Not a good noise

[Hotwls]

Hi all . I've got a 96 Seca that I've been riding for a few years & am taking quite good care of it. I have searched the forums for similar issues but I have to put this one out there just in case it has happened to anyone else. The problem is a weird grinding noise that has started in the last few months only while moving. In the beginning it was just a slight tapping noise & while occasionally riding it I have been trying to pinpoint it . I took it to my mechanic today to try & fix it, explained the issue & got him to ride it so I thought it would be solved. I got it fully serviced & the engine runs beautifully, I thought the grinding noise could be the front wheel bearing but the mechanic removed the front wheel & said they were fine. He then said it could be the chain so I got him to change the chain & sprockets as well as it was time anyway. The mechanic then took it for a short ride up & down the road & said it was fixed. $500 later, I rode it home but after about 15mins , the dreaded noise was back worse than ever. I called the mechanic & let him know that I understood the work they did was necessary but the issue still isn't fixed so here are the issues.

It happens intermittently - I can ride it for a day without it happening but it's now becoming more constant & is now getting louder. I know damage is happening
It only happens while moving. It speeds up & slows down with road speed.
Cruising at low speed with minimal throttle brings it on (20-60kph) In any gear.
I can floor it fairly hard & it will disappear. Disappears at higher speed too.
The Clutch operates & feels normal. Changes gear normally too
The Oil was changed & nothing was unusual in it such as metal filings etc
After doing the chain & checking the wheel bearings the next thing to check will be the clutch as suggested by the mechanic.

I have not checked if it still happens while rolling in neutral ... Thats next then :wallbash:
I have had rare issues with gear changes such as gears not engaging like a phantom neutral between 2-3 & 3-4 but I put that down to lazy gear changes with my foot. Only on upshift not on downshift. Could this have anything to do with it ?

Oh yeah I don't have anywhere to work on it as I only have a footpath & on street parking at home so all repairs are getting expensive at a mechanic about a 20min ride from home.

Has anyone else had a similar issue ?