Alternator Belt - R1150RT

[MarkAZ]

Another newbie question...I'm having problems replacing the alternator belt on my 2004 R1150RT. It has the 50 amp alternator with the freewheeling pulley. I got the old belt (which appears to be in good condition) off, no problem. However the new belt appears to be too short, I can't see how it could fit. It's a ContiTech and has the same numbers printed on it as the old belt, ending in PK592. Doing some research (the most helpful of which is Anton's article) I see that I should have the 'elast' belt, which I believe it is...I got it from Max (part # 12317681841)...and that it takes a $250 tool to tension it to 116mm between the pulleys. OK, I can probably figure out how to get it adjusted to that distance but I can't imagine how anyone could get it on the pulleys in the first place. It seems to be about an inch too short even with the alternator at the bottom of the adjustment range. What am I missing here? Is there a trick to getting it on? Is it supposed to be that short? Can I get it on by putting it over the alternator pulley and cranking it onto the crank pulley? Will it stretch that much? Is there any alternative to taking it to a dealer?

 

EDIT: I measured the outside of the belts. The new one is 600mm, the old is 615. FWIW

[dirtrider]

Morning Mark

 

 

That 592 is belt length.

 

It WILL fit but not easy on some bikes.

 

First put the belt out in the sun for an hour or two.

 

Then put it on the upper pulley & start it on the lower pulley. Then turn the crank pulley bolt & work the belt on the lower pulley as you turn the crankshaft. (Caution: always turn crankshaft in RUNNING direction ONLY)

 

Then tension it best possible to 4.5" (116mm) between the pulley front lips (not between the ribs).

 

DO NOT USE the alternator toothed adjustment system as that will surly strip WELL BEFORE you reach the 4.5".

 

You need to either (carefully) pry the alternator body up with a good smooth ended pry bar or use a pulley pusher between the upper & lower pulley.

 

Again- use extreme caution as you can damage the alternator housing or pinch/crush the wires that run under the alternator (HES pig tail usually runs under the alternator).

 

If it seems too difficult to get to 4.5" just adjust as close as possible then run the bike for a few days/weeks then go back in & tension to 4.5".

 

 

[dirtrider]

Morning Again Mark

 

You can fabricate your own belt tension tool with a little work & some welding.

[Alba]

Hi,

 

Is the set-up on your bike different than this video?

 

[srivera]

Dear MarkAZ:

 

Here is a link to another video from BMW showing how they tension the belt. Although they do not show the replacement, it may help to show how they move the screws and tension it:

 

The tool they use (screw with tension spring) is offered at Max BMW. Here is the link: https://www.maxbmwmotorcycles.com/fiche/PartsDetails.aspx?source=catalog&vid=51765&diagram=ST_12%203%20551

 

I hope this helps.

 

Good luck!

 

 

 

[dirtrider]

Morning srivera

 

That is for the Poly-V belt not the Elastomer belt that Mark has.

 

Trying to use the Poly-V adjustment procedure on the Elastomer belt will most likely strip the alternator adjuster as well as result in low belt tension.

[Alba]

New to R1150RT and a novice when it come to DIY maintenance, I am confused, my video (Chris Harris) does not mention if it is a Poly-V or elastomer construction purely a part number. Srivera video mentions its an elastomer belt but has the technique towards the end demonstrated by Chris Harris.

 

Replacing a 02' belt how do I know if the part number is a poly V or elastomer? And what technique to follow?

 

Thanks

[dirtrider]

clip--

Replacing a 02' belt how do I know if the part number is a poly V or elastomer? And what technique to follow?

 

Afternoon Alba

 

Mainly by part number-- or if you have handled both belts, by looks.

 

ELAST belt P/N 12 31 7 681 841

 

Poly V belt P/N 12 31 1 341 779

 

Most 02 1150RT's (pre 07/03 build) use the older Poly V belt.

 

It gets even more confusing as some later 1150 bikes that have the free-wheeling alternator pulley came with the Poly-V belt as BMW ran short of elastomers during production. So even though those bikes came with the Poly-V they should be replaced with the Elastomer at first belt change.

 

Bottom line is: (IF) the 1150 has a free-wheeling alternator pulley it SHOULD have the Elastomer belt installed THEN USE PULLEY SPACING TO SET BELT TENSION.

 

(IF) the alternator has a standard (non-freewheeling) pulley then it gets the older Poly-V belt & uses the torque on the alternator adjuster to adjust it.

 

[dirtrider]

Future readers___

 

When reading the above-- please keep in mind this thread has split into 2 belt usage questions.

 

One (by OP) is for the later 2004 elastomer belt install

 

& Alba on his 2002 Poly-V install.

 

They are DIFFERENT-- Do Not confuse one with the other.

[srivera]

Morning srivera

 

That is for the Poly-V belt not the Elastomer belt that Mark has.

 

Trying to use the Poly-V adjustment procedure on the Elastomer belt will most likely strip the alternator adjuster as well as result in low belt tension.

 

Ooopsss!!

Sorry for the confusion. Since I have a 2002 R1150RT I was not aware that the 2004 has a different requirement.

Thanks for the heads up!

 

 

[Alba]

clip--

Replacing a 02' belt how do I know if the part number is a poly V or elastomer? And what technique to follow?

 

Afternoon Alba

 

Mainly by part number-- or if you have handled both belts, by looks.

 

ELAST belt P/N 12 31 7 681 841

 

Poly V belt P/N 12 31 1 341 779

 

Most 02 1150RT's (pre 07/03 build) use the older Poly V belt.

 

It gets even more confusing as some later 1150 bikes that have the free-wheeling alternator pulley came with the Poly-V belt as BMW ran short of elastomers during production. So even though those bikes came with the Poly-V they should be replaced with the Elastomer at first belt change.

 

Bottom line is: (IF) the 1150 has a free-wheeling alternator pulley it SHOULD have the Elastomer belt installed THEN USE PULLEY SPACING TO SET BELT TENSION.

 

(IF) the alternator has a standard (non-freewheeling) pulley then it gets the older Poly-V belt & uses the torque on the alternator adjuster to adjust it.

 

Evening at this end of town

 

 

How do I know if I have a free wheeling pulley on my 02?

 

thanks

[dirtrider]

clip--

 

 

How do I know if I have a free wheeling pulley on my 02?

 

 

Evening Alba

 

[Alba]

Thanks DR really good stuff for me to get my head around....

[kioolt]

To add a little more confusion. Not all 04 RT's have the elastomer belt. It just the late 04's.

[dirtrider]

To add a little more confusion. Not all 04 RT's have the elastomer belt. It just the late 04's.

 

Evening kioolt

 

Not all 04's came with the elastomer belt but ALL 04's with the 50 amp alternator should have the elastomer belt installed on them at 1st belt change.

 

See my posting above-- if they have the free-wheeling alternator pulley they take the elastomer belt.

[kioolt]

My 04 did not come with the free wheeling pulley.

[kioolt]

If I can remember correctly, the 04's came out in the early summer of 03 with the dual spark. My 04 was manufactured in I believe May of 03. According to Realoem.com the elastomer belt wasn't used on 04's until 07/2003.

[MarkAZ]

Success!

 

I took DR's advice and left the belt out in the sun (of which we have an abundance in AZ) all day and then was able to easily install it per his advice (that works with tires, too, BTW...I shoulda thought of it sooner). I cut a piece of stiff wire to 116mm to use as a gauge for the pulley spacing. I was able to (carefully) use the tensioner to get it most of the way and then used a couple of wooden wedges under the alternator to lift it the last couple of mm, being careful to avoid any wiring, and tightened the bolts. It only needed to be lifted 4 or 5 mm to get the correct spacing. It all worked out a lot more easily then I anticipated. My Plan B was to fabricate an adjuster per DR's drawing or more likely (I don't have a welder) something like this: Tool

 

Many thanks for the pointers on this. This is a great group and I really appreciate the patience and advice.

 

BTW, here's a great article on the different belts & tools: Alternator Belts

 

Next task: Fuel filter & in-tank hose replacement...

 

 

[MarkAZ]

If I can remember correctly, the 04's came out in the early summer of 03 with the dual spark. My 04 was manufactured in I believe May of 03. According to Realoem.com the elastomer belt wasn't used on 04's until 07/2003.

 

Mine was made in Feb 2004 according to the sticker on the steering head. I guess that makes it a 'late' model.

[d'Maineac]

Quick question: I got a Continental Elast belt from Beemer Boneyard that's intended for the 'later' r1150 (mine's an '05). The old belt is a BMW part with a Conti #PK592. The new one is PK611. Did I get the right one?

[dirtrider]

Quick question: I got a Continental Elast belt from Beemer Boneyard that's intended for the 'later' r1150 (mine's an '05). The old belt is a BMW part with a Conti #PK592. The new one is PK611. Did I get the right one?

 

Afternoon d'Maineac

 

 

ALL 1150Rt's from July 2003 onward that had 50 or 60 amp alternators were factory fitted with the free wheeling alternator pulley. Those bikes should all take the later elsatomer belt.

 

Some of the very early bikes with the freewheeling pulley's were fitted with the Poly-V belts as there was a shortage of elastomer belts (their was a BMW service bulletin to update those to elastomer belts at first belt change out)

 

Your 05 bike should take the 4 PK 592 elastomer belt (4 ribs & 592mm)

 

The 4PK611 is usually a Poly-V belt & for non freewheeling pulley Bikes (before 07/2003)

 

BUT! you should probably call Beemer Boneyard as there are some aftermarket 4PK611 elastomer belts out in the world so maybe they are selling a 4PK611 elastomer for your later build bike.

 

Probably nothing wrong with a slightly longer elastomer belt I just wouldn’t know how adjust that longer (stretchy) belt properly as the BMW elastomer adjustment specs are for the 592mm belts.

 

So verify it ACTUALLY IS an elstomer belt & if so it is probably OK to use-- but THEN see if they have different pulley to pulley adjustment length for the slightly longer belt.

 

[d'Maineac]

Evening, DR

 

Thanks for the response. Yes, it is an Elast belt (per the cardboard and Continental's website), and I do plan on calling Beemer Boneyard about it. In taking the old one off, I noticed the alternator was adjusted to max spacing, and I don't know if this would have any bearing on adjustment of the 611 mm one. I'll see what they have to say about it. Thanks again!

[d'Maineac]

Found more info on the EME website; this is the belt I have:

 

http://www.euromotoelectrics.com/Alternator-Belt-R-Oilhead-Belt-4K592841-p/belt-4pk592841.htm

 

Apparently the length is 592 mm...

[Redman]

Found more info on the EME website; this is the belt I have:

 

http://www.euromotoelectrics.com/Alternator-Belt-R-Oilhead-Belt-4K592841-p/belt-4pk592841.htm

 

Apparently the length is 592 mm...

 

And it is $17.50 ... not $31 for the BMW provided one.

[d'Maineac]

I emailed Mike and he said it is the right one (of course). After looking at the belt again, I noticed (592) after the part number (duh).

[billnboulder]

'04 R1150RT manufactured Nov 2003

 

The original belt was a PolyV belt - that's what I found when I changed it the first time at 36K miles. I bought it from the original owner at 2500 miles so I'm assuming it never had service at a BMW dealership and the opportunity for BMW to replace the PolyV belt with an Elast.

 

After studying this and other forums I bought a Continental 4PK 611 Elast on eBay. In multiple places (including the package for the belt I bought) it indicates a 4PK 611 Elast is 592mm.

 

I threaded the belt over the small pulley (on the alternator) and used a 16mm socket to turn the drive pulley and the belt went on without too much trouble. I cut a piece of scrap copper tubing to 116mm to use as a spacer. I tried using the old alternator tension adjuster to adjust the spacing but the adjuster teeth stripped.

 

I removed the belt, used my copper-tubing spacer to adjust the distance between the pulleys, then threaded the belt over the small pulley and used the 16mm socket to turn the drive pulley while pulling the belt onto the drive pulley. Not easy but it worked. Probably could have done it in 45 minutes if I had done this from the start - likely even less time with a second set of hands. I did not remove any spark plugs - that would have made it a little easier.

 

Given I had successfully used a PolyV belt for 70K miles I wonder if it's worth the effort to use the Elast belt. But I've got a process that works, now, so I'll likely continue using the Elast.

 

Wow, that thing is tight.

[dirtrider]

'04 R1150RT manufactured Nov 2003

 

The original belt was a PolyV belt - that's what I found when I changed it the first time at 36K miles. I bought it from the original owner at 2500 miles so I'm assuming it never had service at a BMW dealership and the opportunity for BMW to replace the PolyV belt with an Elast.

 

After studying this and other forums I bought a Continental 4PK 611 Elast on eBay. In multiple places (including the package for the belt I bought) it indicates a 4PK 611 Elast is 592mm.

 

I threaded the belt over the small pulley (on the alternator) and used a 16mm socket to turn the drive pulley and the belt went on without too much trouble. I cut a piece of scrap copper tubing to 116mm to use as a spacer. I tried using the old alternator tension adjuster to adjust the spacing but the adjuster teeth stripped.

 

I removed the belt, used my copper-tubing spacer to adjust the distance between the pulleys, then threaded the belt over the small pulley and used the 16mm socket to turn the drive pulley while pulling the belt onto the drive pulley. Not easy but it worked. Probably could have done it in 45 minutes if I had done this from the start - likely even less time with a second set of hands. I did not remove any spark plugs - that would have made it a little easier.

 

Given I had successfully used a PolyV belt for 70K miles I wonder if it's worth the effort to use the Elast belt. But I've got a process that works, now, so I'll likely continue using the Elast.

 

Morning Bill

 

Did you get your pulley spacing correct? You stated above 116mm BETWEEN the pulley's? The distance is: 118.5mm between the two pulleys (measured at the ribs). From pulley outer flange to outer flange it's (about) 116mm.

 

The BMW 1150 pulley system isn't as easy to roll the elastomer belt on as on the BMW 1200 hexhead-- try putting the belt out in the hot sun for about an hour next time (it helps but still a pain to roll on)

[billnboulder]

I did space between the flanges, I mis-stated that detail. TY