1200 GS alternator seized - help required

[Atillo]

Tried to start my 04 1200GS the other day after it had been laid up for a couple of months and it was very slow to turn over, made a bloody awful screeching noise and produced smoke from the front engine cover. Closer investigation revealed that the alternator pulley is static and the belt is slipping over the pulley making the hideous noise and smoke.

It looks to me as though the alternator bearings have seized and a closer look shows that the casing of the alternator has cracked along the lines of the bolts that hold the alternator casing together.

My questions are;

1) is this likely to be a correct diagnosis?

2) can the alternator be refurbished or will I need to get a replacement?

3) where is good to get a replacement (BMW or pattern)?

Any help gratefully received - I want to get back on the road soon!

CHeers,


Angus
Bristol

 

[ianran]

Tried to start my 04 1200GS the other day after it had been laid up for a couple of months and it was very slow to turn over, made a bloody awful screeching noise and produced smoke from the front engine cover. Closer investigation revealed that the alternator pulley is static and the belt is slipping over the pulley making the hideous noise and smoke.

It looks to me as though the alternator bearings have seized and a closer look shows that the casing of the alternator has cracked along the lines of the bolts that hold the alternator casing together.

My questions are;

1) is this likely to be a correct diagnosis?

2) can the alternator be refurbished or will I need to get a replacement?

3) where is good to get a replacement (BMW or pattern)?

Any help gratefully received - I want to get back on the road soon!

CHeers,


Angus
Bristol

1) Yes?

2) Probably no and yes?

3) BMW New, Motobins etc 2nd hand?

Good luck!

 

[Ravenbyrne]

Couple of things you could try........

Remove the black plastic cover, remove the primary plugs, select neutral and see if you can turn the lower pulley, a 36mm socket will make life a little easier.

With the bike in neutral the lower pulley should turn freely. If it moves then move to the next step.

Now select 6th and try to turn it again (clock-wise direction) if it moves it's not seized.

What you describe as cracking might just be paint flaking, difficult to tell without seeing some photo's

What mileage is on the bike

 

[Atillo]

Ta for the speedy responses!

I turned over the engine and the lower pulley moved but top one was static. The belt is not slack and earlier smoke from the front cover suggests that there is plenty of friction between the belt and the top pulley. Alternator casing is definitely cracked along the line of the joining bolts as I could see the bolt threads through the gap although corrosion of the surface of the cracks suggests that these are probably not new features. The bike has about 38k and I've had it since September.

Cheers

 

[Ravenbyrne]

Ta for the speedy responses!

I turned over the engine and the lower pulley moved but top one was static. The belt is not slack and earlier smoke from the front cover suggests that there is plenty of friction between the belt and the top pulley. Alternator casing is definitely cracked along the line of the joining bolts as I could see the bolt threads through the gap although corrosion of the surface of the cracks suggests that these are probably not new features. The bike has about 38k and I've had it since September.

Cheers

That sounds very serious and as far as I am aware the alternator is not serviceable. Could be that the windings on the coil have failed catastrophically and have jammed the armature in the alternator.

You could try removing the belt from the pulleys (it's due replacement anyway) stick a socket and ratchet on the nut of the alternator and see if you can turn it that way.

Can you post a photo of the cracked casing

 

[Deleted account 190920001]

anything is serviceable if you can get the parts, trouble here is the cracked casing. Possibly could be welded up and the bearings or whatever replaced but your easiest and possibly cheapest route would be to replace it altogether. They come up from time to time on Ebay or Motorworks if you want second hand.

 

[Atillo]

Sorry - I can't post any pics at the mo. as the bike is stuck round at a mate's house in Somerset about 20 miles away! I vaguely remember reading somewhere about sudden failure of the glue that holds magnets in place that can jam up alternators/starters so maybe something like that has happened. I'll get the alternator off and have a good look before getting a replacement just in case it's not as catastrophic as it seems! Will try to post some pics of the casing then.

cheers for the advice

 

[Pukmeister]

The glue issue is for the pole pieces in the starter motors on earlier GS variants.

The alternator has a claw rotor and stator windings hence does not have glued-in pole pieces.

My guess is that the bearings have become internally corroded due to the ingress of dirt and moisture, seized and caused the casting to crack as the whole affair has tried to turn under the increased torque of the rotor/stator twisting together under the tension from the slipping belt.

 

[Ravenbyrne]

Might be worth investigating

http://cgi.ebay.co.uk/BMW-R1200GS-A...06?pt=UK_Motorcycle_Parts&hash=item3a63d75856

 

[Myke Rocks]

A quite common complaint on some cars

The clearance between the pole pieces and the rotor is quite tiny, and the rust build up when laid up causes the alternator to sieze, and the drive belt to burn off on a cloud of stinking smoke.
Remove alternator belt cover, remove remains of belt, put socket on tee bar and fit over alternator pulley nut. rock gently back & forth a few times and alternator will free. spin freely a few turns. Fit new belt, start & all is well. With engine running, take airline & blow out alternator.
Job completed.

Myke

 

[jontym]

mine siezed at 30'000mls while out on the bike,alternator cracked along length of bolts, also through vents in alternator body.Bought almost new one of flebay dealer for 50 quid,seems to be quite a common problem on early 1200's.

 

[Atillo]

Top tips folks - definitely worth a try and corroded rotor bits may be more likely than sudden bearing failure. It all seemed fine before it was cruelly abandoned during the winter. I'll try to free the alternator first. It was suggested that a special tool is needed to get the belt on and off the pulleys -is this the case and what are the risks of not using said tool?

 

[jontym]

Top tips folks - definitely worth a try and corroded rotor bits may be more likely than sudden bearing failure. It all seemed fine before it was cruelly abandoned during the winter. I'll try to free the alternator first. It was suggested that a special tool is needed to get the belt on and off the pulleys -is this the case and what are the risks of not using said tool?

I was the only tool needed to change the belt.

 

[Ravenbyrne]

Top tips folks - definitely worth a try and corroded rotor bits may be more likely than sudden bearing failure. It all seemed fine before it was cruelly abandoned during the winter. I'll try to free the alternator first. It was suggested that a special tool is needed to get the belt on and off the pulleys -is this the case and what are the risks of not using said tool?

I've changed mine without the special tool, it's easy peasy. Your belt requires changing now so get a new replacement and just cut the old one off.

When you've got that much done let us know and I'll tell you how I installed my new belt

 

[Atillo]

Jontym - you must indeed be special!

Ravenbyrne - thanks for the advice, I'll get a new belt ordered and try to free up the alternator. I checked out the fleabay alternator but it's in Lithuania which is probably beyond my comfort zone for online shopping! West Yorks is more like it for me. I'll give you a shout when I'm ready to replace the belt.

Cheers m'dears!

 

[patzx12]

Let me know if you need an alternator, i have one

 

[Atillo]

Thanks fella, will let you know.

 

[ducatiparts.110mb]

Fer, chrissakes, the casing is cracked. How much investigation is necessary before you accept the inevitable and just buy a replacement?

 

[Deleted account 190920001]

Fer, chrissakes, the casing is cracked. How much investigation is necessary before you accept the inevitable and just buy a replacement?

+1

 

[Atillo]

I was thinking perhaps just enough investigation to make sure that it can't be salvaged before shelling out a load of bucks on an unnecessary replacement. I could be wrong though!