Terrifying Screech!

[Cook1e]

2001 R1150GS about 80k, ABS removed yonks ago.

Bike recently serviced, been running absolutely fine. Parked up in the garage, on the sidestand for a couple of weeks.

Went to start it up this morning for a run to Whitby. Started in the garage in case the battery wasn't quite up to scratch, but it started fine. Left it to tick over while I backed it onto the drive and suddenly there was the most horrendous screech! Very loud, lasted only a second or two and the engine stumbled, but didn't stall.

No further problems, 150 miles or so to Whitby and back, bike's running fine.

What the hell was it? Alternator bearing? Fuel pump? It scared the shit out of me - I thought it was terminal.

Anyone had similar, or can cast any light? I wouldn't want to repeat the experience and I'm worried that if it recurs, it may indeed be terminal.

 

[GingerPickle]

You hit the starter button by accident. Scared the shit out of me the first time it happened.

 

[Cook1e]

I was standing next to the bike at the time, not touching it. I think I've done that before anyway - if not to this bike then something else.
It was several times as loud and scary...
Thanks for playing though, first response

 

[Nice 'n' Fat]

Alternator belt slipping

 

[Cook1e]

Alternator belt slipping

That did cross my mind for a moment, as I changed the belt at the recent service, but it wasn't that kind of noise really. Much louder, reminiscent of rending metal.

It hasn't recurred either, which I would have expected if it was the belt. Also, it happened when the engine had been just idling for 20-30 seconds and the charging light had gone out. A slipping belt wouldn't have caused the engine to stumble either.

 

[Nice 'n' Fat]

Did you put the bike away wet?

 

[The Other PaulG]

Alternator belt slipping

That was my thought too, belt or bearing. Even though, as the OP says, it's not obvious why that would tie in with the engine stumbling, it's where I'd look first.

 

[Cook1e]

No. What are you thinking?

My best guess at the cause of the noise was catastrophic bearing failure, but it ran absolutely fine for 150 miles, with maybe 4 or 5 stops and starts, straight afterwards.

 

[albatross]

I had a screech when I started her up and the starter seized, still got her up and running but fried the plate between the starter motor and the starter gear system..see enclosed pic after repair…..
otherwise I would agree it was the alternator belt,;

 

[Cook1e]

I had a screech when I started her up and the starter seized, still got her up and running but fried the plate between the starter motor and the starter gear system..see enclosed pic after repair…..
otherwise I would agree it was the alternator belt,;

It started fine and ran for 10-20 seconds before the noise. Also started fine several times afterwards. Pretty sure it wasn't the belt, see above.

Thanks for playing though

 

[Cook1e]

I'm leaning towards early warning of alternator bearing failure. I'll maybe have the cover and belt off and give it a spin/wobble.

Is the alternator as much of a bitch to remove as it looks?

 

[Spout]

Your garage door needs greasing

 

[Cook1e]

Your garage door needs greasing

Not so daft - if it had been windy you might have been right

 

[DrFarkoff]

I'm leaning towards early warning of alternator bearing failure. I'll maybe have the cover and belt off and give it a spin/wobble.

Is the alternator as much of a bitch to remove as it looks?

I think I would lean toward the belt , Yes it can make the engine stumble

"The clue is in the battery was low" the load is really large as the alternator pumps current in

Belt slips and you get the Scrreech, then the Belt grips and the Engine stumbles as it has a heavily loaded alternator slowing stuff down rather rapidly

It the alternator bearing was that bad it would likely have failed in the 150 miles

 

[Cook1e]

I think I would lean toward the belt , Yes it can make the engine stumble

"The clue is in the battery was low" the load is really large as the alternator pumps current in

Belt slips and you get the Scrreech, then the Belt grips and the Engine stumbles as it has a heavily loaded alternator slowing stuff down rather rapidly

It the alternator bearing was that bad it would likely have failed in the 150 miles

So many replies suggesting the belt is making me think you might be right, although I was sure it wasn't a belt-slipping noise.

I'll check when I take the cover off and let you know. May be a while though, as my other bike's on the bench ATM.