Poly V-belt installation

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TimH
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Poly V-belt installation

Post by TimH »

Time to change the alternator belt. 42K....( 1st time doing this please bear with me)..get the old one off.......is there any
trick to actually getting the new one over the pulley's?.......new one is extremely tight and I can't seem to get it stretched over both.......old one goes back on seemingly easy enough. I do realize the old is stretched due to use and new one should tighter to begin with, but............does anyone have any suggestions?........am I just not using enough muscle?........ #-o

Thanks!
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TimH
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Re: Poly V-belt installation

Post by TimH »

You know I just found this on a google search.

" Poly V-Belt funny story :((


Here is my Poly V-Belt story, started last WE where i took the occasion of a bad weather forcast (it happen sometime) to start my 60000km inspection on my Y04 R1150GSA.
I did the fuel filter change (i wanted to start with the worth part), this was a pita as usual but finally was ok.
Next step was the alternator belt, first time i changed it on this particular bike. My first thinking was "this will be a story of 30 minutes", 3 days after i do think differently .

In November last year (2007) as i just wanted to be ready with any possible early issue with my belt, i went to the dealer and purchased a brand new belt.
From the S/N of the bike (that i purchased at this dealer) they sold me the following reference : 12.31-7681841-692337 4PK592

Sunday , in my garage after removing my old belt, i wanted to install the new one but: It was far to short ,no way to have it installed.
I then checked the reference of the old belt, guess what, the reference was different to new one, old belt ref is: 11.28-7681841-692637 4PK592

This does not look much different in the ref and this is not much difference in the lenght of the belt, but this was enough to have the new belt not matching the bike pulleys at all.

Monday, dealer is closed, so here we are on tuesday morning at the dealer shop.
Me: Sir, the belt you sold me is not the right one!
Him: There is no other possible reference for your bike than this one i sold you
Me: Yes , except the one i do have here in my hand and that i removed from my bike that i purchased in your shop!
Him: I see but your belt reference in "unknown" to BMW.
Me: But on the belt it is written BMW ref bla bla bla.....so this must be a BMW ref!
Then after a while:
Him: I will ask our wrencher
A couple of minutes later:
Him: Our wrencher says it happened to him already that the belt they should install was to short (despite the fact it was the right ref), he then installed a longer one (with another ref).
Me: I am very happy to know that you know things about issues on your products and that to continue to sell parts without being sure they match the bike. This belt was supposed to be a spare part for the case it would failed in the middle of nowhere, if that would have happened i would still be there on the side of the road!

Me again: I want a new longer belt.
Him: Try this one ref is: 11.28-1341779-692337 4PK611

Went back home (in the evening cause i got a f..... job).
Bring my tools and went in the garage with that new belt. 30 minutes later the engine was running fine with a new belt that is not the same then former one nor the same then BMW says to be the right one! "

This sounds exactly like my experience. What a PITA....Has anyone else had this particular experience.?
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Re: Poly V-belt installation

Post by CycleRob »

TimH, Your bike is right on the changeover year to the more elastic (shorter) belt. If your alternator pulley has a flat face and the pulley looks like a solid drum, then you have the newer system with the overrun clutch built into the top pulley. That requires a different belt and install procedure.


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Re: Poly V-belt installation

Post by rdsmith3 »

I am going to replace mine this summer. A couple of other points

- You need a torque wrench that does 8 Nm, which is a very low torque and below the range of most of your average torque wrenches.

- You will have to check the tension in about 6,000 miles.
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Re: Poly V-belt installation

Post by Boxer »

To tighten that #3 nut you'll need a 13mm box end wrench. A socket/ratchet won't fit in there unless you have the shock off. As you roll on the 8nm torque with the right hand, tighten #3 with your left hand. BINGO! Then give the belt the "twist" test to confirm the tightness and put it all back together.
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Re: Poly V-belt installation

Post by Dr. Strangelove »

Read something recently about a decidedly low tech method of testing for proper fitment. Can't remember where I saw it.

You should be able to twist the belt, at proper tension to <90 degrees; more than that and it's too loose.

This is not meant to replace any better more technical info, but is a quick check

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Re: Poly V-belt installation

Post by Daryl.Stamp »

I'm a little concerned.
I replaced the one on my '02 @ the 24000 mile service.
Purchased the replacment from Beemer Boneyard and just took the old one off & put the new one on w/o adjusting anything. It's been on there for over 12,000 miles now without any indication of problems electrically, but when I removed the cover to position TDC for the valve adjust I noticed that there was a very small amount of rubber dust that appeared to come from the belt material. Didn't think much of it until now.

What's the risk of leaving it as-is for another 12K?

DLS
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Re: Poly V-belt installation

Post by boxermania »

There is a little mystery surrounding the Poly Belt, which prompted me to research the subject and here are the findings:

1) Officially on 7/2003 BMW went from the regular pulley on the alternator to the free wheeling one.

2) Haven't found the official reason for the change, although, in some circles it is believed that the reason was to mprove the durability of the belt from 24K miles to the recomended 36 K miles change interval. (As a side note: The alternator app on the bike is the same as in the automotive world, yet in that open environment, under the hood and with no protection the automotive variant recomended change is 60 K miles and they run beyond that.......go figure what's with the 36 K miles requirement on the bike)

3) There were some bikes sold with the upgrade prior to the 7/2003 update.

4) The way to find out if you have the free wheeling pulley is to look for a triangle on the plastic front cover.

5) The BMW PN is: 12317681841 or Elast 4PK592.

6) The belt adjustment is the same for the regular and freewheeling pulleys....8 nm torque or ~ 6 ft/lb and so on.

7) Apparently BMW has another belt Elast 4PK611 application unknown, at least via my research. (note: the last three numbers indicate the ID of the belt in mm)

Hope this helps.

In closing, I just can't contain my excitment and applaud BMW Motorrad for the vast amount of engineering and technological advance that they have bestowed onto these bikes, we should all be thankful and pay reverence.
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TimH
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Re: Poly V-belt installation

Post by TimH »

Thanks Everyone for your input. I went back to the dealer , got the alternate ref number belt,( the ref number I included above) went back to the house popped it on......all good,......
As far as ajustment goes, wedged a pry bar carefully under the front of the alternator, pushed up, tightend the 13mm top nut and then tightened up the other 2.....verified 90 deg twist and about 1/4 inch deflection on each side when squeezed together
I will say it's kind of a PITA that the parts guy didn't even think to ask for the VIN to check what belt I needed, seemed as though he didn't even know there was an alternate.......Oh Well.........

Thanks Again

Tim :D
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Re: Poly V-belt installation

Post by omg1010 »

Hi everyone,

the belt comes from Continental (a german automotive supplier) and other manufacturers and most spare parts shops on this planet will be able to get it much cheaper than what you pay at your dealer. All what is needed is the ref (4PK611 or 4PK592). Your existing belt should have the ref printed on it so you just need to get the same one. As indicated in an earlier post the last 3 digits indicate the length. Applying a torque wrench in the position as indicated in the manual is near to impossible in my experience. Hence the 90° twist rule is ideal and easy to follow. I have just changed mine and the whole action really is a no-brainer.

If you need a more detailed description please check out this http://www.ibmwr.org/r-tech/oilheads/R1 ... -25-02.pdf

Best regards
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Re: Poly V-belt installation

Post by Boxer »

I believe the changeover occurred 7/2002 on those 2003 models. Mine was mfg in that month, and the parts folks are always selling me the wrong belt. I have to supply the part number every time...which has only been like 3 times.

Rifling through stacks of papers..."Okay where is that part number?"

EDIT: You're right. I just checked RealOEM and the date IS 7/2003. My 7/2002 on my '03 must be what confuses them.
Before 7/2003-12311341779 After 7/2003-12317681841
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Re: ELAST V-belt installation

Post by RGuy »

This is the way I understand the belts....

4PK611 is a traditional polyester v-belt and is installed to a specific 'tension'. It has very little stretch to it. I won't describe the tensioning process... it is well documented.

4PK592 is a ELAST (elastic / stretch type) v-belt and is streeeeetched to a specific 'length'. When installed at the correct length the tension should be correct and should never need retightening. Although it will not be easy, the best method is to install the new belt without moving the pulleys from their original positions.

4PK611 fits models manufactured 07/2003 and earlier.

4PK592 fits models manufactured 07/2003 and later. The pulley is a free wheeling type and is designed to reduce the shock to the belt on engine deceleration not to mention longer life. The pulley has a flat face. There should be a small triangle at the bottom front of the alternator cover to denote the new style belt and pulley.

No I have not installed a ELAST belt yet. I still have about 12,000 miles before that service is due.

Neal
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Re: Poly V-belt installation

Post by CycleRob »

It troubles me when people jam the belts on or off without loosening the 3 alternator mount bolts. :oops: #-o [-X Not only can it damage/weaken the new belt going on, that's understood, but it also ruins the on-bike-spare-belt status of the old belt. In a pinch you could roadside replace a shredded/broken belt with the used old spare belt using a box wrench and repurposing the lug wrench or other tools as a prybar. An hour tops and you're charging again . . . . on your way, with no red dash lite showing. W/O the spare, it's ride it home and maybe kill the battery, park it overnite or later day trailer/truck time.

Image

If you decide you can ride it home on the battery and it's daytime, pull the load relief relay. Junction box cover removed it's the first black rectangular relay on the left in the group of the 4 identical relays. When you pull (and save!) that relay, preferably while it's still running, all the lites and power drains go off. Just the EFI, ignition and starter gets power, minimizing battery drain and prolonging your mileage before the battery is dead. I.D. that relay soon so you'll know how to bail yourself out. That relay cuts off all those unnecessary power drains when you press the starter button.

.
Last edited by CycleRob on Fri May 08, 2009 11:25 pm, edited 1 time in total.
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Re: ELAST V-belt installation

Post by omg1010 »

RGuy wrote: 4PK611 is a traditional polyester v-belt and is installed to a specific 'tension'. It has very little stretch to it. I won't describe the tensioning process... it is well documented.

4PK592 is a ELAST (elastic / stretch type) v-belt and is streeeeetched to a specific 'length'. When installed at the correct length the tension should be correct and should never need retightening. Although it will not be easy, the best method is to install the new belt without moving the pulleys from their original positions.

4PK611 fits models manufactured 07/2003 and earlier.

4PK592 fits models manufactured 07/2003 and later. The pulley is a free wheeling type and is designed to reduce the shock to the belt on engine deceleration not to mention longer life. The pulley has a flat face. There should be a small triangle at the bottom front of the alternator cover to denote the new style belt and pulley.

Neal
Neal, what you say here is incorrect. The last 3 digits just indicate the length of the belt and not the feature "ELAST". You can buy a 4PK611 ELAST as well as a 4PK592 ELAST. Continental says that the 4PK611 (without Elast) is used in Hyundai cars and should not be used in oilheads. The ELAST version is to be used for oilheads only ... However many fellow riders (as well as myself) just use the 4PK611 without ELAST in their oilheads and never had any problems.

Sounds complicated, but the essence is that you can get these 2 belts in both the ELAST as well as the non-ELAST version and that has nothing to do with the last 3 digits.

Kind regards
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Re: Poly V-belt installation

Post by iowabeakster »

I never gave much thought about the belt. You guys have me worried. The actual change of the belt looks simple enough... but the purchase of the correct belt scares hell out of me. [-o<
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Re: Poly V-belt installation

Post by CycleRob »

iowabeakster,

Get a small brown paper bag and breath into/out of it for a full minute.

Take down all the numbers stenciled clearly on the belt's OD. Order or get the new belt using that number.

Replacing the belt is easy. If the whole torque wrench thing isn't possible, use the mid span 90 degree thumb + 2 finger firm twist and a prybar under the alternator (3 bolts just barely loose) to set the tension. Turn the crank pully 1 turn to settle the belt in the grooves. When it's right, fully tighten the 3 bolts and check it again.

This job is a ½ hr tops.

.
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Re: ELAST V-belt installation

Post by RGuy »

omg1010 wrote:
Neal, what you say here is incorrect. The last 3 digits just indicate the length of the belt and not the feature "ELAST". You can buy a 4PK611 ELAST as well as a 4PK592 ELAST. Continental says that the 4PK611 (without Elast) is used in Hyundai cars and should not be used in oilheads. The ELAST version is to be used for oilheads only ... However many fellow riders (as well as myself) just use the 4PK611 without ELAST in their oilheads and never had any problems.

Sounds complicated, but the essence is that you can get these 2 belts in both the ELAST as well as the non-ELAST version and that has nothing to do with the last 3 digits.

Kind regards
Oliver
Thanks Oliver. I did not mean to confuse anyone or imply the 3 digits meant anything other than the uninstalled length. When I said 4PK592 I probably should have said 4PK592 ELAST. I was not aware that Conti made a Poly V version of the 4PK592. If so, it definitely will not stretch like the ELAST will. I was also unaware that Conti made a Elast version of the 4PK611 - thanks for that information. If you buy your belt from your dealer that shouldn't be a problem because they should only have the 4PK611 (poly v) and the 4PK592 ELAST. An auto parts store might be a different story.

FWIW, in many automotive applications the Elast belts are installed with a special tool that works a bit like a shoehorn. It stretches the belt and levers it up and over the lip of the pulley. Here is a picture for those who are bored and/or curious http://www.contitech-ag.net/pages/press ... _uv_dl.jpg
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Re: Poly V-belt installation

Post by omg1010 »

I fully agree with cyclerob. Note the number/ref seen on the old belt and simply buy a new one with that same reference. Mount the new one and be happy about the savings.

By the way the Elast version of that belt appeared only around 2002 and older oilheads always had the non-elast version. And that belt (non-elast) rarely failed hence what was good for your oilhead in former times does not become bad today. On the other hand the belt should last for a good 50 000 km hence you're not goin to change that belt very frequently ....

Best regards
Oliver

P.S. Cyclerob, I followed your instructions to install an oil temp sensor (http://home.mindspring.com/~jabrooks/te ... m#cyclerob). Great stuff, many thanks for your wisdom!
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Re: ELAST V-belt installation

Post by omg1010 »

Thanks Oliver. I did not mean to confuse anyone or imply the 3 digits meant anything other than the uninstalled length. When I said 4PK592 I probably should have said 4PK592 ELAST. I was not aware that Conti made a Poly V version of the 4PK592. If so, it definitely will not stretch like the ELAST will. I was also unaware that Conti made a Elast version of the 4PK611 - thanks for that information. If you buy your belt from your dealer that shouldn't be a problem because they should only have the 4PK611 (poly v) and the 4PK592 ELAST. An auto parts store might be a different story.

FWIW, in many automotive applications the Elast belts are installed with a special tool that works a bit like a shoehorn. It stretches the belt and levers it up and over the lip of the pulley. Here is a picture for those who are bored and/or curious http://www.contitech-ag.net/pages/press ... _uv_dl.jpg
Neal[/quote]

No probs Neal. But the idea is not to buy it from the dealer as the belt will cost you 3 times more for that very same belt.

Kind regards
Oliver
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Re: Poly V-belt installation

Post by R4R&R »

I have a 2004 R1150Ra, purchased in June of 2003. The 'build' date in the plate shows April 2003. The first time I got a replacement belt for mine, the dealer sold me one that was too small. When I took it back they asked me if it was an early or late '04 model. When I told them the date on the bike, they knew which one to sell me. There definitely was a change sometime in that run, and the dealer should be smart enough to ask you!
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