Alternator Belt

[matgriff]

Hi all.  I'm doing a full service on my 2005 1200RT, so I decided to replace the alternator belt.


Looking for the correct replacement I found a confusing number of options, some stating Conti-tech  4PK592, some saying conti-tech 4PK611 with various explanations of lengths, others saying the belt should be Conti-tech Elast type ??


Looking at the one on my bike (I think it's original) it says BMW 12.31-7690 571-692637 4PK582  .... if I enter this into Google it seems to say it's been superseded by the PK592 ??


I'm confused :-(


Mat

[David.]

RealOEM comes up with this 4PK582, http://www.realoem.com/bmw/enUS/part?id ... 1318528385

[David.]

Looking at the one on my bike (I think it's original) it says BMW 12.31-7690 571-692637 4PK582.

Just checked the OEM one off my 2012 TC, same as a 2005 Hexhead and the details are exactly as posted above.

I believe the length is 582mm.



Perhaps this is where the confusion comes from.

[milleplod]

Simple answer.....which is anything but!....is that it depends where you buy your belt, because BMW label Continental belts differently to how Continental label them!
I got this reply direct from Continental when I asked for an explanation -

"The Elast designation on a Contitech belt is to show that it has elastic cord members in the belt, this allows the belt to be fitted by stretching into place without any tensioning device or moveable pulleys. Not all manufacturers, especially OE, clearly show on the belt label if the belt is elastic and this can cause confusion. This is especially important as Traditional and Elast belts cannot be interchanged.

To add to the confusion some manufacturers use the production length as the part number and others use the fitted (stretched) length. Because of this it is important to use the cataloguing system to identify the correct belt and not to use the numbers from the old belt.

The Contitech belt will show for information both production and fitted lengths so the belt that you have will be:

4 [number of ribs] PK [rib profile designation] 592 [fitted length] (582) [production length] ELAST [elastic belt brand name]

I have been told previously by our product managers that BMW always gives the production length for elastic belts while we always give the fitted length as our primary number.

The BMW belt 4PK592 equals our 4PK611 (592) ELAST. Production length in brackets.
The BMW belt 4PK582 equals our 4PK592 (582) ELAST. Production length in brackets

Please also note that in many cases a special tool is required to install the Elast belt correctly without damaging the belt or pulleys.

I hope this helps you to identify the correct belt for your bike."

Easy peasy!
Pete

[matgriff]

Hi Milleplod, thanks again for the help.... I think you've answered every query I've had about this bike so far :-)


So, the correct belt for my bike is the 4PK592(582) Elast....




Great, thanks




Mat

[milleplod]

That's the one! There's a handy little video on YouTube showing how to change the belt - if you've got a large enough spanner, you can easily 'wind' it onto the bottom pulley. https://www.youtube.com/watch?v=YzPTPN98x40 Don't forget to take the main plugs out, it makes it so much easier, and make sure all the ribs of the belt are located inside the 'V' of the top pulley once you've done.
Pete

[David.]

If you've got a large enough spanner, you can easily 'wind' it onto the bottom pulley.

The crankshaft nut is 34mm.

[milleplod]

Yep.....I bought a big adjustable, a used one as it was cheaper! 

WO Norman Maddox, RAF 85 Sqn, will be turning in his grave!  :alas:

Pete

[matgriff]

Hi, yes I have the correct 34mm socket :-)




Thanks




Mat

[B787MECH]

Yep.....I bought a big adjustable, a used one as it was cheaper! 

WO Norman Maddox, RAF 85 Sqn, will be turning in his grave!  :alas:

Pete

I hope it was a Metric adjustable[emoji3]


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[milleplod]

I hope it was a Metric adjustable


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It was indeed!  :))

[David.]

At £13.99 inc. free P&P, this Conti belt is £10.51 less that the same one from BMW, made by Continental.

https://www.motorcyclefasteners.co.uk/p ... es-4pk582/

[simbo]

That's the  one I used when I changed mine,.I kept the old one as a spare on the bike for if it failed whilst away.

[David.]

The original belt on my 2012 Camhead was changed after 3 years and 10,000 miles when the front engine cover was replaced because of corrosion under warranty.
For the cost of the belt, didn't see any point in paying for labour twice as the belt had to come off anyway.

I could always put the old belt back on and be good to go for another 3 years or 14,000 miles! (Service interval being 6 years or 24,000 miles).
Or, is it like tyres, the belt is now 8 years old and past it's sell by date.

[emlevy]

I got stranded when the belt failed on a hired R1150R in the Dolomites about fifteen years ago. The bike had about 38000 miles and I reckon the belt had never been changed. That was a waste of a good riding day.