Info on "grades" of pressure washers
When shopping for a pressure washer, keep in mind that there are two "grades" of units on the market these days: vertical and horizontal. In the old days, the pump unit was driven by either a gas or electric motor with a horizontal output shaft. A few years ago, the manufacturers saw the home market rising and came out with vertical shaft units being driven by essentially lawn mower engines. Pressure is pressure so there is no difference in performance. But, these are considered disposable units for occasional use. Like cleaning the backyard deck once a year and blowing off the driveway. They are generally not worth repairing should the break.
As for how much of a unit you need, keep in mind it takes pressure AND flow to clean. Pressure sells but the flow rate is really more important in most situations. Three gallons per minute is about my minimum. 1500 psi would be minimal, too. I like 3000 at 4gpm for light industrial work
Much has been said in our industry about using pressure around bearings, gaskets and such. Good advice. Remember that the pressure exerted on the surface drops like a rock with every inch you move away from the bike. Get up close when cleaning the bottom of a fender, back off when you gear near the hub. If you use chemicals, dwell time (soaking) is almost as important as pressure so long as you don't let it dry on the surface.
As for the brands available, keep in mind that there are drives and pumps. The rest is pretty much generic unloaders, injectors and such. All the pump manufacturers these days are good. Honda engines drive most of the gas driven units. Those things are as reliable as a brick!
There is very little profit margin in this cold water pressure washer market. Sam's, Northern Hydraulics, Home Depot and others have gotten the market to where a local dealer can only make about $50 to $75 on a unit. Tough for them but good for the consumer.
One gadget that helps a lot is a "rotary nozzle". One of the first was a unit called a "Dirt Killer." Rotomax, Turbo Nozzle and other names are for other brands. These accessories are essentially spray tips that go on the end of your gun instead of your usual 15, 25 or 40 degree fan spray tip. They put out a straight, tight spray stream (0 degrees) so all the cleaning power is hitting in a tight area. But, they rotate the stream in a tight circle giving you about 4" or slightly more "pattern." Great tools for helping a smaller pump compete with the bigger ones. One word of caution, though, these nozzles are pricey but should last a long time if you take care of them. What makes them "rotate" inside the nozzle is a small piece on a ceramic seat. When the gun is pointed toward the ground, the parts are seated. Point the gun up and pull the trigger and the internal piece slams against the ceramic seat and can shatter it. Don't just drop the gun, treat it like you would a shotgun or rifle.
One last note on pressure washers and I'll shut up. Please be careful when pointing the gun. Even at 1000psi, you can cut skin. The problem comes in that you aren't just scrubbing away a layer or two on top. The water (with any contaminants) is entering your body and rearranging tissue. Take any water-related cut seriously. Better yet, make sure your spray wands are long enough that you can't easily hit your other hand should the gun slip.
By the way, I do industrial cleaning for a living and am also an authorized instructor of OSHA material. I have had pumps up to 10,000 psi and have friends who go up to 40,000 psi. Now, those are pumps that could make Tim "The Tool Man" Taylor get excited! Try cleaning your bike with one of these bad boys...;)
Todd "the international janitor" Turner
And yes, I admit to being chemically dependent. I even drop acid on a regular basis. But, mine is industrial and not for meant for human consumption.