2000 daytona 955i noise like air escaping

Hi, I have a 2000 955i Daytona with just over 10,000 miles on it. As much as I love this bike I am reluctant to ride it due to a strange noise it is making. The noise sounds like the escape of air you get when removing the air hose from your tyre after inflating it. It is difficult to pin point the exact area but I think it is from on top of the engine somewhere. It happens randomly but frequently at tick over and also whilst riding although I don't know if it happens at a decent speed as I would not be able to hear it. It really does put me off riding it but when I took it to my local Triumph dealer he just shrugged and said it would likely cost more to trace the noise than the bike is worth. Does anyone have any ideas please(other than find a new dealer)

 

Thanks for the offer Darkman, I may well take you up on that as it is only 50 miles away. I am a bit tied up for the next couple of weeks but after that I will get back to you

 

I tried that after checking the breather wasn't blocked but it made no difference. I also tried the cap off the coolant reservoir and it isn't there either.

 

Slight update. I took the tank cover off to check if I could hear it around the pressure cap as it only seems to start making the noise when it has a bit of temperature in it but that all seemed fine but the noise does seem to be down the top front of the engine, I just cant see anything move /pulse or anything else coinciding with the noise.

 

Final update. I popped into Destination Triumph at Wickham and they were really good in there, found the snag in under half an hour and all sorted under the hour. It was the IACV hoses had perished and were leaking but back to its brilliant best now.