The prime tire for winter riding – if you can afford it – is one with the spikes permanently installed. If you can, get the carbide-tipped spikes – they'll last much longer, giving you more riding for your dirt bike buck. Speaking of price – it'll seem a little steep at first, but sit back and realize that they'll last for years, and then think about how much it's worth to get all that extra dirt bike time.
If you just can't afford the ready-made tires for riding in the snow, or on ice, you still have a homemade option. Visit your local hardware store or building centre and pick up a bag of hex-head metal screws. If you're okay with spending a little bit more, check your local dirt bike shop, or online, for ice riding screws or tire traction screws. As I mentioned, they're a little more expensive than the hardware store option, but tend to stay in the tire longer and grip a little better.
When you're making your own set of winter or ice tires for your dirt bike, it's going to feel a little strange screwing a sharp object into your tire on purpose. Ideally, you want to install as long a screw as possible so it stays put... but not so long that it punctures your inner tube. If you can, use newer or brand new tires since the knobs will be taller/thicker and try not to use screws shorter than half an inch.
If riding your dirt bike in the snow turns out to be a regular and frequent event, keep your eyes open for an extra set of rims for your machine. If you have your winter tires pre-mounted on rims, swapping tires can be done in less than an hour.
If you're going to ride your dirt bike in the snow for more than a few minutes, you'll want to install a shield or protector for the carburetor – otherwise your carb will ice up, and your dirt bike's performance will suffer. If you look around long enough, you can find commercially made shields for some bike models, but a homemade solution is fairly easy to come by. I've seen protectors made from cutting plastic bottles or milk jugs to shape... inner tube pieces zip-tied to the carburetor... and a modified hand guard complete with its own mounting screws. Avoid using any kind of tape to hold the shield in place – it'll often lose its grip in cold and/or wet conditions, and any fuel and oil drips will loosen up the adhesive. The carb area is also an awkward place to clean tape goop out of.
If you're going to ride your dirt bike in the snow for more than a few minutes, you'll want to install a shield or protector for the carburetor – otherwise your carb will ice up, and your dirt bike's performance will suffer. If you look around long enough, you can find commercially made shields for some bike models, but a homemade solution is fairly easy to come by. I've seen protectors made from cutting plastic bottles or milk jugs to shape... inner tube pieces zip-tied to the carburetor... and a modified hand guard complete with its own mounting screws. Avoid using any kind of tape to hold the shield in place – it'll often lose its grip in cold and/or wet conditions, and any fuel and oil drips will loosen up the adhesive. The carb area is also an awkward place to clean tape goop out of.
Also, depending on your bike and the day's conditions, keep an eye on your air box to make sure you're not sucking in snow and plugging it up.
I mentioned heated grips in the clothing article, but forgot another quick tip. If you have access to the right size shrink tubing, put some on your clutch and brake levers. A double-layer is even better if you can manage it. This will help insulate your fingers from the heat-sucking metal on the levers. In the summer, if the shrink tubing bothers you, it's easily removed with one slit along the length of the lever. A few layers of electrical tape can help if you don't use the shrink tubing, but it's harder and messier to remove in the spring.
I mentioned heated grips in the clothing article, but forgot another quick tip. If you have access to the right size shrink tubing, put some on your clutch and brake levers. A double-layer is even better if you can manage it. This will help insulate your fingers from the heat-sucking metal on the levers. In the summer, if the shrink tubing bothers you, it's easily removed with one slit along the length of the lever. A few layers of electrical tape can help if you don't use the shrink tubing, but it's harder and messier to remove in the spring.