Loss of power at high revs with a droning sound

[maximusgnarl]

Hi.

Been away for a while and the bike had been stood unused.

Problem started about 18 months ago.
When travelling about 70-80mph the engine kind of makes a noise like it's running out if fuel ( a sort if droning noise)
I had thought it may have been the generator as I broke down a year ago and found it it was that. A year later I finally managed to get my ass into gear and fit a new one which works fine so I'm discounting that.
Only ridden it the once to my new house in scotland and the drone was still there. Problem is I don't have a garage at the new house so it working outside when it's dry

Bike is

Nc29 rrn 1992
K&N filter (just cleaned and oiled)
Stage 1 dynojet
SS system with race can
New plugs and oil and clutch 100miles ago

I have a carbotune and all seems ok

I'm thinking it may be the carbs but as time and lack of garage space makes it a pain to work on I thought I'd ask some others where they'd start looking first.

I have a Haynes manual and I'm quite happy doing most jobs

If it is the carbs is it best to overhaul and replace all the seals so you only do it the once?

The only other thing i can think of is that maybe part of the dynojet kit that you glue is has come loose after 10 yrs. ..possible or just being paranoid?

Thanks

[cbr400rrn]

Is it in every gear that you hear the sound? What is the rev range you are hearing it in? How long have you had the ss system on it and what make is it?

[maximusgnarl]

Can't remember the make of the system. It's been refitted with new copper gaskets twice now to see if the raspy noise it made was a leak. I guessing it may just be a normal exhaust rasp/noise that that system makes. The droning came on way after the system was fitted.
I've really only noticed it in 6th (maybe 5th) at 9-12k rpm and if I just keep it at that then the drone starts and it feels like when you run low on fuel and need to put it on reserve fuel
I'm guessing at the revs as I'm concentrating on the road.

It's also had 2 new fuel filters in the last 2 years in case I had a faulty one

[Davez29]

If you have a stainless setup the rasp will be that, I had one and it sounded terrible and really annoyed me to the point of going out of my way to find an original setup. And if stainless it could be linked to your other problem, perhaps a hole in the rev range, right at that spot. You might get around it rejetting, then again maybe not, mine was at 2500rpm and although i tried it was forever present, bloody annoying in slow traffic.. If its not a stainless system then im talking BS I suppose.