You also have to be careful no matter what you use. You don't want to damage parts from too high a temperature, damage the paint or worse, force grease out and water in bearings and bushings. Washing dirt bikes, for example, some people have no clue. They put the nozzle too close and draw grease out of the suspension linkage allowing water in to replace it. It's pretty common for kids to not think too much and blast water down the muffler/silencer destroying the packing inside. On a 2 stroke especially it's very easy to tell who needs new silencer packing. Equipment might be a little more forgiving but you still have to be cautious with a washer. One thing you never want to do is blast away at engines with ECM's and electronics. I've read on here of people having constant problems because the wiring and electronics got wet.