If you are a motorcyclist, there will most likely be one time or another when you need to tow a motorcycle on a trailer. Maybe a trip or picking up that new or used motorcycle. There are lots of articles on how to tie down a motorcycle, but few on how to check the trailer over before hauling that bike. Here is a good checklist you may want to run through before taking off down the road.
Be sure the trailer is rated for the amount of weight you will be loading on it. I have seen a few times where people try to put 2 good sized bikes on a very small trailer that was not built to haul such weight. The results can be catastrophic.
Is the hitch the appropriate size for the ball you are using? Typically right on the hitch it will say what size ball that particular hitch is made for. Usually on the ball somewhere it will also say the size. Be sure they match up.
Safety Chains. A must. I see too many people running around with trailers that have no safety chains. If for whatever reason you trailer comes off the ball the safety chains will keep the trailer and your bike from flying off any which direction.
Receiver locking pin. Be sure the pin is in the receiver and is secure enough that is will not come out.
Test the lights. Have someone in the vehicle and tell them to apply the brakes, along with left turn signal and right turn signal.
Check the bearings. Jack one side of the trailer up and spin the wheel. There should be no noise such as grinding. The wheel should have very little perpendicular movement. If everything looks good try the other side.
Inspect the frame and the tongue for cracks. The reasons for doing this are self-explanatory.