IBR

Top
#852108 - 09/13/13 01:45 PM Re: Alternator belt issues [Re: Caddis]
Dave Parry Offline
Member

Registered: 01/10/10
Posts: 195
Loc: Kent, England
In which way is the belt getting destroyed? ie, one edge, both edges, the running surface where it contacts the pulleys.

Top
#852132 - 09/13/13 04:06 PM Re: Alternator belt issues [Re: Caddis]
Caddis Offline
Member

Registered: 11/08/08
Posts: 617
Loc: Louisville, Colorado
The belt is coming apart on both edges - it is now only about half the width that it should be. I may post a photo when I get a chance.

I called the place where I had it replaced last time, and due to all of the flooding that we have had in the last few days, he was not busy today. So I took the bike in and waited while they took a look.

They said they had never seen this type of failure (on a new belt) before, and looked to see if it was rubbing on anything, and checked to make sure that the alternator was spinning freely. So they don't know why it failed, unless it was just a bad belt somehow. The owner even called the service dept. of one of the local BMW dealers to see if they had seen this. They said only a couple of times - once when the wrong belt size had been used, and one other "mystery" event. The shop verified that it was the correct belt.

So the issue is fixed for now, but it makes me wonder if this might happen again since we don't know what caused it in the first place.


Edited by Caddis (09/13/13 04:08 PM)
_________________________
2004 R1150RT

Kevin

Top
#852138 - 09/13/13 04:31 PM Re: Alternator belt issues [Re: Caddis]
Caddis Offline
Member

Registered: 11/08/08
Posts: 617
Loc: Louisville, Colorado
And here are the pictures...







_________________________
2004 R1150RT

Kevin

Top
#852140 - 09/13/13 04:32 PM Re: Alternator belt issues [Re: Caddis]
Dave Parry Offline
Member

Registered: 01/10/10
Posts: 195
Loc: Kent, England
Manufacturing fault i'd say.
No, having now seen the photo's it definitely looks like it's been rubbing on something sharp!


Edited by Dave Parry (09/13/13 04:34 PM)

Top
#852141 - 09/13/13 04:32 PM Re: Alternator belt issues [Re: Caddis]
dirtrider Offline
The Oracle
Member

Registered: 06/05/10
Posts: 8182
Loc: Ohio
Afternoon Caddis

Your 2004 BMW 1150 uses an elastomer (stretchy) belt not the old Poly-V belt.

So maybe remove your front cover & get the belt numbers to verify it actually IS the correct elastomer belt. Or possibly call the installing dealer & get the EXACT belt number installed.

Assuming the correct elastomer belt installed then possibly the belt was tensioned incorrectly.

Your 2004 1150 tensions that alternator belt by engine to alternator pulley spacing NOT by any sort of belt tension feel or twist. In fact it takes a special BMW pulley spacing tool to verify it is set correctly.

That pulley spacing can be set without the proper tool but you have to know the pulley spacing distance & that info isn't published in any manual that I know of.

So personally I would call the installing shop & have them explain to you (exactly) HOW they set the belt tension. If they have the special BMW (expensive) tool then probably OK. If they say by feel then I would really question the integrity of their work. If they say by pulley spacing then have them give you those numbers & where they were measured at. I have the numbers but won't post them here until they give you the info on how they set yours.
_________________________
D.R. ___
Sent from my rotory dial wall phone!

Top
#852143 - 09/13/13 04:45 PM Re: Alternator belt issues [Re: Caddis]
dirtrider Offline
The Oracle
Member

Registered: 06/05/10
Posts: 8182
Loc: Ohio
Afternoon Caddis

My data here shows that broken belt you show is the OLD 12 31 1 341 779 Poly-V belt. BMW did install a few of those old poly-V 12 31 1 341 779 on the very early 1150's but not on your later 2004 bike.

Even so there was a BMW service bulletin to replace that poly-V with the correct elastomer belt at first belt change.

It looks you might have had the incorrect 12 31 1 341 779 belt on that 2004 1150 bike.

Added: If I were you I would call yours (or another) real BMW certified motorcycle dealer & get the latest & CORRECT belt number for your 2004 bike then see if that is what has been installed on your bike.


Edited by dirtrider (09/13/13 04:48 PM)
_________________________
D.R. ___
Sent from my rotory dial wall phone!

Top
#852159 - 09/13/13 06:00 PM Re: Alternator belt issues [Re: Caddis]
Caddis Offline
Member

Registered: 11/08/08
Posts: 617
Loc: Louisville, Colorado
I called a local BMW dealer and they looked up the part number for me, they said that there are two possible belts:

12 31 1 341 779
and
12 31 7 681 841

and that the second one is for alternators with the "freewheeling" pulley. He didn't seem to know whether this second one was the newer elastomer belt. But from another reference I found online, the part number that ends with 841 is the elastomer belt.

According to the owner of the shop that I used, he did not use the 841 belt because it is too long, and he cannot spread the pulleys apart far enough for it to work properly. I don't know what to say to that. Does that make any sense?

So it appears that my bike had a poly-V belt on it, and the shop simply replaced it with a new poly-V belt. Am I asking for trouble by just leaving it that way?
_________________________
2004 R1150RT

Kevin

Top
#852161 - 09/13/13 06:01 PM Re: Alternator belt issues [Re: dirtrider]
kioolt Offline
Member

Registered: 09/06/01
Posts: 735
Loc: Bel Air, MD USA
Not all 2004 RT's had the newer belt. If I go to buy a belt for my 2004 RT and tell them it's a 2004, I get a belt that there is no way that it can be installed. It is absolutely to short. I started telling them it's a 2003 when I go to buy belts and I haven't had any trouble since. My 04 RT is an early 04 by the way. It might be best to go by the serial number when ordering a belt.


Edited by kioolt (09/13/13 06:02 PM)
_________________________
2004 R1150RT 151,500 miles
1991 K100LT 128,000 miles
1982 R100RT 106,900 miles
Total 386,400 BMW miles
AMA,BMWRA,BMWMOA
The cheapest thing on a BMW is the nut that connects the handlebars to the seat.

Top
#852166 - 09/13/13 06:15 PM Re: Alternator belt issues [Re: Caddis]
Caddis Offline
Member

Registered: 11/08/08
Posts: 617
Loc: Louisville, Colorado
That seems to indicate that the elastomer belt is shorter than the older poly-V belts. Interestingly, the shop I used told me that the belt they put on is the shorter of the two choices, and that the the other one (the elastomer belt) was too long. ??
_________________________
2004 R1150RT

Kevin

Top
#852168 - 09/13/13 06:25 PM Re: Alternator belt issues [Re: Caddis]
dirtrider Offline
The Oracle
Member

Registered: 06/05/10
Posts: 8182
Loc: Ohio
Evening Kevin

The 12 31 1 341 779 is the old poly-V belt. That was for the PRE free-wheeling pulley (pre 7/2003) bikes. That belt was also installed on some early free-wheeling pulley bikes (at original build) as there was a shortage of 12 31 7 681 841 elastomer belts at build time. There was also a BMW service bulletin that explained the issue & said to use the 12 31 7 681 841 belt at replacement time.

The 12 31 1 341 779 actually can be used on the later free-wheeling pulley bikes but it requires a re-tension at 6,000 miles (the elastomer belt doesn't).

One of the big issues I have seen with using the 12 31 1 341 779 poly-V on the later 1150 bikes is the tec tries to pry the belt on while rotating the crank pulley (like the elatomer belt is installed) & that tends to cut the poly-V belt cords so you end up with a belt looking like that one in your picture. They also don't remember to re-tension the belt at 6K as it isn't specified in the maintenance sheets for the later elsastomer belt bikes.

Have your dealer pull up & send you (or at least show you) Service Bulletin 1200104(003) dated March 2004. I can't post or send that bulletin as it is BMW proprietary info & I don't have permission.
_________________________
D.R. ___
Sent from my rotory dial wall phone!

Top
#852171 - 09/13/13 06:32 PM Re: Alternator belt issues [Re: Caddis]
dirtrider Offline
The Oracle
Member

Registered: 06/05/10
Posts: 8182
Loc: Ohio
Originally Posted By: Caddis
That seems to indicate that the elastomer belt is shorter than the older poly-V belts. Interestingly, the shop I used told me that the belt they put on is the shorter of the two choices, and that the the other one (the elastomer belt) was too long. ??


Evening Kevin

The elastomer belt is shorter in static form when held up against the poly-V belt but keep in mind it is stretch (elastomer) belt so it's only tension is through a stretch fit.

The elastomer belt is very small looking when trying to install but those little devils do stretch out & rotate onto the pulley's when rotated on properly. The catch is getting the pulley spacing correct without having the proper (expensive) BMW pulley spacing tool.

The first time you try to install an elastomer belt you will swear it won't fit. After you do a few you find that if you hold your tongue just right & know the magic words they will in fact fit & last a long time (lot longer than the old poly-V did.


Edited by dirtrider (09/13/13 06:45 PM)
_________________________
D.R. ___
Sent from my rotory dial wall phone!

Top
#852175 - 09/13/13 07:05 PM Re: Alternator belt issues [Re: Caddis]
Caddis Offline
Member

Registered: 11/08/08
Posts: 617
Loc: Louisville, Colorado
Thanks DR.

So I guess I will leave the new poly-V belt alone for now, as it should still work properly as long as it is re-tensioned at the appropriate time. I will discuss all of this with the shop owner. He has been pretty good with other things that I had done (or at least, I *thought* he was pretty good!). But he didn't seem to know all the facts this time...
_________________________
2004 R1150RT

Kevin

Top
#852179 - 09/13/13 07:14 PM Re: Alternator belt issues [Re: Caddis]
dirtrider Offline
The Oracle
Member

Registered: 06/05/10
Posts: 8182
Loc: Ohio
Evening Kevin

A lot of independent shops find all types of excuses on how/why that elastomer belt is wrong, or too big, or to small, etc as that elastomer belt is a pain install. Then once installed even more difficult to tension correctly as they don't have the proper pulley spacing tool.

About the only post (7/2003) 1150's that I know the elastomer belt doesn't work on is the ones with 40 amp alternators like some GS's & some S models.
_________________________
D.R. ___
Sent from my rotory dial wall phone!

Top
#852185 - 09/13/13 08:24 PM Re: Alternator belt issues [Re: dirtrider]
kioolt Offline
Member

Registered: 09/06/01
Posts: 735
Loc: Bel Air, MD USA
My 04RT has a build date of 03/2003 so I guess I've been doing right by putting on the old Poly V belt.
_________________________
2004 R1150RT 151,500 miles
1991 K100LT 128,000 miles
1982 R100RT 106,900 miles
Total 386,400 BMW miles
AMA,BMWRA,BMWMOA
The cheapest thing on a BMW is the nut that connects the handlebars to the seat.

Top
#852193 - 09/13/13 10:38 PM Re: Alternator belt issues [Re: kioolt]
waynerd Offline
Member

Registered: 07/09/09
Posts: 134
Loc: Westminster, Colorado
Originally Posted By: kioolt
My 04RT has a build date of 03/2003 so I guess I've been doing right by putting on the old Poly V belt.


Same here...well my build date is 06/2003, but DR was puttin' a scare on me for a bit, as I know I installed a poly belt at the last change. I ran out to the garage to double check my frame tag. Last time I changed the belt, I distinctly recall doing all the extra required research to make sure I had a non-freewheeling pulley. So yes, not all '04's use the elastomer belt.
_________________________
Wayne
"High-Town" Crew
'04 1150 RT
'84 V65 Sabre (crate baby)

Top
#852194 - 09/13/13 10:52 PM Re: Alternator belt issues [Re: Caddis]
Caddis Offline
Member

Registered: 11/08/08
Posts: 617
Loc: Louisville, Colorado
The build date on mine is 04/2004, and Eileen's is 02/2004. So it seems like they are both supposed to use the Elast belt. They both currently have new poly-V belts on them.

If I understood correctly, it would be better to have the Elast belt. They last longer, don't require re-tensioning, and are BMW's recommendation. But the poly-V belt should still be OK as long as the tension was set correctly, and I re-tension it again after 6000 miles.
_________________________
2004 R1150RT

Kevin

Top
#852204 - 09/14/13 04:41 AM Re: Alternator belt issues [Re: Caddis]
Jim Moore Offline
Member

Registered: 12/31/00
Posts: 2433
Loc: Jax, FL
Unfortunately I don't think it's as simple as checking the build date. I can't remembe rall the details, but I seem to remember that BMW started using the new pulleys at one point, but they ran out of them and went back to the old pulleys for awhile, then returned to the new pulleys. There is some way to tellwhich pulley you have. Something to do with a triangle stamped on the pulley itself, I think. Sorry to add to the confusion, but I don't remember the exact details.
_________________________
Jim Moore Jax, FL '99 R1100S '02 R1150GS

Top
#852206 - 09/14/13 05:17 AM Re: Alternator belt issues [Re: Caddis]
Galactic Greyhound Offline
Member

Registered: 10/02/10
Posts: 345
Loc: Scotland, UK
Originally Posted By: Caddis
I called a local BMW dealer and they looked up the part number for me, they said that there are two possible belts:

12 31 1 341 779
and
12 31 7 681 841

and that the second one is for alternators with the "freewheeling" pulley. He didn't seem to know whether this second one was the newer elastomer belt. But from another reference I found online, the part number that ends with 841 is the elastomer belt.

According to the owner of the shop that I used, he did not use the 841 belt because it is too long, and he cannot spread the pulleys apart far enough for it to work properly. I don't know what to say to that. Does that make any sense?

So it appears that my bike had a poly-V belt on it, and the shop simply replaced it with a new poly-V belt. Am I asking for trouble by just leaving it that way?


Here's a foolproof way of getting the correct parts for your bike -

Put the last 7 digits of your VIN into the Serial Number box on the link below and hit Search. This will identify your bike in terms of its Production Date and Build Spec. Go to the required Parts Group Diagram (in this case, Engine Electrics/Alternator). Below the selected diagram is a Parts List table - because you have used the VIN for identification, only the parts appropriate to your bike will be listed in this table - parts not appropriate will not be listed:

http://www.realoem.com/bmw/select.do?kind=M&arch=0
_________________________
Ced.

R1100RT 1996.

Top
#852207 - 09/14/13 05:27 AM Re: Alternator belt issues [Re: Caddis]
Dave Parry Offline
Member

Registered: 01/10/10
Posts: 195
Loc: Kent, England
Judjing by the type of damage I wonder if it's just that it was damaged during installation,levering the belt over the pulleys?

Top
#852210 - 09/14/13 06:12 AM Re: Alternator belt issues [Re: Jim Moore]
dirtrider Offline
The Oracle
Member

Registered: 06/05/10
Posts: 8182
Loc: Ohio
Originally Posted By: Jim Moore
Unfortunately I don't think it's as simple as checking the build date. I can't remembe rall the details, but I seem to remember that BMW started using the new pulleys at one point, but they ran out of them and went back to the old pulleys for awhile, then returned to the new pulleys. There is some way to tellwhich pulley you have. Something to do with a triangle stamped on the pulley itself, I think. Sorry to add to the confusion, but I don't remember the exact details.


Morning Jim

It wasn't a shortage of free-wheeling pulley's (all post 7/2003 1150's with 50 & 60 amp alternators had the free-wheeling pulley's). (40 amp alternators were the outlier here-- that would be the 1100S & GS)

It was a shortage of elastomer belts that drove the OEM installation of the poly-V for a short range of bikes. Those bikes were built in the calendar weeks 28, 29, & 30. Even so, there was a BMW service bulletin to install the elastomer belt at first belt change.

The was also an external identification on the very bottom of the front cover of the elastomer belt bikes in the form of a raised TRIANGLE.

Supposedly the calendar week 28, 29, & 30 outlier bikes have the following identification marks:
--White dot on the top of the front cover / alternator carrier.
--Yellow sticker on top of the front cover / alternator carrier and / or
--Yellow sticker towards the bottom of the front cover

The bulletins goes on to say---If the (poly) belt has to be replaced, then install an ELASTOMER belt. Once an ELAST belt is installed, remove the yellow or white mark from the alternator mount
carrier.
_________________________
D.R. ___
Sent from my rotory dial wall phone!

Top
#852211 - 09/14/13 06:15 AM Re: Alternator belt issues [Re: dirtrider]
dirtrider Offline
The Oracle
Member

Registered: 06/05/10
Posts: 8182
Loc: Ohio
How to identify the free-wheeling pulley--

It looks like this---

_________________________
D.R. ___
Sent from my rotory dial wall phone!

Top
#852230 - 09/14/13 10:10 AM Re: Alternator belt issues [Re: Caddis]
Caddis Offline
Member

Registered: 11/08/08
Posts: 617
Loc: Louisville, Colorado
I found this reference to be quite helpful.
_________________________
2004 R1150RT

Kevin

Top
#852289 - 09/14/13 04:38 PM Re: Alternator belt issues [Re: Caddis]
rich t Offline
Member

Registered: 01/14/11
Posts: 175
Loc: Jacksonville, fl
If you have ribbed pulleys, that belt looks like the results of a ribbed belt that maybe was not aligned correctly on the pulleys. I had a belt go on a car, that was one rib off on one pulley. It lasted a couple of days, then started shredding like in your picture.

Consider that a possibility.
_________________________
99 R1100rt

Top
#852294 - 09/14/13 05:13 PM Re: Alternator belt issues [Re: rich t]
azccj Offline
Member

Registered: 01/25/11
Posts: 217
I have a 04 RT and it does have the freewheel pulley.

I have bought the supposed elastomer belt both from BMW and an aftermarket parts dealer. I can tell you that the one from BMW is different than the one I received from the aftermarket place. The BMW one is more rubber like and slightly more stretchy when I pulled on it be hand, and it doesn't have the visible fibers like the aftermarket one did. For this particular item I would not go aftermarket and besides what BMW wants for the belt and what the aftermarket company wanted was like $5.00 difference. If you set the belt correctly with that tool and your trying to stretch a belt that wasn't really designed to stretch, then I'm going to guess you'll ruin a bearing or two in not too quick a time.
_________________________
Current bikes

2005 K1200LT
2004 R1150RT
2007 Moto Guzzi Norge
2013 Suzuki Burgman 650, Ya it's a scooter but it will do over 100 MPH
1972 Moto Guzzi Eldorado

Top
#876973 - 03/27/14 08:53 PM Re: Alternator belt issues [Re: dirtrider]
Mark James Offline
Newer Member

Registered: 09/06/13
Posts: 15
Loc: WA, USA
Is there any reason that I shouldn't just replace my 1341 779 Contitech belt and tension it to 8 NM or 70 inch lbs?

Top
Page 1 of 3 1 2 3 >