You are here:

Motorcycle Repair/battery drain? and fuel pump?


So a few months back I left my ignition on on my Kawasaki zx636c1. I can out and tried to jump it off my car that was not running. The bike started but ran rough. I bought a new battery and after a a day and a half the battery was dead. I replaced the stator and rectifier and the relay box and the battery again and bought a battery tender. The bike charges within specs. I did notice that my fuel pump some times doesn't prime up when I turn the key on.but does eventually work after turn the key on and off a couple times. After it starts it works fine. Could this pump not priming up be a link to my two day battery drain? If the ecu shorted would that cause the battery to drain if shorted and the fuel pump to be temperamental? Please help. Thanks

Hi Zach,

What I would do is have the battery load tested to confirm it is not
losing stamina. Next, I would check to see if something is draining
the battery. Here is a general way to test for battery drain:

By pulling each fuse with a multimeter between the negative
battery termnial and the negative cable you can see which
circuit the drain is on.

A bad fuel pump or pump relay can cause eratic pump operation as can a
faulty ECU so that might be tough to solve.

I would start with finding the reason for the dead battery.
Something must be drawing power when the bike is off.

Do the drain test above and see if you can isolate the circuit the
drain is happening on.

That may tell you if it is on the ECU or some other circuit.

Once the drain is located then the fuel pump issue can be
resolved unless fixing the drain issue helps.

It might be a short somewhere or a bad component.

ECU is usually the last resort but you can check the
connectors and wiring for problems.

Wayne S

Motorcycle Repair

All Answers

Answers by Expert:

Ask Experts


Wayne S.


Licensed Motorcycle Mechanic, Knowledge of motorcycles from 1960 up, Japanese, British and most other brand motorcycle repairs.


Worked for Yamaha, Honda, Suzuki, Kawasaki British: Triumph, Norton, BSA Other: Most Scooters and Mo-Peds

Canadian Motorcycling magazine article

Licensed Motorcycle Mechanic

©2017 All rights reserved.