You could make up a bung to put onto your inlet where your air filter goes and try pressurising the system, i just used a bit of metal tubing the correct diameter, welded a plate on the top drilled a hole through the plate and super glued a bit of inner tube with the valve in the hole, has worked upto a 18 psi so far, nice easy way of checking for leaks. just hook a compressor up to it and away you go.

Alex

EDIT: hope that makes...