Cam chain rattle sounds similar to a light sewing machine noise, but at first would be more noticeable on start up until the oil gets warm, then would normally disappear after 5-10mins of riding. It would only persist after a few months, which would normally mean you're in between clicks on the tensioner, but the sound would remain when sitting idling. Normally more noisy in winter due to oil temperature. If the tensioner was knackered or the chain worn then you'd have been asking about it ages ago.
These gearboxes whine in general, a louder end can sorted that out for me, but check your oil level to be safe.
Any air leak at all, rubbers included, would result in "bogging down", meaning any sharp throttling would literally feel non responsive and quite simply terrible to control, i think you'd know straight away if it was that.
You could quickly try a TPS check to rule that out, see if it's positioned correctly and if it isn't, or it's kaput, then it can really affect the running and sound of the bike.
You need a fully working TPS to do a carb balance, plus a breathing clean air filter, so a check is necessary, and it only takes seconds to do so is one to rule out firstly anyway.
