done some diagnosis just want more learned opinion

My kz1000 police bike was running great then suddenly the starter motor won't turn.
Can jump start it.
Took out the mulitimeter and battery reads 12.4v - so all good.
turn on key and battery still reads 12.2v - so all good.
try the starter motor, no luck, and battery reads 3.9 - battery gone?

Been trying to do a lot of reading about electrics and I've read that if you engage the starter and the battery falls below 9v it means one of the cells in the battery is bad and you should just just junk the battery.
Obviously a heads up on this diagnosis would be mucho appreciated before I go spending my hard earned cash on a new battery - especially seeing as I've only had the bike for 2 weeks! :S

It's possible the brushes(the carbon pieces that rub against the motor's commutator) have worn out, but try this troubleshooting procedure:

Starter Solenoid/Motor Checkout Procedure

Some simple steps to determine what is working and what's not:

1.Fully charge and test the battery(most bike shops can load test the battery, and then use a floating ball hydrometer to check specific gravity in the charged cells).

2.Clean all battery terminals of corrosion.

3.Tighten all starting related connections(Positive RED(+) battery terminal, Negative BLACK(-)terminal) and from the terminal to the engine case. All connections must be clean and tight. If the cables feel “Crunchy” when flexed, they may have corrosion inside the insulation, requiring replacement.

4.Clean the cable from the starter solenoid to the starter motor.

5.Clean and check the "bullet connectors" going to the coil side of the starter solenoid.

6.Try again to start the bike, keep in mind some Kawasaki’s have a clutch interlock to prevent cranking the engine while it’s in gear, so the clutch lever must be squeezed.

7.If no luck, go to step #8

8.Wearing eye protection, bridge with pliers or a screwdriver the two heavy duty(large)terminals on the solenoid. If the bike cranks, your solenoid may be bad.

9. If the starter won’t turn over, one of several things has happened; The starter motor has seized due to brushes binding up or worn out, lack of lubrication in the bushings of the motor, the battery is weak , the engine has seized or it could be a combination of any of the above. A website for starter motors is:

A. www.psep.biz/store/mitsuba_starter_motors_page_2.htm

B. www.nationsautoelectric.com/Kawasaki.html

C. www.whitedogbikes.com/cat--Kawasaki-Star...-Starter-Motors.html

D. www.ricksmotorsportelectrics.com/starters.php

10.The dealer may want $$$ for a new solenoid, but take your old one along and visit the nearest riding lawn mower shop. They have solenoids for about $15 that with a little work will fit. Be aware that the new solenoid from the lawn mower shop may require a ground wire for it to work.

11. I’d recommend upgrading from the existing battery cables to at least 6 gauge welding cables.
They are available in two colors(RED and BLACK) have more flexibility due to being constructed with finer conductors, and will fit in tighter areas.

12. The welding cable is sold by the foot, so take careful measurements or bring your old cables along. Most battery shops might be able to supply the cable too, so call to find out. The battery shop should be able to crimp/swage on the end of the welding cable the terminal ends or lugs using either a dedicated crimping machine or a tool that looks like a bolt cutter that has special dies to terminate the cable.

Would service the battery, charge it overnight, and then repeat efforts to crank over the engine, or have the battery load-tested.

Most battery suppliers will perform a load-test free of charge.
After charging the battery overnight, would have it load-tested before putting any load on the freshly charged battery.

Good Fortune!

strang wrote: My kz1000 police bike was running great then suddenly the starter motor won't turn.
Can jump start it.
Took out the mulitimeter and battery reads 12.4v - so all good.
turn on key and battery still reads 12.2v - so all good.
try the starter motor, no luck, and battery reads 3.9 - battery gone?

Probability is VERY high it's a bad battery. But, add water, charge up, check all terminal connections before writing it off. Bike batteries live short, unhappy lives because they are undersized and overdrawn. :laugh:

Yep was the battery - got it checked by local shop and they said it was gone. Was slightly skeptical though as surely it is in their interests to say the batterie is dead? Anyway thought I'd trust them and order a battery through them for their help. After 2 weeks of them saying they couldn't get a battery from their supplier for the bike, I spent 7mins online and ordered one to my door. Shops say they are being put out of business by the internet but I think half the time it is because they offer poor customer service!

Popped battery in (actually wasn't that easy as wires are all over the place and battery was bigger than the last one) and after a bit of cranking that was probably a combination of old petrol and the cold weather - bbbbbrrrrrrrrrrrrrr - I'm on the road again. Thanks people. Me learning.

next up - going thru the 30 years of wiring bodges I saw around the battery : (

When doing wiring repair, I use these splices/butt connectors and heatshrink tubing:

this is great info - many thanks MFolks!

Just wish those amazing sealed solder connectors were available in the uk.

You motorcycle freaks got it lucky in so many ways on the other side of the pond.

I'd contact the manufacturers and see if distributors can be set up in the UK. I see no reason not to have the same type of connections we have on this side of the pond....

In case I can't get a supplier over here - where do you buy these over in the states? The companies mentioned in the youtube clips seem to be wholesalers.

For the crimp and then heat splices(sometimes called butt connectors) 3M is one supplier found at most auto parts stores I'd imagine over there, any good electronic supplier could get the soldered type as aviation repair shops use them here, and I'd imagine over there too.

Check into Mil-Spec wire harness(loom) fabricators there as they have sources.