1100 alternator belt?

[MattW]

I have some trips planned over the next few months on my '94 1100 and I've been going over the bike checking stuff and compiling a small stock of spares to take with me.

One of the things which is of unknown age is the alternator belt - the bike had a full BMW service history when I bought it 18 months ago at 34,000 miles but I don't know if it will have been changed yet. Unfortunately it has daft engine bars fitted which make removal of the front cover a pain but after undoing the cover screws, prising it away as far as possible and peering with a torch I can see the belt and it looks in good condition - all crisp, unfrayed and uncracked with the manufacturers lettering clearly visible. So I think I'll just get a belt and take it with me as a spare (at least on my first outing next week).

My only concern is that I believe very early 1100's (and they don't come any earlier than mine) might have been fitted with some sort of weird belt which uses special pulleys and is a dealer only job?

So a quick question for them 'as knows:

The belt looks to be a 'normal' 4 groove car type belt and the end of the part number I can read on the belt says "4 K 611" does this mean it's not one of these 'specials' and I can just go to a motorfactor and buy a 4 groove 611mm belt? (or perhaps 610mm I'd guess 611 is probably non standard).

ta
Matt

 

[Gundog]

Matt....just take an old pair of Pams tights

If needs must, we'll fix it with them....









Oh, and a big hammer..

 

[MattW]

Matt....just take an old pair of Pams tights

If needs must, we'll fix it with them....


Oh, and a big hammer..

But what'll I wear under my trousers then?

 

[sproggy]

The belt looks to be a 'normal' 4 groove car type belt and the end of the part number I can read on the belt says "4 K 611" does this mean it's not one of these 'specials' and I can just go to a motorfactor and buy a 4 groove 611mm belt? (or perhaps 610mm I'd guess 611 is probably non standard).

611mm is the standard size for most oilheads - the other one is a bit shorter at 595mm.

£13 from Motorworks, probably a bit too short to be available in most motor factors, I'd guess - car ones tend to be longer.

 

[motobiker]

I always find questions like this really odd.

My attitude is if in doubt. change it BEFORE you leave.

I can't think of anything more tedious than to be changing parts at the side of the road that could so easily have been done at home. If you feel that you 'might' be needing some new part at some stage.. then fit the bloody thing BEFORE you go.

My bikes all ready for my trip in june.. just an oil change and away I go. No need to weigh myself down with spare parts.. the bikes had new ones fitted over the past 2 services - in preparation. No need to carry a shed load of tools.. the bike will be fully serviced up.

If I was going further east than the Black sea.. or crossing the Gibralter Straits then I might think differently.. But for a bimble round Europe.. I'm not so paranoid.

It almost seems that breaking down and performing surgery at the roadside somewhere obscure is a 'must do' rite of passage. And if the trip report doesn't have some photos of the bike in bits.. well what sort of trip was that??

it does make me giggle.

 

[MattW]

I always find questions like this really odd.

My attitude is if in doubt. change it BEFORE you leave.

I can't think of anything more tedious than to be changing parts at the side of the road that could so easily have been done at home. If you feel that you 'might' be needing some new part at some stage.. then fit the bloody thing BEFORE you go.

My bikes all ready for my trip in june.. just an oil change and away I go. No need to weigh myself down with spare parts.. the bikes had new ones fitted over the past 2 services - in preparation. No need to carry a shed load of tools.. the bike will be fully serviced up.

If I was going further east than the Black sea.. or crossing the Gibralter Straits then I might think differently.. But for a bimble round Europe.. I'm not so paranoid.

It almost seems that breaking down and performing surgery at the roadside somewhere obscure is a 'must do' rite of passage. And if the trip report doesn't have some photos of the bike in bits.. well what sort of trip was that??

it does make me giggle.

Giggle away.

My question was quite simple - given what I could see (and described) is my belt a 'normal' 4 groove 611mm item or the 'special' type which was sometimes fitted to bikes of my age?

So I can buy the right type (and fit the 'bloody thing' whenever I 'bloody well' choose). I don't have doubts about the belt that's fitted but as I don't know its age, I'll change it next time I have the bike in bits. Until then, I'll stick it in my pannier 'just in case' and if the worst happens I (or the nice AA man) can change it.

 

[Stewart H]

The one on mine looked good, but as there was another in the service kit I decided to fit it, all of the fastenings were very dry and stuck, I was glad to have all of my tools at hand to swap that over, now its all freed off I could replace the belt at the roadside with the tools I carry, I carry my old belt on long trips, I know that fits.

Stewart

 

[Welshman]

Giggle away.

My question was quite simple - given what I could see (and described) is my belt a 'normal' 4 groove 611mm item or the 'special' type which was sometimes fitted to bikes of my age?

So I can buy the right type (and fit the 'bloody thing' whenever I 'bloody well' choose). I don't have doubts about the belt that's fitted but as I don't know its age, I'll change it next time I have the bike in bits. Until then, I'll stick it in my pannier 'just in case' and if the worst happens I (or the nice AA man) can change it.

My 99 1150 takes a 611, I fitted a new one and will keep the old one as a get me home..

 

[Vern]

I was changing mine many moons ago,and thought it looked alright,so left it on and chucked the spare in my tank bag.That was 140000 odd miles ago and it must still be there,because the little red "belt broken" light hasn't come on yet.

I always wonder how many perfectly good belts have been thrown away for no other reason than Mr Mbw says you need to buy another one from them.

I bet it breaks tomorrow now

 

[davegs]

Changing one on a friends 1998? 1100 at 86,000 on it's ORIGINAL belt, looked like new!. cahanged it anyway but amazing. Changed on on My1150 at about 55000 and it had started to split.
Dave GS

 

[kostas_patra]

I changed my alt belt at 80kkm at my 1100gs
it looked like new
no damage at all

1100 uses the 61mm alt belt and the 1150 until '03
1150 '03 and on, uses 595mm alt belt

Be careful when changing the alternator belt, the right screw, which lifts the alternator and pulls the belt, is anticlockwise and the usual torque wrenches do not make a click on that rotation.
Just remember that the belt when is properly tensioned can’t be turn over 90 degrees

changing the alternator belt at your garage, with all the tools on your feet, is an easy job , just undo the 4 screws of the cover and the 3 of the alternator, but not so easy at the road side !

ps. the original alt belt is actually contitech, as bmw does not manufactur belts. the type is pk4 and the length as told before is 611mm

 

[MattW]

Thanks for the replies.
I'm assuming that my belt is a normal one - I'll get one ordered.

 

[Steptoe]

My only concern is that I believe very early 1100's (and they don't come any earlier than mine) might have been fitted with some sort of weird belt which uses special pulleys and is a dealer only job?

The very early 1100 models did have a unique belt and pulleys job.

If you wanted to use the later belt you had to change the pulleys at the same time for the later type.

It's years and years since i've seen an old set up ( and even then only a couple), and i'll be fecked if i can remember in any great detail what the difference was

 

[(RIP) ugg]

If ye gona just take a spare belt wi ye.
Make sure ye can remove the bolt holding the oil pipe on.

Mine is ceased up , i left it coz we didnt have time before our last trip.

It would of been a bugger to change the belt on the road ,without a heat gun or whatever we needed to remove the bolt.

Worth checkin old boy.


ugg

 

[MattW]

The very early 1100 models did have a unique belt and pulleys job.

If you wanted to use the later belt you had to change the pulleys at the same time for the later type.

It's years and years since i've seen an old set up ( and even then only a couple), and i'll be fecked if i can remember in any great detail what the difference was

Thanks Steptoe.
From what I can see of mine it looks just like a standard 4 groove belt / pulleys. I've ordered one anyway - I guess I'll find out when I come to fit it (running out of time, so probably after next weeks trip)

 

[MattW]

If ye gona just take a spare belt wi ye.
Make sure ye can remove the bolt holding the oil pipe on.

Mine is ceased up , i left it coz we didnt have time before our last trip.

It would of been a bugger to change the belt on the road ,without a heat gun or whatever we needed to remove the bolt.

Worth checkin old boy.


ugg

Thanks ugg (19mm spanner for the breather behind the cover I believe). We're only off to Scotland for a few days - not like we're heading into North Africa - plenty of garages / breakdown services if the worst happens

 

[DrFarkoff]

Any Motor Factors 610 PK 4 standard belt kept in stock 1mm shorter than BM but unlike the 1200s the 1100 is fully adjustable it's just a barsteward working with the oil pipe that has to come off

So If you haven't Practise with taking it off when you are not stressed out! in fact change the fecker asap run for some miles and adjust once before ya leave it'll be fine!

 

[Trullion]

According to Haynes the maintenance-free belt was fitted to 1100GS engines from engine number 389461130. Modified pulleys were fitted at the same time. You can tell if the later set-up has been fitted to an earlier engine because the old top pulley was made of aluminium whereas the new one was made of steel. The old bottom pulley had three spot welds on the front; the new one didn't. The original set-up required adjustment every 12,000 miles. The later maintenance-free belt just required replacing at 36,000 miles. I don't know what year the change was made but my '96 RS either had the original set-up changed or was fitted with the maintenance-free belt and the later-type pulleys from the outset. It's the same as my 850GS. I simply pass on what is in Haynes, though the information does accord with both my bikes.

Hope this helps answer your original question.

 

[MattW]

According to Haynes the maintenance-free belt was fitted to 1100GS engines from engine number 389461130. Modified pulleys were fitted at the same time. You can tell if the later set-up has been fitted to an earlier engine because the old top pulley was made of aluminium whereas the new one was made of steel. The old bottom pulley had three spot welds on the front; the new one didn't. The original set-up required adjustment every 12,000 miles. The later maintenance-free belt just required replacing at 36,000 miles. I don't know what year the change was made but my '96 RS either had the original set-up changed or was fitted with the maintenance-free belt and the later-type pulleys from the outset. It's the same as my 850GS. I simply pass on what is in Haynes, though the information does accord with both my bikes.

Hope this helps answer your original question.

Thanks Trullion - very helpful.
I can't quite reconcile the engine number you quote - it seems to have too many digits compared to mine (the final zero?). I guess the only way will be to take it to bits and take a look but as this means engine bars etc I'm out of time before my trip next week.

thanks again

 

[Trullion]

Sorry Matt - my mistake (senility setting in.....). You're right; I put an extra digit in. The correct number is 38946130. FWIW according to Haynes all R850/1100R and 1100RT models had the maintenance-free belt from inception. From the data in Haynes this means that the change must have happened in 1995 when the R models were introduced. Only the early GS and RS models ever had the belt requiring adjustment every 12,000 miles. I now know that my 96 1100RS had the new belt from new.

I'm sure mankind will benefit greatly from this information.