CHAIN
Stuart, yes! Initially if you closely examine your chain if it has dirt in it them you should clean it. If you clean it with diesel fuel and a stiff brush ( an old paintbrush that you can chop all but the last 1/3 off of) you will have diesel fuel splashed everywhere but your chain will be super clean. Then you will need to find a way to fling out the diesel, getting rid of it off of your chain, like riding it or very safely sitting on the bike with the centerstand down and sitting forward to make the rear tire be off of the goound and put it in secone gear holding the front brake on and your finger very close to the safety on/off switch incase it pops off of the centerstand... Prefered a ridearound the block twice...youwill hear your chain really making noise. Then while it is warm from the ride spray it with chain lube. MY personal preference is a silicone based lube as silicone doesn't attract accumulate dirt/dust like a grease would. and it will seep into the chain better. Back in the old days some of us actually had several chains and would melt wax and leave then in a hot wax for a while before removing them and hanging them to dry. That way you always had two spares and one on the bike. Nowadays chains lubes seem to hold on better, but you have to lubricate them often or you will not only ruin the chain but worse yet the sprockets. If you had access to a place that does Dry Film Lubricant Applications I would have the new sprockets done, I don't know if they do chains because they have rubber O-rings