This is a quick look at some of your transport options, and some tips for making the whole process easier on you and your equipment.
TRANSPORT IN OR ON A VEHICLE
Typically, a dirt bike transport vehicle would be a pickup. Back in the good old days, when truck boxes were big enough to carry a 4x8 sheet of plywood with the tailgate closed, you could pack a lot of dirt bikes and motocross equipment onto one. Today, the cabs are bigger and the boxes are smaller, so you can usually carry more riders than bikes.
The biggest challenges with pickups are the size of the box, and the height. To address the size issue, you're going to have to limit the number of motorcycles you transport. The number of motorcycles will depend on their size. I used to transport a 100cc, a 90cc, and a 50cc in a smaller half-ton with little problem. The tough part was finding enough room to transport all the gear I needed to take along as well. One option is to leave the tailgate down and keep things in the box with a cargo net, straps, or a home-made barrier.
If you prefer to have the tailgate closed but your dirt bike is just a couple inches too long – secure the front wheel at the front, on one side of the box, and then shift the rear wheel towards the other side until you have enough room to close the gate.
And that leads to strapping down the motorcycle itself when transporting. The tried and true method is to bring the front tire up against the front of the box, and then use tie downs from each side of the handlebars to the box. Hopefully your box has tie-down points. If not you'll have to add some. You can buy awesome tie down tracks like these or use some cheap eye-bolts and a few nuts and washers. Just make sure you anchor your tie-down securely. When you tie down the bike, compress the front forks. The resulting tension will keep everything in place during transport. If you're traveling for more than a day, release the straps enough to take the tension off of the forks when you're not traveling, then re-tighten when you hit the road. I prefer the simple cam tie-downs that you pull to tighten and press the small lever to release. Ropes are too much work for me, and the ratchet tie downs strike me as overkill. Mind you, if I was transporting my dirt bikes on an open, flat trailer or truck, I'd probably buy the ratchets for extra security .
If you ride enough, and don't use the truck to transport anything else very often, you can install wheel chocks or brackets. Usually, these are just for the front wheels. You can choose from a number of style with different options. From a simple channel to keep your front wheel from moving sideways, to locking mechanism that (technically) keeps the motorcycle from rolling as well. No matter how fancy the wheel bracket, I would still use tie-downs to A) help reduce shaking/vibration, and B) keep the bike in the truck if the wheel chock should fail.
Of, course, before you can transport it, you have to get the dirt bike UP into the back of the truck. You have four options that I'm aware of. Ride, push, pull, or lift. If you have the skill and the nerve, you can ride your dirt bike up a ramp, into the truck. I've done it a number of times, but really feel nervous every time. If you're a trials rider, no worries – you can probably ride it in WITHOUT the ramp.
If you're going to push your bike into the back of your truck for transport, seriously consider getting two ramps – one for the motorcycle, and one for your feet. Remember, the bigger the dirt bike, and the higher the truck, the more of a running start you're going to need to get the motorcycle all the way up. Getting 3/4's up the ramp and having to back down sucks. If you can, park the truck in a low spot, like a ditch, and put the end of the ramp on high ground. One area I ride in has a ditch that lets me put my ramps out almost level.
Also, try and have some kind of grip surface on the ramp – remember, you may be trying to maneuver a heavy bike, up a narrow strip, with wet and muddy boots and tires. Metal ramps usually come with a rough or studded finish. If your ramp is made of wood, you can add expanded steel mesh.
Here's a selection of aluminum truck ramps if you're looking for ease-of-use and looking slick at the track.
Pulling either requires a second person in the truck box pulling on a rope or strap tied to your handlebars, or a winch with a remote. To me, a winch to haul in your dirt bike seems like money better spent ON a dirt bike, but it's up to you.
The final option is manhandling your bike up into the box. If you're messing around with pit bikes, no problem. A 450? You better have a couple of real loyal friends with you.
Other transport vehicle options include cargo vans, or minivans with the back seats taken out. The positives include better protection for your dirt bike and a lower deck to load onto... negatives include a pervading gasoline smell that induces hallucinations or naps while driving.
Here's how NOT to transport your dirt bike on a vehicle.
TRANSPORTING ON TRAILERS
Another common motorcycle transport solution is a trailer. Again, you have some choices. A lot of dirt bikers are also snowmobilers, so they use their snowmobile trailer in summer. This requires adding some wheel chocks or a barrier at the front to put the front wheels against. Fastening is the same as for truck boxes as described above. Since this type of trailer has no sides, I'd also recommend something to keep the back end of your dirt bike(s) from moving around as you go over bumps. You can screw down blocks of wood for the season, spaced for the rear wheel to sit between, or use additional straps or ropes at the back of your bikes.
If you have a trailer with sides, simply treat it like a truck box. My favorite trailer for transporting a motorcycle is the landscape type. It sits fairly low, can carry three small to mid-size bikes, a little bit of gear, and they usually have a combination rear gate/ramp. During the summer, I back the entire trailer into my garage, loosen up the straps, and then I'm ready to go riding next time with only about 15 minutes of prep.
If you're using a trailer to transport a motorcycle or two, always make sure you have it locked securely to the hitch and – if your hitch isn't welded on – make sure the hitch is locked securely to your vehicle. I've heard about a trailer with two motorcycles being slipped out of it's “Hidden Hitch” receiver, trailer and hitch, and slipped into another vehicle's receiver and driven off... all because they saved $20 by not buying a locking hitch pin like the one below.
MOTORCYCLE TRANSPORT RACKS CARRIERS
If you only have one dirt bike to transport, a rack on the rear of your vehicle is a great solution. Most of these awesome dirt bike carriers mount to your vehicle using the existing receiver. Typically, you hook on the ramp supplied with the rack, roll your dirt bike onto the carrier, and then strap it down for transport. Better models let you store the ramp on the carrier itself, instead of your trunk or on the floor. Before you buy a carrier one, double-check the weight rating against the weight of your bike and load capacity of your vehicle. If your vehicle has a light duty suspension, you MAY have beef up the suspension to install the rack. For a quick and cheap test, calculate the weight of your bike and carrier, and load up the back of your vehicle with an equivalent amount of weight (bodybuilding weights, bricks, whatever).
Here's a link to a guy that built his own. Dirt Bike Carrier.
To wrap it up, remember how much money you have invested in your bike, and transport it with all the care and caution it deserves.