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Common Tread

Why you need to winterize your motorcycle, and why it’s easier than you think

Nov 12, 2020

I can already sense the scoffs and eye rolls coming from those of you who a) live somewhere warm and don’t need to winterize your motorcycles, or b) live somewhere cold but are such badass, SEAL-grade humans that you ride year-round, regardless of freezing temps.

Save your smugness for the comments section, because winter isn’t the only reason riders might park their bikes for an extended period of time. Maybe you’re shipping out for work, have surgery scheduled, or you have a prison sentence to serve. Whatever the rationale, there are steps you need to take to ensure your bike’s time off doesn’t render it unresponsive when you get paroled.

Safeguard your gasoline

When it comes down to it, there are only two things you really need to attend to in order to safeguard your motorcycle from trouble this winter. They are the gas in your tank and battery beneath your seat.

From a declining octane rating to the complete sludgification of your fuel system, gas is the biggest threat when it comes to long-term storage, and, depending on the conditions where you live, it could begin to go bad in as little as a month.

fuel stabilizer
Pour stabilizer into a full tank of fresh gas and it's protected for up to a year. How easy is that? Meanwhile, untreated gas can start to get funky in a matter of weeks. Photo by Spenser Robert.

Here’s what happens: The lighter molecules in the gasoline (including detonation-deterring octanes) evaporate, leaving behind thicker, heavier hydrocarbons. As the thinner stuff is flashing off, the fluid that remains oxidizes and thickens further. To make matters worse, most of today’s gas contains ethanol, which has the unique ability to draw moisture out of the air. It’s a cute trick, but when has water in your tank ever been a good thing?

If you have a carbureted bike, you can drain the carbs and tank and store it dry, but there’s no practical way to get all the gas out of a fuel-injected bike, so the best option is to do the opposite. Fill the tank (if you can find ethanol-free gas, that’s a plus) and add a quality fuel stabilizer, which will slow oxidation and help prevent ethanol from doing it’s thing for up to a year.

the effect of bad gas on carburetors
Yuck! This is not what you want to deal with when you get back to your motorcycle after it's been parked. For carbureted bikes, your best bet is to drain the carbs and tank completely. Photo by Ari Henning.

Stabilizer is the single most important thing you can do to protect your bike during long-term storage, and it’s as easy as pouring the recommended amount into a full tank of gas, sloshing it around to get it mixed thoroughly, and then running the bike to push the treated fuel through the system.

Adding stabilizer to a full tank is important since it reduces air space in the tank and keeps the bare metal submerged so it doesn’t rust. It also means you’ve got the bike’s full range at your disposal once it’s warm enough to ride again.

Not all devices are suitable for long-term battery care. On the left, an old-school constant-rate "trickle" charger. On the right, a modern "smart" charger that cycles on and off as needed. Photo by Spenser Robert.

Hook up your battery to life support

The next most likely thing to take a dump when your bike gets parked is the battery. Most motorcycles rely on lead-acid batteries, and they have the unfortunate tendency to self discharge when dormant. As the battery is bleeding off voltage, the cells are beginning to sprout lead sulfate crystals.

Sulfation is a normal part of the chemical process that turns lead, lead oxide, and sulphuric acid into electricity, but the crystals usually get dissolved once the bike is running and current is flowing into the battery. If your bike sits long enough, the sulfation may get so extensive that the battery can’t be revived.

Luckily, it’s easy to avoid an unresponsive starter button, a useless brick of hazardous waste, and the $100 cost of a new battery. Connecting the battery to a smart charger, also known as a maintainer, float charger, or tender, will keep it properly charged and keep sulfation at bay. And if you keep a lead attached to your battery, plugging in the tender is super easy.

Keep in mind, not all chargers are suitable for long-term storage. It’s important to use one that turns off once the battery is charged and only feeds current when needed. Old-school, constant-rate chargers and trickle chargers kick out a nonstop flow of electrons, so they’ll overcharge your cells if left plugged in. If that’s the kind of charger you have, you’re best off connecting it to the battery for a few hours once a month. If you don’t have power where you’re storing your bike, pull the battery out so you can take it inside and hook it up to life support.

Anatomy of a dead battery. Sulfation is normal, but it usually gets reversed when the bike is running and current is flowing back into the battery. Photo by Spenser Robert.

And, if your bike uses a modern li-ion battery, you’ve got it easy. The self-discharge rate of li-ion is so low that all you need to do is disconnect the negative battery terminal. No maintainer required.

In case you’re wondering, starting your bike regularly to “push fluids around and charge the battery” is not a good idea. For starters, startup is when your engine is most susceptible to wear (especially if it’s ultra cold), and running the bike introduces moisture (it’s a byproduct of combustion) to the engine oil and exhaust internals that’ll linger unless you run the bike long enough to get it up to operating temperature.

That’s it — unless you want extra credit

OK, so with just a few minutes’ effort you’ve safeguarded your gas and battery, and honestly, that’s all you really need to do to ensure your bike will start once the snow melts.

However. As good stewards of our motorcycles, there are a few more things we can do to keep our bikes well preserved during winter storage.

  • Give the bike a thorough bath to remove dirt, dead bugs, and corrosive crap. Follow that up with wax for the paint, a silicone detailer for plastic parts, and a light coat of WD-40 (applied to a rag and then wiped on) to chrome, polished, or anodized metal stuff to protect against corrosion.
  • Clean and lube your chain. Feel free to go heavy with the lube. The idea is to fully coat the links so they don’t rust.
  • Unless you like the idea of doodling designs in dust come spring, you’ll want to put your bike under a cover. An old bed sheet will do, but cotton tends to mildew and might attract rodents, so choose something that’s synthetic and breathable, so it won’t trap moisture.
  • If rodents are common in your area, it’s smart to seal your muffler and airbox. Some heavy plastic stretched over the openings and secured with a rubber band or zip tie will keep critters out as well as prevent moisture from wafting in and corroding your exhaust internals and the engine’s top-end parts. If you want to fog your cylinders, go for it. But it’s a PITA on most bikes and unnecessary unless you live near the ocean where the air is particularly moist and salty. You can also fog the inside of your gas tank to protect the metal from corrosion, if you choose to store it dry.
  • As for fluids, replace the coolant if it’s more than two years old to make sure you have adequate freeze and corrosion protection. And if your oil is more than halfway due for a change, go ahead and swap it out now. But, if the coolant and oil are relatively fresh, they’ll be fine for the winter.
  • Finally, your tires. Inflate ‘em and forget them! Seriously. Rather than fretting about flat spots this winter, transfer that concern to your tire pressures during the riding season, because the vast majority of people aren’t checking their pressures often enough, and rolling around on underinflated rubber is one of the worst things you can do for your bike’s handling and tire wear.

With all that covered, your bike should be in great shape for its winter nap. So to reiterate, drain or treat your fuel with a stabilizer and get your battery connected to a tender. Anything you do beyond that is extra credit and will help your bike get through its winter hibernation in better shape.