Weird starting problem 83 KZ750 L3, need help!

I have an 83 KZ750 L3 that starts fine when cold, runs well until I shut it off. Then when I try to start it, it turns over slowly a couple of times, not nearly fast enough to start the engine. I can jump start it but the electric start won't work for 20 minutes to an hour later. I've rebuilt the starter, changed the voltage regulator. Charging voltage is fine, battery has been replaced. Basically the mechanic at our local shop, Burnaby Kawasaki, doesn't have a clue and neither do I. Any help or ideas would be appreciated. Thanks!
Rod

Let's go the simple route first before getting into more expensive repairs.

Is the battery in good shape? Checked the battery under load?(most auto parts stores can load test bike batteries).
Are you sure the new battery is good?

Battery terminals clean and tight? No corrosion? Battery cables from the RED Positive(+) terminal go first to the starter solenoid and then to the starter motor, all must be clean and tight.

The BLACK Negative(-)terminal goes to an engine mounting bolt, and must be clean and tight.

Post back if the battery connections are good.

MFolks wrote:

Let's go the simple route first before getting into more expensive repairs.

Is the battery in good shape? Checked the battery under load?(most auto parts stores can load test bike batteries).
Are you sure the new battery is good?

Battery terminals clean and tight? No corrosion? Battery cables from the RED Positive(+) terminal go first to the starter solenoid and then to the starter motor, all must be clean and tight.

The BLACK Negative(-)terminal goes to an engine mounting bolt, and must be clean and tight.

Post back if the battery connections are good.

X2 on the above.

Check for voltage drops, heat increases resistance.

Another thought:

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.

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, 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. Some websites for starter motor rebuild kits are:

A. www.mawonline.com/newsite/rick_s_motorsp...-starter_brushes.htm

B. www.cyclewareables.com/pages/street_star...kits/startmtrkit.htm (not sure if the website is still viable)

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


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.

kz750l3 wrote:

I have an 83 KZ750 L3 that starts fine when cold, runs well until I shut it off. Then when I try to start it, it turns over slowly a couple of times, not nearly fast enough to start the engine. I can jump start it but the electric start won't work for 20 minutes to an hour later. I've rebuilt the starter, changed the voltage regulator. Charging voltage is fine, battery has been replaced. Basically the mechanic at our local shop, Burnaby Kawasaki, doesn't have a clue and neither do I. Any help or ideas would be appreciated. Thanks!
Rod

Rod,

I just sat down to start a thread on this topic for my 1981 KZ1100A1 and saw your post. It sounds like I have the same problem - my starter turns the engine over fine when it's cold but after the engine is warm it turns over very slowly and stops momentarily after each turn. I think the problem has to be something that is OK when the engine is cold but not when it's hot.
- I don't think it's the battery. I have a fairly new Odyssey and a Battery Bug voltage meter that shows 12.7 volts and "Battery 100%" before I start it cold or hot, and the stator puts out 13-14 some volts when it's running. I can let it sit for a week or two and it will crank just fine and start, but after riding it has a problem.
- It doesn't seem that the starter relay can be the problem because if the starter turns over at all the relay must be closed. Also, it doesn't seem like the relay would get hot from riding. Someone on the forum may know the answer to this. I'll try to check this out tomorrow.
- It doesn't seem like it can be the battery cables for the same reason.

I'm hoping someone on the forum has run across this exact problem - the starter works fine when cold but not when hot (after riding?). I've had the starter clutch apart and I can't see how it could work differently when hot than when cold.

I had this problem. Here is what I believe is happening: When cold, the bike turns over easily, but when it is hot, the clearances in the engine (piston/rings/cylinders) are tighter, and thus create more resistance. Thus, if the battery, starter, or any electrical connections or switches are weak, the bike just cannot turn over fast enough.

In my case, I cleaned up all the connections, and the contacts in the starter solenoid, and replaced an old battery. I have never had a problem since.

Use jumper cables and a car battery to power the starter directly, negative to the motor cases and positive to the battery stud on the starter, and do it when hot. If the motor spins over fine, then the problem is in the wiring/relays somewhere, if the motor just barely (or not at all) cranks over, then either replace the starter or replace the starter bushings on each end of the armature.

What happens is the bushings get worn, and then they expand even more with heat, and they expand far enough to let the armature drag against the windings when hot, so the starter drags.

Use jumper cables and a car battery to power the starter directly, negative to the motor cases and positive to the battery stud on the starter, and do it when hot...

Car OFF. Car keys in pocket. just in case...

Hi Guys, Thanks for all the replys. The mechanic at burnaby Kawi has rebuilt the starter twice. He says that the brushes and other housing parts were worn out. So it is working for now, turns over way more easily. It still seems like it it is less powerfull after it's run for an hour or so but so far it hasn't refused to start. I guess more will be revealed as time goes on. Thanks again..

Try rebuilding your starter, it's working so far for me.

I know I'm way late on this, but I had a voltage leak through my head lights on the same bike. I'd charge it up at home, and it'd start like a champ. I'd ride it for a day at highway speed and have to charge it again at night.

It was the reserve lighting device. I had a mechanic wire around the damn thing and then everything ran great from then on. He even said my charging system was perfect.

It doesn't sound like the same problem, but I thought I'd throw it out there, even ten months late.