Most people understand that vehicles need a battery to function; a battery is an essential part to the starting process. Without it, you wouldn’t be able to get anywhere because the vehicle wouldn’t be able to turn over in the first place.
Because motorcycles are smaller and a little more simple than most other vehicles, some may wonder if motorcycles may be an exception to the battery rule.
Can a motorcycle run without a battery? It is possible for a motorcycle to start and run without a battery, especially smaller motorcycles that are 250 CC’s or less and have a kick starter. The bigger the engine, the less likely the motorcycle will be able to start without a battery. Some proper rewiring is required in order for this to work.
It may seem odd that a motorcycle could possibly run without a battery since most of us know how vital a battery is to a vehicle’s function. Through my automotive experience, I’ve been able to see how and what it’s like running a motorcycle without a battery.
Starting A Motorcycle Without A Battery
The first time I heard about starting a motorcycle without a battery, I was a bit in disbelief. I’m a gear head and have been heavily involved with cars since before I was a teenager, so I knew how cars worked. But I wasn’t too familiar with motorcycles before I really started getting into them when I went to college.
Since then, I’ve restored over a dozen motorcycles and worked on dozens of others. I quickly realized that while motorcycles do have the same basic components as cars, they hold a lot of exceptions including starting one without a battery.
There can be a lot of answers to whether or not a motorcycle can run without a battery. The broad answer to that is it depends, especially on the type of motorcycle, whether it has a capacitor, etc. But as a general and more specific answer, it is completely possible to get a motorcycle started without a battery, especially if it is a smaller motorcycle.
It’s easier to start a kick start motorcycle that has a small displacement engine, such as 250 CC’s or smaller. If a smaller motorcycle like this has a kick starter, you can usually get enough compression from the engine to help start the motorcycle without the power from the battery.
You will need to do some rewiring beforehand in order for this to work. Though there may be some compression left over to start the engine, you still need an electrical component to fully get it started, so you’ll need to reroute the wires directly to the stator to get that power once the battery is removed or surpassed. If you wish to also run the head lights, blinkers, tail light, etc., you will also need to reroute those and connect them to the stator as well.
You will not be able to start a motorcycle without rewiring the electrical components and connecting to the stator. The ignition coil needs electrical power from somewhere and if it isn’t getting it from the battery, it needs to come from the stator. Though the stator may not give as much current to start the motorcycle, the mix between the power that’s left within the stator and the compression inside the engine should be able to get the motorcycle started on smaller bikes.
It is possible to do this technique on bigger motorcycles that have a kick starter, but the bigger the bike is, the less likely it will be able to start. Bigger engines on bigger motorcycles means they require more power to start and the more cylinders there are that you’re fighting against. You won’t have enough power to kick start a bigger engine with left over power in the stator and compression in the engine.
Running A Motorcycle Without A Battery (After You’ve Started It)
There’s actually a little bit of a difference between getting a motorcycle started without a battery and running a motorcycle without a battery by disconnecting after getting it started. Getting a motorcycle started takes a lot more effort compared to just running it.
The next biggest question people will have is if you get the motorcycle started using the battery and get it running, can you disconnect the battery and have the motorcycle keep running? The answer is yes you can keep the motorcycle running if you remove the battery after you get it started.
This holds true not only for motorcycles, but for pretty much any other vehicle in the world. The battery is what is used to get the vehicle started and the alternator (or the stator for the motorcycle) is what keeps the vehicle running. The battery holds no meaning during the running process unless the alternator is bad.
If you are stuck somewhere with a dead battery, it’s possible to borrow someone else’s battery to simply get the motorcycle started, remove the battery, then get yourself safely home. You cannot turn the motorcycle off during that time because you won’t be able to turn it back on.
It’s also possible to jump start a motorcycle without a battery. All you need to do is connect the jumper cables to the positive and negative terminal wires and the motorcycle will run until you turn it off.
Is It Bad To Run A Motorcycle Without A Battery?
There are a lot of alterations you can do to a motorcycle and still make it functional. But if you are planning on starting and/or running your motorcycle without using the battery, there are a few things you should consider while doing so.
While it is very possible to run a motorcycle without it’s battery, it’s not advised that you do it. Starting and running a motorcycle without a battery doesn’t necessarily hurt the motorcycle, but it can be a safety hazard for you as the rider.
Most people are unfamiliar with how to rewire and handle electrical components on a motorcycle. Though the wiring harness isn’t as complicated as most vehicles, it’s still a difficult component to understand, especially if you’ve never dealt with it before.
Because of people’s lack of understanding of wiring, most people don’t properly rewire and end up tying the ends together and cover it with electrical tape, calling it good. This is the cheapest and least effective way to rewire and should never be practiced.
Dealing with the wiring that’s coming from the ignition coil also holds it’s own dangers; the extra current could possibly find it’s way through the wire and into your fingers if the battery is still plugged in.
If all the wiring was connected to the stator, that means all your lights will only work when the motorcycle is on. The more power you give the motorcycle, the brighter the lights will be. If you have to go slow during the night, your headlight may not give you enough light to see adequately. To learn more about how a battery impacts a motorcycle’s performance, see our other article by clicking here.
Having a battery on your motorcycle is simply superior in every way. There is no reason a battery should be removed from a motorcycle unless the rider is in an emergency situation. The rider should then get a battery as soon as possible.
How To Make Your Motorcycle Look Like It Doesn’t Have A Battery
The biggest reason people try to eliminate the battery altogether on their motorcycle is for cosmetic reasons. Batteries can really be an eye sore if placed on the motorcycle the wrong way, but that doesn’t mean you have to take it out of the picture altogether.
I turned most of my motorcycle restorations into cafe racers. Cafe racers are minimalist bikes which means I often had to get creative with where to hide the battery. I was able to come up with several ways to make the motorcycle look like it didn’t have a battery at all.
Some of the places you can hide the battery are laying it on it’s side on the rear swing arm, mounting it under the rear swing arm, mounting it under the seat in a battery box, or putting it where the airbox was. For more information about how to hide your motorcycle battery, see my other article here.
Another option you have when giving your motorcycle the battery-less look is using a lithium-ion battery. These batteries are much smaller than regular motorcycle batteries and it can be easy to place them almost anywhere on your bike without being seen.
Can a motorcycle that doesn’t have a kick start run without a battery?A non-kick start motorcycle most likely will not be able to start without a battery, even after you rewire the ignition coil to the stator. Without adding the compression of the engine activated by the kick starter, there won’t be enough power to start it in the first place.
How long can a motorcycle sit before the battery dies? The average motorcycle battery will die after 2 – 4 months without running. Newer batteries can last longer with an average of 3 – 5 months until dying whereas older batteries will last about 1 – 3 months until the battery dies while the motorcycle is sitting. See my article here for more information.