I have just gotten my bike back from the dealer, they replaced my water pump under warranty but didn't replace the oil filter or clean off the clutch cover emulsion ( milkshake/mayo ), but now I am hearing a slight "loose" noise, at idle.

Could this be reduced oil flow from the previous contaminated oil? How do you flush this? Should I just keep riding and hope it will clear?

Any help would be appreciated.

Thanks

God now it's worse will post video

Can't access video - rear cylinder cam chain rattle?

What he said^^^*.

If the oil and filter hasn't been done then the filter will be catching the water that's in the oil. If it's caught oil then it won't flow oil = low flow and pressure. Does the oil light stay on longer when started from cold. Pull the oil filter out and see if it's is water damaged. If it is I would change the filter and not the oil. Run the same oil until your sure the water is out then replace.

Sorry boys, video was set to private, try now

Sounds like cam chain slap to me, at least on my phone - oil and filter change as suggested above - dealer should have done that as a matter of course.

Dealer changed oil ( not 10w50 as specified) but not the filter (which should be part of any water pump rebuild), thing is it wasn't making that noise before the water pump rebuild.

My theory is that the filter is wrecked so the by pass valve is open, meaning pressure is not enough for the tensioners. Funnily the oil pressure light is not on.

Any way dealer is picking up bike today, am I within my right to get it repaired for free, have only ridden 50 km since rebuild, have had the bike for 10 months

I had the same. The round filter is filled with sludge and can't pass oil, so the heads can't be reached by the oil. This is where the sound comes from.
Chance the oil and the filter, beacuse it;s half oil and half coolant. Bad for the bike!!!