The KTM 450SXF Factory Edition is a blast to ride.

Dear MXA,
    As I sit waiting for my KTM Factory Edition to arrive at my local dealership, I am reading horror stories on the web about how the battery goes dead and can’t be charged with a normal battery charger. Also, I heard that the 450SXF Factory Edition is hard to start. Is this true?

We are more than a little surprised that a dealer would sell a bike to a paying customer without making sure that the battery was charged before letting it leave his shop. But, if the LiFePO4 (lithium-iron phosphate) battery does get run down it cannot be charged by a conventional battery charge at full-power. Note that we said “full power.” However, you can use any automotive battery charger or trickle charger that has smart meter to limit the output to less than 2 amps. Just don’t let a 2 amp battery charger stay on the KTM battery after it is fully charged. KTM sells two different battery chargers (a trickle charger and a more complex charger/tester) that will work with KTM’s Samsung LiFePO4 battery. Charging time is around 8 hours. MXA has had its 250SXF and 450SXF for a reasonably long time and we have not had any battery issues. Because of the lack of sulfation and slow-self discharge of lithium-iron phosphate batteries, once a LiFePO4 battery is charged, it holds that charge longer than a comparable lead-acid battery. We have had LiFePO4 batteries sitting on a shelf for more than a year and when put in a bike, they are still at full charge—not so with lead-acid batteries

The lithium-iron phosphate battery is on the left, while last year’s lead-acid battery is on the right.

Don’t confuse a lithium-iron phosphate battery with a lithium-ion battery (more specifically, a lithium cobalt-oxide battery). The more expensive Lithium-ion batteries are most commonly used in computers, cameras and phones. A lithium-iron phosphate battery (liFePO4) has a higher resistance to thermal runaway, longer calendar life, quick recharge rate, five times as many available discharge cycles, a higher peak-power rating and costs less. LiFePO4 batteries contain no poisonous lead, no acid and do not create gases during charge (as traditional lead-acid batteries do). There are no liquids in an LiFePO4 battery, which means that nothing can leak, and you could put it in your bike upside down if you wanted to. Compared to a lead-acid battery, lithium-iron phosphate batteries are lighter and deliver a more powerful punch to the starting system.

KTM had to reconfigure the battery tray for the new Factory Edition subframe. The full pump connector is on the far left, the black box is in the middle and the battery is on the right.

That said, we did have troubles starting our 450SXF Factory Edition when it was cold outside. But, there is a solution. Since a LiFePO4 battery gains amperage and spins the engine faster as it warms up, we preheat the KTM’s battery before we try to start the bike on a cold morning. How do we do that? First, we press the starter button, but not enough to start the bike, but enough to make the fuel pump run (which puts a load on the battery). You can hear the fuel pump click over or you can place your hand on the gas tank and feel the vibrations of the fuel pump. By activating the battery, the lithium-iron phosphate battery will get stronger as it gets warmer. Second, we reach under the throttle body and push the yellow dial upwards. This is the cold start button, and while most cold and hot start buttons are pulled out to engage them, the Factory Edition’s is pushed in. Now, push the starter button enough to start the engine. Don’t overdo it. We suspect that some of the reported dead batteries have been caused riders grinding away with the starter motor until the battery goes dead. Take our word for it, if the bike doesn’t start in a short period of time—stop and move on to the next step.

If the temperatures are under 50 degrees, you should preheat the battery three times, waiting 5 to 10 seconds before lightly pressing the starter button again. Obviously as it gets colder, you may have to preheat the battery even more times. As the battery gets warmer the voltage goes up. As a rule of thumb, all batteries have to work harder in cold weather regardless of their chemistry

See the yellow dial under KTM’s 44mm throttle body. You push it in until it clicks to start your bike in cold weather. You can push it even further if you have to.

We have another solution for a hard starting bike. We reach under the throttle body again, only this time we use our left hand to push the yellow dial upwards even further (it is spring loaded) and we hold it there while we hit the starter button with our right hand. Voila. The bike should start. You will not need to do this trick after the first time the bike starts and in warm weather you should never need to press the yellow dial. But, the colder the morning the harder the bike will be to start the first time.


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