Dunno 'bout pushbikes, never tried, but for a m/c? Don't is my advice.
I had a go a coupla times. Really, you can do better with a hose and a washing up brush. Pressure washers are all brute force and no control - the only bits you can safely use them on are the bits that are easy to clean anyway. Using them anywhere near the drivetrain, exhaust, air intake, hydraulics, electrics or any bearings is a no-no, and any time you point the jet at a complex surface, dirty water gets reflected everywhere.
Elbow grease. Boring but highly effective!