Alternator belt change

[Steptoe]

Alternator belt change

The pictures are taken with the fuel tank removed for better viewing and pictures, but you can do the job with the tank in situ .

If you have crash bars fitted,and they have the bar running across the front of the engine, you have to remove the bar to get the plastic cover off.

To remove the plastic alternator cover, undo the four bolts (4mm allen head), be careful and use a good fitting tool. There are two each side, and on the right hand side is an oil pipe ( just ignore it)





Slide the cover down, and to the right. And it’ll come out from the bottom




The cover





You need to undo the three 13mm hex head bolts/nuts.

One each side, and one at the top.







. I use a 13mm ring spanner



On 1100 models, you have an oil breather pipe. Held in place with a 19mm hex bolt at the top, and a allen bolt at the bottom ( 6mm head)

Here’s the pipe



Undo the bolts, no oil will come out, and remove the pipe. 1150 models don’t have this pipe.







Squeeze the belt together, and the alternator will drop down, allowing you to remove the belt.

Some servo bikes have a plastic cover over the alternator pulley, this can get in the way, stopping the belt from coming off. Just pull the cover off.

Servo alternator


Put the new belt on , and tension it. The workshop manual shows the rear of the L/H side bolt being turned with a torque wrench. This raises the alternator, so you can tension the belt at the correct torque. Read the manual if you want to do it this way. And you must remove the tank to get at the rear of the bolt

Where the bolt is located if adjusting the belt by the book.



I raise the alternator with a small pry bar, but I know what tension the belt has to be, so use the official method of tensioning if you’ve never fitted a belt before.
If using the bar under the alternator method, be careful of the ignition wire running underneath the alternator. If you trap this, you’ll sever the wires and the bike won’t start.

Putting it all back is the reversal of the above .

 

[Welshman]

Weren,t there some models, with a different top pulley which stops the cover coming off so easily?

Welshie

 

[Steptoe]

Weren,t there some models, with a different top pulley which stops the cover coming off so easily?

Welshie

Look at the second picture from the bottom, and read the text

Unless your talking about the very early 1100 models, which also needed the pulleys changing for the later belt - i haven't seen one of those in over 6 years. Most 1100 have had their belts changed since 1994

 

[Welshman]

Look at the second picture from the bottom, and read the text

Unless your talking about the very early 1100 models, which also needed the pulleys changing for the later belt - i haven't seen one of those in over 6 years. Most 1100 have had their belts changed since 1994

No you are quite right, my brain was not in gear, I was still thinking about mine, which is a 99 1150 so this would not apply I think.

Welshie

 

[Taff]

Brilliant. I'm a self-confessed plank when it comes to anything mechanical, but I do enjoy watching someone who obviously knows what they're doing.

Pity you live the other end of the country from me.

 

[Mzokk]

Brilliant! I'll have to do that job soon 26.5k on the bike at the mo.

 

[lkyphl]

When using the "pry bar under the alternator" method, is the correct belt tension that which allows one to twist the belt 90 degrees ?

Phil

 

[Mutley]

Preventative maintenance?

Steppers, when should I replace the belt on my 1150 Adv for preventative maintenance (age / mileage?)?

 

[Steptoe]

When using the "pry bar under the alternator" method, is the correct belt tension that which allows one to twist the belt 90 degrees ?

Phil

If you don't know, i'm not saying. Due to the way people fail to manage such simple procedures i'm not going to tempt fate and have people blaming me for their inadequacy. Thats why i didn't show it being done in any pictures.
If you don't know what the correct tension is on a belt, do it by the book.

Steppers, when should I replace the belt on my 1150 Adv for preventative maintenance (age / mileage?)?

Service schedule says change at 36K miles. But if you run a pimps/goldwing/sad bike lit up like a christmas tree , i'd change it at the 30K mile service. The more load you put on the alternator, the shorter the belt life.

 

[gypsy]

How much are these belts please ?

 

[snoopy]

35.4k on mine too. Great write-up

 

[blues n twos]

How much are these belts please ?

About £11 from BMW for an 1150, Prob a bit cheaper from our Steptoe

 

[frank]

Altenator belt

Hi to you all,this is my first post so please be gentle.
Great detail in the thread, but there maybe a problem with a repair when the belt snaps away from home with just the standard tool kit.It happened to me on my 1150GS. Here's how to over come the problem, assuming you have a spare belt, which I did.
Firstly your charging light will glow to inform you of a problem. Stop as soon as possible, assuming you have a spare belt because as soon as the battery voltage drops below 12v, the bike will stop anyway and you will not start the engine with out a tow once you have repired the broken belt.
Remove all covers as stated by Steptoe, your tool kit will do this,but it is not up to removing or loosening the 13mm nuts to slacken the altenator.Remove the old shreaded/snapped belt.
Remove both spark plugs, engage top gear,Place the new belt over the bottom pulley and guide it on to the top pulley as far as possible, then with the help of a friend (or someone, who may stop to ask if they can be of assistance) ask them to slowly turn the rear wheel while you guide the belt onto the pulley (watch you don't trap your fingers), this will drive/force the belt on to the top pulley. Hey presto the jobs done, and belt tension should be as tight as before. Replace all covers etc, and you should be able to start the engine as normal.
This happened to me after aprox. 40,000mls and I'm still running the same belt with no adjustment at 75,000mls, I also have a spare belt under my seat ready for next time.
Hope this is of some use,
Frank

 

[blues n twos]

Hello mate and welcome to the site,

Thanks for the tip, I have had a belt sitting on my kitchen side for two months now and I have been trying to find a spare afternoon to fit it. My bike is on 32k now and i'm to Austria for a 3k blatt next week

I am going to try the Steptoe way with the tank on and if I get arsed I will give yours a go.

I have the Hepko and Becker bars on and it's a pain taking them off.

Jon

 

[lkyphl]

If you don't know, i'm not saying. Due to the way people fail to manage such simple procedures i'm not going to tempt fate and have people blaming me for their inadequacy. Thats why i didn't show it being done in any pictures.
If you don't know what the correct tension is on a belt, do it by the book.

The three I've fitted to my 1150 (163,000 kms) have been set by the 90 degree method. I've never met anyone who carries a torque wrench on their bike, so when fitting a belt using the pry bar method when miles from nowhere, it seems safer to me that people have some idea of what tension to apply. It can always be reset using a torque wrench later.

Thanks for taking the time and effort to provide the write-up,

Phil

 

[Steptoe]

I am going to try the Steptoe way with the tank on and if I get arsed I will give yours a go.

I have the Hepko and Becker bars on and it's a pain taking them off.

Jon

It'll take you longer to take the spark plugs out than to undo the three 13mm nuts !!

You need only to remove the front crashbar support across the alternator cover

. I've never met anyone who carries a torque wrench on their bike, so when fitting a belt using the pry bar method when miles from nowhere, it seems safer to me that people have some idea of what tension to apply. It can always be reset using a torque wrench later.



Phil

Don't now anyone that carries a pry bar on their bike

If they know how to fit a belt at the side of the road, then they know.

If they don't know how to fit a belt at the side of the road, then the roadside assistance man will know - But no good knowing if they don't have a belt with them.

I know what you mean, and i'm only jesting, not being superior

 

[Colban]

I changed mine after 47000 miles on the 1150.Mine looked OK,no cracking or loose bits,but that was just mine.I now keep the old one as a "get you home" spare on the bike.Also,use a padded pry bar on the alternator so you dont distort the teeth.Damage to that (teeth/rings) will shorten the belt life.

 

[Steptoe]

Also,use a padded pry bar on the alternator so you dont distort the teeth.Damage to that (teeth/rings) will shorten the belt life.

Don't lever the teeth/ring, even with a padded bar

 

[monkeyboy]

Hi to you all,this is my first post so please be gentle.
Frank

Alright Frank - I've done exactly that the last three changes on my R1100S and been riding with GSs in the middle of nowhere (like the side of the mototway in Malaysia) that has done the same on more than one occasion - takes about 15-20 mins and we didn't bother with the plugs removal - just put it in gear and turned the back wheel or used the wheelbrace on the crank bolt I seem to remember. In my experiance the belts seem to 'shred' more than stretch so the tension has always seemed 'sufficient' using this method.

Maybe I'll do it properly next time now I know how

Jason

 

[Bateman]

I was at CWs yesterday and Darren said that BWM have changed the timing on when the belt needs to be changed on the 1150GS. The book says change at 36,000 miles, but it is now done at the 24000 mile service. I am on 27000 miles so maybe I will change mine/attempt to change mine/take some wine round to PikeyDaves and bribe him to show me how to change mine.....