Battery light came on while riding.

[Hermes]

Luckily I made it home (15 miles)allright with power to spare in the battery. Battery is now being charged and taken the charge.

My suspicion, broken belt, faulty regulator or a faulty alternator.

Can you suggest a process of elimination for a proper diagnosis, maybe there is a quick way to isolate the cause?

 

Btw, after 50K this is my first issue with the bike, not bad, however, so close to the UN Rally it's a bit unnerving.

 

Thank you

for your help.

 

Jurgen

[Boffin]

Just loosen the alternator belt cover and have a look. If the belt has failed (most likely) then you need to remove a sharks fin to get the cover off and replace the belt.

 

Andy

[Hermes]

Thanks Andy, I suspect the sharkfin is part of the left side panel?

And, do I need to take off the pipes, I suspect not.

 

Jurgen

[Boffin]

The easy way is to drop the left hand side panel, then the shark-fin shaped part on theat side. Then 4 bolts and the cover will just squeeze past the pipes to come off.

 

Andy

[kcscout]

If it is the belt, This thread may be helpful..

 

Of course, if the 1150 and 1100 use different belts, then that thread is useless. Good luck.

 

The sharkfins are the two pieces that are left attached to the bike when you take off the big pieces of tupperware. It'll be obvious, they look like a shark fin (assuming the shark is swimming upside down). The pipes stay on.

[Hermes]

Ok, good advice, thanks for the tips and lets hope it isn't anything more involved (metaphor for expensive).

I will post when I have checked the belt.

Jurgen

[barncobob]

have you replaced the belt previously. i believe it should be changed at 32K.

[Paul Mihalka]

have you replaced the belt previously. i believe it should be changed at 32K.

Depends wether the "50K" is km or miles. 50K km is just over 30K miles.

[Hermes]

Guilty as charged

 

I haven't changed the belt at all and the 'K' stood for thousand, thousand miles that is. So I have been negligent, just glad this happened 15 miles from home and not somewhere out there.

[PapaJ]

My service manual say to change it at 24K miles. I just did one, used a goodyear Gatoback belt #4040245. Cost $10 vice the $24 the dealer wanted. Went on easy, dropped the bottom section between the side panels and then the L side shark fin.

The cover came off, down and left very easily. The hardest part was getting enough extensions together to reach the bolts from the front to torque them to spec. I couldn't torque the upper bolt so I just tightened it snugly with a boxed end wrench.

[Hermes]

Ok, good news, (sort of) it's the belt, when I loosened the cover the broken pieces came tumbling out. I have a Dayco 5040240 so I am in business to re-install.

 

Q1:

How do I generate some slack to get the belt over both pulleys (loosen alternator??), just put it in place and crank motor over??, or what else).

Q2:

How do I determine and adjust belt tension?

 

Thanks for your help.

Jurgen

[Boffin]

Ok, good news, (sort of) it's the belt, when I loosened the cover the broken pieces came tumbling out. I have a Dayco 5040240 so I am in business to re-install.

 

Q1:

How do I generate some slack to get the belt over both pulleys (loosen alternator??), just put it in place and crank motor over??, or what else).

Q2:

How do I determine and adjust belt tension?

 

Thanks for your help.

Jurgen

 

Loosen the alternator and lower it. Then place the belt over the pulleys and with the bolts just nipped up lever up the alt body until the belt can be just twisted through 90 degrees with effort. BEWARE - the lead from the HES runs under the alternator body so watch where you put the lever.

 

With the belt at the right tension, tighten the upper right nut then do the others.

 

Andy

[Hermes]

Thanks Andy, that's the info I needed. Where is the best place to apply the lever (long screwdriver?) to avoid the HES (and what is a HES anyhow?), would the lever be center below the pulley or on the left or right on the alt?

Jurgen

[Ken H.]

There is another way to tighten the belt without levering on the alternator. Actually it's the OEM way: The left side bolt you will notice is actually a nut on a stud. Behind that stud is a cam affair that raises and lowers the alternator. There is a factory BMW tool, looks like this:

 

 

Or you can get an appropriately threaded 'acorn' closed cap nut. When you turn that stud with the nut the alt. goes up and the belt tightens. Then you tighten one of the other bolts to hold it in place. Replace the tool with the orginal nut and tightent them all.

[Hermes]

Thanks for that Ken. I have to go into town Fri, and if reasonably priced will pick one up.

 

Thanks all for your input, you have given me the courage to undertake this myself.

 

Jurgen

[Jim Moore]

Tool, schmool. Big ol' screwdriver under the alternator. Lift and tighten. Simple. I've spent more time typing this than it takes to do.

[Hermes]

Done.

I replaced the belt. I found it easier to take off the left panel, the glove compartment and the air intake. That allowed me to place a long screwdriver from the side underneath the alternator and apply upward pressure while tightening the alt.

I also found all kinds of fluff (belt debrie) in various crevasses behind the panel, and that reminded me seeing a day earlier while riding, all sorts of 'stuff' flying off the bike. At the time, I thought I was blowing away a mouse nest and paid no attention. Guess the belt started stripping then and blew som fluff out of the fine grill on the cover.

Note to myself: Don't ignore flotsam and jetsom flying off bike.

Thanks all for your encouragement.

[kcscout]

Happy Trails...

 

Congrats on a job well done.