That is the Aquamist water injection pump. Aquamist stopped making those pumps in 2009 so finding parts to fix them is a challenge. Hands down they are the best water injection pump ever made, especially for mounting on a motorcycle. You can read about their current products here: http://www.aquamist.co.uk/cp/cp1.html Their current pumps are made by Shurflo and are almost three times the size.