Tech Talk: Winterizing Your Motorcycle; Batteries 101

Winterizing Your Motorcycle

Even before the frost is on the pumpkin, many of us have said goodbye to the riding season for the year.  For the lucky few riders south of the Mason Dixie Line, tolerable riding weather extends well into the holiday season.  As for the lucky few with a 12 month riding season, this is where you get off, as this post has no relevance to your riding at all.

Kick Start vs Electric

Unless you are an old school biker and purist, the process of starting up your motorcycle begins only with the push of a button. All of you bent knee folks out there, I apologize.

On this ’09 Harley Ultra Classic the Motor Company does not make life easy here either. The battery is located UNDER the ECM module. You can see the pigtail attached as is indicated by the arrows in the photo.

To Remove, or Not Remove

Most service manuals from different manufacturers will say to remove your battery from your bike and store it fully charged for the winter. They of course make this statement as though they have been dedicated to making even that simple task easy. As you will see from the accompanying photos, that is decidedly NOT the case.

The seat is off, but where is the battery on this Honda ST1000?

The pressing of that starter button requires a fully charged 12 volt battery. In this article I am not going to delve into the host of physics, electronics or mechanics to make your motorcycle come to life. Suffice it to say that an ounce of prevention is definitely worth a pound of cure when it comes to batteries.

With the increasing use of electronic gadgets, memory, ECM’s and the like there will always be some parasitic loss of charge from the battery to these circuits with the battery

Hidden under another panel you must remove with a properly sized hex wrench is the battery on the Honda,

installed in your bike. A battery at less than full snuff will create a lot of headaches.

Regardless of make, most current day motorcycles use an AGM or “Absorbed Glass Mat” battery to provide the juice to turn over your engine. Though this is still a lead-acid battery, the internals of the battery and case eliminate the need for checking water levels or even keeping the battery fully upright. AGM batteries are rugged, dependable, reasonably priced and long lasting with proper care. Unlike the old flooded wet cell lead acid battery though these energy storage systems are far less forgiving of letting them run down to a discharge state. In fact, if an AGM battery discharges to the point of you just hearing a click at the starter, you need a whole lot of very expensive charging equipment to

Battery Tenders come in a wide variety of styles and price ranges

resurrect that poor soul so that it will again be dependable when you hit that starter button. Yeah, you might throw a run of the mill charger on the battery and the engine will start. But park it outside for one night and then go hit the starter and “click-click-click”. I have had AGM batteries last me for over 7 years, and I am going to give you the inside scoop on how to make that happen for you as well.

Compounding the problem of battery maintenance is the fact that almost all manufacturers now BURY the battery UNDER a lot of other stuff as though you are never going to have to get to it. Of course with proper maintenance, the battery will be one of your least concerns. To get to many of the batteries on Harley, BMW, Honda, Suzuki, Star, etc. you will likely need a service manual and some tools to even gain

These are the parts that had to be removed and the tools needed to get to the battery on the Honda.

access to the battery.

The Basics

1)      Good Connections: All batteries can produce corrosion at the terminals. AGM’s are no exception; however, this white cancer is far less of a problem than with the old flooded cells. Make sure the positive + and negative terminals of the battery are bright and clean. The negative cable needs to be traced to either the frame or starter motor to be certain that end of the connection is clean and tight too. These contraptions vibrate you know.

2)      Protection: Once the terminals at the battery are clean, invest a couple of bucks in a battery terminal protection spray, available at any auto parts store.

3)      Parasitic loses: Even switched off all motorcycles with an ECM (Electronic Control Module) and

Cheapest corrosion protection insurance you can buy

certainly those with radios and clocks use some current supplied by the battery to keep their memory maintained. Over time this unattended loss will kill all batteries.

4)      Maintain: It is good practice to invest in a multi-stage maintenance charger that keeps the innards of the battery as good as new. Companies like Deltran’s® “Battery Tender” (Jr., Plus, or multibank) or VDC Electronics® Battery Minder Plus have great products for just this application. They can be hooked up indefinitely. They are all the type of charger that AGM batteries love. Now instead of wasting time removing and then reinstalling a battery in your bike, you can just leave it in the bike and via supplied connectors from the aforementioned companies you will have an SAE type pigtail to plug into.

5)      Pigtail: Most Harley’s come from the factory with a 2 prong SAE type connector. See photos. You may have to look a bit because it seems on every model they zip tie it to a different location on the bike. For my ’09 Ultra Classic, I found it attached to a frame member way down near the transmission. Metric bikes usually will require that you install this pigtail onto the battery. There is really a proper engineering term for this pigtail, but for us plain folks, pigtail gets the message across.

6)      Accessorize: Since the pigtail connects directly to the battery and contains its own fuse you can also use this connection to power any number of devices like a GPS, or my favorite, heated clothing. All of the companies will have some adapter to allow you to plug into this Pigtail directly.

7)      Charging System: Without getting too technical, and because all systems are different, you can

Digital Multimeter set to appropriate DC voltage range and sample readout from a fully charged 12 battery. Yes…they should read over 12 volts.

check whether your charging system is actually delivering voltage back to the battery with one simple and inexpensive little tool. A digital multimeter is what I am talking about here. See the photos if you don’t know what this is. Set the dial to DC volts and then follow this process:

a)      Before starting your bike touch the red lead to the positive battery post and the black lead to the negative battery post. Simply make a note of this number on the readout, it will be different for almost every battery. The exact number is not really important for this test.

b)      Start your bike and then do the same thing with the leads of the multimeter, red lead to positive battery post and black lead to negative battery post. Now just rev your engine to about 2000 RPM. The voltage should be higher than your reading you got with the bike engine not running. If the voltage is lower, then your charging system (stator, rotor, connector, regulator, etc) may have some problem and deserves additional attention from a qualified service technician.

c)      Wa-la! You have now done a rudimentary test of your charging system and if you know what the battery voltages should be from your service manual, you even have some degree of confidence about the battery health.

There are volumes that may be written covering all sorts of ills, but these simple steps for 99.9% of riders will assure that when the thumb presses the “start” button, the beast will spring to life.

Engine Oil

If you have not changed your engine oil at this stage of the game, do it now. You do not want a bike that has oil from the riding season sitting inside the engine for extended periods of time. Why? All oils have additives that work to keep the ph level at a certain point. This is called TBN or “Total Base Number”. Acids from combustion build up and are neutralized by this TBN additive. Acids are not good for any part of the inside of a motor. TBN decreases over time. Depending on mileage you could forego the primary and transmission changes at this point for those bikes that have these separate fluids. These areas do not have combustion processes involved.


Also keep your gas tank filled and put in some gasoline stabilizer while filling. This is a good practice even during the riding season. Current ethanol blends of gasoline are horrible. Ethanol is hydroscopic, hygroscopic, that is, it attracts water. The current blend of gasolines also will undergo what is called “phase separation” in as short as 30 days. If these things happen, not one bit of your warranty from any manufacturer will cover the issues caused by this fuel problem, unless you have a very sympathetic and creative mechanic who does the paperwork.

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  9. Great article. BTW, the term that describes attraction to water is “hygroscopic.” I know that’s not intuitive, but that’s the English language for you.

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