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1996 GSXR 750
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So might just be the starter? I was thinking about replacing that next. Have replaced the rectifier, battery and stator but it’s still the same. How can you test the starter? Thanks in advance
I'm not aware of any easy way of testing the starter. But it can be easily removed and opened up to inspect internals - damage might be obvious once you inspect the windings and magnets. But before you do this, I suggest you do the same test I did, i.e. try to start the bike hot and then keep trying as it cools down. If the bike won't crank properly when hot but then cranks fine when cold, you don't have a battery or charging system problem. You have something causing increased load (which needs increased amperage from the battery) when the bike is hot. Once started, if the bike runs fine, then the increased load must be from something in the starting circuit. The starter would be the first place to check.
 

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I'm not aware of any easy way of testing the starter.
Just check battery voltage when running, with and without starter wires connected.

I mean, if you measure over 14V when running before disconnecting it, then there is no reason to disconnect it, it's the battery!

Ah, that amazing instrument called 'a voltmeter'. I'm surprised how many people try to fix electrical problems without one. I tried to persuade someone to get one a while ago for a car fault, and they insisted on getting a bluetooth OBD dongle so their phone could tell them the battery voltage.

Is it a 'Gen Z' thing? Grandpa's tech is old hat, let's throw away the multimeters?
 

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What did Einstein say about doing the same thing and expecting a different result? LOL
That was before 'Windows' and computer operating systems. If something doesn't work, turn it off and back on again. If it still doesn't work, wait 10 minutes then do that again.

Computers have, by Einsteinian philosophy, turned us into idiots.
 

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I'm not aware of any easy way of testing the starter.
Just check battery voltage when running, with and without starter wires connected.

I mean, if you measure over 14V when running before disconnecting it, then there is no reason to disconnect it, it's the battery!
Checking the battery voltage with the bike running is not a test for the starter. When the bike is running, the starter circuit is open (no current), unless someone pushes the starter button (which is a stupid thing to do if the bike is already running). So the battery voltage will be the same whether the starter is connected or not.

My comments above are based on my experience with my old SRAD. The starter was drawing excessively high amps when the bike was hot. So high that the engine barely cranked over - it behaved like it had a weak battery. But once cooled down, the same battery would crank over the engine freely. This is what prompted my to look at the starter. The only way I can think of for testing the starter for excessive amperage draw, is to connect an ammeter to the starter circuit. But the amps will be higher than what a standard bench voltmeter can handle (it will blow the voltmeter fuse, or fry the unit). There are better quality industrial ammeters on the market, but they are more pricey and most people don't have one.
 

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Checking the battery voltage with the bike running is not a test for the starter. When the bike is running, the starter circuit is open (no current), unless someone pushes the starter button (which is a stupid thing to do if the bike is already running). So the battery voltage will be the same whether the starter is connected or not.

My comments above are based on my experience with my old SRAD. The starter was drawing excessively high amps when the bike was hot. So high that the engine barely cranked over - it behaved like it had a weak battery. But once cooled down, the same battery would crank over the engine freely. This is what prompted my to look at the starter. The only way I can think of for testing the starter for excessive amperage draw, is to connect an ammeter to the starter circuit. But the amps will be higher than what a standard bench voltmeter can handle (it will blow the voltmeter fuse, or fry the unit). There are better quality industrial ammeters on the market, but they are more pricey and most people don't have one.
I didn't think that was the OP's issue, they seem to be reporting that each successive use of the bike means the cranking is less and less. Maybe I did not understand the exact problem.

A bike in good condition should start inside one crank, if not less, so whether the starter is using up too much energy is secondary to why the bike isn't starting on the crank. Fix that, then it's immaterial if the starter is using twice the juice it should be.

Maybe I am still misunderstanding? Until we have some voltage readings, it's all guesswork, not really the way I like to do engineering.
 

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A bike in good condition should start inside one crank, if not less, so whether the starter is using up too much energy is secondary to why the bike isn't starting on the crank. Fix that, then it's immaterial if the starter is using twice the juice it should be.
I agree. If the bike starts is difficult it would be a reason of this issue.
 

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I didn't think that was the OP's issue, they seem to be reporting that each successive use of the bike means the cranking is less and less. Maybe I did not understand the exact problem.

A bike in good condition should start inside one crank, if not less, so whether the starter is using up too much energy is secondary to why the bike isn't starting on the crank. Fix that, then it's immaterial if the starter is using twice the juice it should be.

Maybe I am still misunderstanding? Until we have some voltage readings, it's all guesswork, not really the way I like to do engineering.
The engine won't start if the engine is not turning over fast enough - that's my point. It may not be the OP's problem, but the symtoms seem similar to what I've had on my bike. When trying to start my bike when it was hot, the engine would not turn fast enought to start, if it turned at all. But on a cold start, the engine would turn over freely and the bike would fire up right away. It was not an easy thing to trouble shoot. Only thing that pointed to the problem was trying to start the bike at various engine temperatures. The lower the temperature the more freely the engine turned over when starting. I don't know how else to explain this.

Again, this may not be the OP's problem, but if it is, voltages won't tell you anything.
 

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Discussion Starter · #31 ·
Welcome to the forum.

You don't say how much you are riding the bike between starting it. If you just start it and let it idle a bit, it will never recharge and eventually it will kill the battery.

First thing is to charge the battery, start the bike and check the voltage at the battery while it is running at about 5k rpm. It should be a bit over 14 volts.

Let us know what you find.

As far as your comment that the starter sounds strange, put a test light or voltmeter on the power wire lug at the starter and confirm it is not getting power when you release the button. Relays sometime stick ON with cars but I've not heard of that happening with these bikes.
Have an update:

idle after fully charging battery and key out, battery is at 12.8v
With the key turned to on it’s at 12.2v
Turned on while running at 13.7v and moving up
Turned off after running it it’s at 12.6v

friend Helped me open starter. It turns okay
 

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Discussion Starter · #32 ·
Just check battery voltage when running, with and without starter wires connected.

I mean, if you measure over 14V when running before disconnecting it, then there is no reason to disconnect it, it's the battery!

Ah, that amazing instrument called 'a voltmeter'. I'm surprised how many people try to fix electrical problems without one. I tried to persuade someone to get one a while ago for a car fault, and they insisted on getting a bluetooth OBD dongle so their phone could tell them the battery voltage.

Is it a 'Gen Z' thing? Grandpa's tech is old hat, let's throw away the multimeters?
Have an update:

idle after fully charging battery and key out, battery is at 12.8v
With the key turned to on it’s at 12.2v
Turned on while running at 13.7v and moving up
Turned off after running it it’s at 12.6v

friend Helped me open starter. It turns okay
 

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Discussion Starter · #33 ·
Sorry, I read 'charged the battery', my bad.

Do you know if it is a good one though? I have had duff 'new' batteries before.

What is the voltage across the battery before it starts, and after it starts?
Have an update:

idle after fully charging battery and key out, battery is at 12.8v
With the key turned to on it’s at 12.2v
Turned on while running at 13.7v and moving up
Turned off after running it it’s at 12.6v

friend Helped me open starter. It turns okay
 

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Discussion Starter · #34 ·
Just check battery voltage when running, with and without starter wires connected.

I mean, if you measure over 14V when running before disconnecting it, then there is no reason to disconnect it, it's the battery!

Ah, that amazing instrument called 'a voltmeter'. I'm surprised how many people try to fix electrical problems without one. I tried to persuade someone to get one a while ago for a car fault, and they insisted on getting a bluetooth OBD dongle so their phone could tell them the battery voltage.

Is it a 'Gen Z' thing? Grandpa's tech is old hat, let's throw away the multimeters?
Have an update:

idle after fully charging battery and key out, battery is at 12.8v
With the key turned to on it’s at 12.2v
Turned on while running at 13.7v and moving up
Turned off after running it it’s at 12.6v

friend Helped me open starter. It turns okay
 

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Discussion Starter · #35 ·
Have you any alarm or aftermarket anti-thief system installed? They could dry battery if they been installed incorrectly or has any issues.

In first I would check the charging voltage as John told already. If it will be ok, I would check for charge leak. For this you should insert ampermetter (10a min) between positive terminal of the battery and its wires bracket. And now we could check for the leak current when key is off. It should be about zero value. Lets doing those tests and think about next steps.
Have an update:

idle after fully charging battery and key out, battery is at 12.8v
With the key turned to on it’s at 12.2v
Turned on while running at 13.7v and moving up
Turned off after running it it’s at 12.6v

friend Helped me open starter. It turns okay
 

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485 Posts
What was the voltage of the battery once you got to your friend's house?

The simplest explanation is that it is simply not charging properly and you did not have enough voltage to restart. Need to rule that out first before diving into the starter motor.

Can you find something to display voltage while you're riding? That might show what and when the voltage drops, if it does.
 

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This one with battery fully charged. Notice the sounds it makes after starting

This is after turning off and turning on after getting to my friends house
Listening to that, I would say you have a bad battery.

Put a voltmeter on the battery while you crank it. It should stay above 10.5 volts. My guess is you will see much less.
 
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