Dr Downpipe Motorcycle Exhaust Cleaner – 500ML Spray Bottle. Yep another cleaning review again, and this time something a little different. Exhaust cleaning that comes in the form of Dr Downpipe spray cleaner. I been a follower of his work for a while and it was time I did some dedicated cleaning on this area, so placing my order via Amazon I hoped it would arrive quick, but no matter were you order it seems a week delay on it arriving. So placing my order and then booking the time in my head to do it at the following weekend …