What is this noise?!

http://www.youtube.com/watch?v=1ebgS5lfF4A

I started noticing it after an hour on the bike. Got home, turned off the ignition and had a look around. It faded and eventually stopped after 20 mins

Strange on that. Hope you figure it out

Well it has a sound like when the kettle has boiled. So me thinks its the rad cap. Have you had the radiator cap off lately?
If so its probably not been put back on properly. If not the rad cap might be stuffed and loosing pressure.
Also check around the radiator make sure no hoses are leaking.
Another thing I would look at is the fuel tank might have to much preasure so next time it does it undo the fuel cap and see if the noise stops.

I would go with radiator as well. Especially if that is coolant on the floor in the video.

+1 on the cooling circuit.

I think AGRO hit the nail on the head

Sounds like pressure build up in the coolant system which is pushing coolant out of the overflow and that is what your seeing on the floor!

Next time check the rad cap!

where does the sound feel like it is coming from?

I'm pretty sure it's coolant leaking but it smells like something else and it was so loud!. Also the coolant expansion tank was only half full unlike last time it dropped some coolant. I was going to open the rad cap but didn't fancy having it explode in my face. Haven't touched it for months either.

The sound, I'm pretty sure, was coming from the battery box though. When I went to start it this morning it wouldn't start so I'll have to research tonight or tomorrow.

I know exactly what that sound is its the battery over charging I'm afraid your rectifier is knackered I had the same problem on my old 05 reg superduke it boils the battery I got away with it not damaging the battery. Its a simple fix you just need to replace the rectifier which is located infront of the battery it the small electrical box with fins hope this helps.

Thanks! That would probably explain the strange smell as well last night. I've had a few battery issues lately so that explains that as well.

Opened up the rad anyway and it's full to the brim. Slightly gungy inside the cap as well so looks like cooling system is playing up again somewhere. Had the water pump shaft/seal replaced only 2 years ago as well.

Still fooking love this bike though.

most defenitely you'll need a new rectifier and battery, once you purched the new part make sure you check the voltage on the battery before and after starting the bike, it should be higher after you have started the bike and it should remain constant even if you are reving it.
this is just a precaution so nothing else is wrong to make the rectifier make such a high pitch sound. i also wouldn't recomend using the bike up until sorted, the least damage would be your fuses, worst a small fire or cooked harness.
plus remember to make sure the breathing hole (if you get a wet battery) is free of obstrucion otherwise you run the risk of explosion from pressure.
good luck with you repaires.

Nick

Wow, first time I've heard anything like that comming from a bike. I thought it sounded like a transformer overloading and about to explode. Good thing someone on this forum has already experienced this so should be easy fix.

Keep us apprised.

John

Just read on a Dutch speaking motorcycle forum about someone hooking up his motorcycle to a 10Amp charger for 2 hours.
He experienced the same whisteling noise...

First thing I thought was ' oh god, It's really fooked itself this time'.

Gonna order a new regulator tonight and I'll probably ditch the battery and stick the spare one in. I haven't had time to check but I think the leak might be from the battery cos it was a really strange smell that went with it.

Put a new regulator in Thursday evening and no problems since then.

Thanks to Raz who knew exactly what the sound was!