2009 450axi king quad. Rode it yesterday ice fishing, gassed it up on the way home. Went out to start this morning and the battery is dead. Did some electrical testing and came up with the following:

-Constant batter draw of 10 amps.
-Traced it back to the fuse labeled "fuel".

One dealer was no help and said 4-5 weeks to have them look at it (by then ice fishing will be over). Another dealer said that the year had some sending unit issues.

ANyone else experience this? Is it just a matter of replacing the sending unit with a newer year model?

 

Besides the fuel sensor assy you mentioned,what's it charging back to the battery while at an idle or a little above? If lower than 13 volts could be a regulator/rectifier burnt out.Item #5.Dirt Cheap Kawasaki & Suzuki OEM Parts & Accessories – Cycle Parts Outlet

 

The 450 fuel injection system is different to 500, 700 and 750 so replace any parts with ones from the 450. Can't remember if the 450 has a relay for the fuel pump, if it has it will probably be faulty. This isn't common, I work on them regularly and haven't had one go bad yet.

As for charging, they are a bit low, you are lucky if you get more than about 13.8v, this is due to longish thin wires from battery to regulator, a mod on 700s was to piggy back extra earth and "live" wires direct from battery to regulator, this pushed charging volts up to about 14.4. Charge the battery right away, these little ones die if left flat for a day or two.

 

Is it the original battery? If so maybe it just getting tired. The tops I expect out of a small recreational battery is 3years.
They are not made to last like a Automotive battery.

If its the original, a 6year old battery is passed beyond borrowed time. Might be time to head to Walmart with $50 and start fresh.
Bring the old one with you they will give you $10 for it.