Rough running at low speed is more likely to be the carbs needing balancing.
The rubber intake parts are thick and cracks take a very long time to get all the way through even if they look bad from the outside. Get some black silicone sealant and smear that into the cracks. You might want to do the same to the little rubber caps that fit over the vacuum take-off points too... I balanced my carbs a couple of days ago and found those caps quite badly cracked.
Poor throttle response might also be down to the cables needing adjustment/lubrication.
The cam chain does rattle at some points in it's life... eventually the tensioner decides things have got bad enough to move another click and it all quietens down again.
The rubber intake parts are thick and cracks take a very long time to get all the way through even if they look bad from the outside. Get some black silicone sealant and smear that into the cracks. You might want to do the same to the little rubber caps that fit over the vacuum take-off points too... I balanced my carbs a couple of days ago and found those caps quite badly cracked.
Poor throttle response might also be down to the cables needing adjustment/lubrication.
The cam chain does rattle at some points in it's life... eventually the tensioner decides things have got bad enough to move another click and it all quietens down again.