Starter motor issue?

[p.dath]

My bike was run flawless for the last year, but for some reason I am having no end of electrical problems at the moment.

In the the last two weeks the rectifier/regulator and battery have been replaced.

The problem I have now is when the bike is cold, like the first time I use it in the morning, it has become hard to start. Specfically, I feel the starter motor is not turning over as fast as it should be. Once the bike is warm the bike starts fine, and the starter motor turns over at what I feel is a normal rate. I can come back and start the bike an hour later and it is also fine.

My initial thoughts are that either the starter motor is not getting enough current to turn over properly, the starter motor itself has an issue, or I guess potentially the load on the starter motor is more than it can handle.

So considering the first issue - current getting to the starter motor. I'm thinking this could potentially be the starter relay, a fault in the cable, or more likely a loose connection, or even an issue with the grounding. I could measure the impedance of the cable to check that. Note sure how I can check the starter relay. Ideas?

Second potential issue, the starter motor itself. Any idea how this could be tested? What are common issues that cause a starter motor to turn over slowly? The brushes? Is the starter motor on a Honda CBR 600 a servicable item?

And lastly, the load placed on the starter motor. No idea what to do here.

Remember, this issue only occurrs when the bike is cold, and I have a brand new battery. Ideas?

[p.dath]

Just had another thought. I'm not 100% confident about the stator on my bike. If the stator was a little bit sick, could this create a load on the starter motor (aka, does the stator create a load on the starter motor)? Does the alternator start turning over as soon as the starter motor starts trying to crank the engine?

[Motu]

Alt,battery and starter are one system - a fault in one will often bring the others down too.

[bogan]

mine has been hard to start over winter, due to not knowing best position for the choke, which in turn causes the battery's charge level to go down, my short commute with the headlight on dip isn't long enough to charge it properly (battery is getting old also), if you charge the battery properly with a good charger will it still turn over slowly?. Cold denser air could account for it being slightly slower to turn over also?

[neels]

Could be faulty connection between the battery and the starter motor.

A quick way to check the starter circuit is to chuck a multimeter between the battery negative and the engine casing, and between the battery positive and the starter terminal. Hit the starter and see if you are losing any volts across the cables. It's much more effective to check the volt drop of the cables with current than measure the resistance. Check it cold and then hot and see if there is a significant difference.

Of course given that it's a bit colder at the moment, it's not unusual for the starter to turn a bit more slowly, as the battery doesn't work as well when cold. Once it's warmed up a bit either by turning the bike over or charging it will supply more current.

[Warr]

............chuck a multimeter between the battery negative and the engine casing, and between the battery positive and the starter terminal. Hit the starter and see if you are losing any volts across the cables. It's much more effective to check the volt drop of the cables with current than measure the resistance. Check it cold and then hot and see if there is a significant difference.............
Exactly What he said ...

[davereid]

Could be faulty connection between the battery and the starter motor.

Neels and Motu are on to it.

Your battery must be in good condition, and fully charged before you start. A new battery, is no guarantee that the battery is fully charged - frequently it will be filled with acid, then you are on your way.

Your auto electrician would do a couple of things here that you can't do. He would test your battery by putting a big load on it. He would measure charge current at several rpms, and measure the current going into the starter motor, to ensure it is not drawing too much (shorted winding ?) or too little (brushes - connections / solenoid faulty?)

But you can do some tests with a basic $10 DC voltmeter...

So..
(1) Check your battery is charging. With headlight on, engine running at about 3-4000 rpm, the battery should have about 14 ish volts on it. No need to panic +/- 0.3 volts on your $10 meter.

(2) Turn bike off, remove key, Have a beer. Check battery. 12.6 volts is about right.

If you pass 1 and 2.. seems likely you have a good charging system, at least as good as you can check with your $10 meter.

(3) Now it gets tricky.
Crank bike measuring battery voltage.
Depending on the draw of the starter motor, the charge on the battery, and the battery condition, it may drop as low as 10 volts. Paradoxically, a lower drop may not mean all is well - it may indicate poor earths, high resistance cables, a faulty starter solenoid or other poor connections.
Note the result.

(4) Repeat test, measuring voltage drop across starter motor itself. The difference from battery voltage is the voltage drop across all your leads and the starter solenoid. Less is good !

IF cranking

- Drops battery voltage massively we know we have a starter motor drawing a lot of current (shorted windings, siezed motor, excessivly thick oil) OR a bad battery
- There is little voltage change at the battery but lots at the starter we have poor connections, or dodgy solenoid
- There is little voltage change anywhere we have poor connections, or faulty brushes

Good luck !

[pete376403]

Just had another thought. I'm not 100% confident about the stator on my bike. If the stator was a little bit sick, could this create a load on the starter motor (aka, does the stator create a load on the starter motor)? Does the alternator start turning over as soon as the starter motor starts trying to crank the engine?
The alternator rotor is either right on the end of the crank, or gear driven from the crank, so yes, it is turning as soon as the starter motor starts (given that the starter gear train and sprag clutch are working correctly) However at cranking speed the alternator output (and therefore resistance to turning) is going to be negligible.

There are a few charging system fault finding charts on the net, my favourite is http://thegsresources.com/garage/gs_statorfault.htm

[The Stranger]

You have that electrical troubleshooting information. Use it!

Re-read motu's post.
It's largely pointless checking just one component of the electrical system. Often as not a fault in one part will manafest in another i.e. rooted regulator fucks the battery. You replace the battery, but that's not the actual fault.
So the regulator was replaced, was that because of problems with the stator and/or did it cause other problems? If it has damaged a cell in the battery it *could* be causing what you are seeing.

Using the information that you have in that link you should check it end to end in the sequence it says, or you are just wasting time and money.

[Owl]

Good thread and I'm going to have to try some of these tests myself.

I have pretty much the exact same issue with my S3. I thought my battery was dying, so replaced it, but the issue stayed. Apparently there's nothing wrong with my charging system (14.2v) and it's good for an S3. :scratch:

My concern is the sprag starter clutch, which usually dies from slow cranking and needs replacing.

[p.dath]

(1) Check your battery is charging. With headlight on, engine running at about 3-4000 rpm, the battery should have about 14 ish volts on it. No need to panic +/- 0.3 volts on your $10 meter.

Pass.


(2) Turn bike off, remove key, Have a beer. Check battery. 12.6 volts is about right.

Pass.


(3) Now it gets tricky.
Crank bike measuring battery voltage.
Depending on the draw of the starter motor, the charge on the battery, and the battery condition, it may drop as low as 10 volts. Paradoxically, a lower drop may not mean all is well - it may indicate poor earths, high resistance cables, a faulty starter solenoid or other poor connections.
Note the result.

(4) Repeat test, measuring voltage drop across starter motor itself. The difference from battery voltage is the voltage drop across all your leads and the starter solenoid. Less is good !

Will test. I've been a bit suspcious about this area, mostly because I wasn't sure how to test it.


It's largely pointless checking just one component of the electrical system. Often as not a fault in one part will manafest in another i.e. rooted regulator fucks the battery. You replace the battery, but that's not the actual fault.
So the regulator was replaced, was that because of problems with the stator and/or did it cause other problems? If it has damaged a cell in the battery it *could* be causing what you are seeing.

The battery wasn't getting charged. The voltage across the battery didn't go up when the bike was revved, so it failed that part of the test. So a new regulator went it. It now passes this test. The battery was passing a load test, but I was getting so fucked off with the bike breaking down while I was out I decided to replace it anyway. The battery has never been replaced since I had the bike, and was of an unknown age. The voltage across the stator is not as high as it should be (which is why I don't think it is 100%) - however the voltage across the battery does increase now as you start revving the bike, so it seems to be producing enough power to charge the battery now (just probably doesn't charge as fast as it should be).

[notme]

It seems that you have established that the electricals are fine i.e. your charging system is charging the battery. Now start thinking about the other symptoms, namely that the problem only exists when the engine is cold.

If the bike is really cold when you try to start it, the oil will be thicker and require more effort from the starter motor, also the battery will not be able to provide the same cranking effort when it is cold compared to when it is hot.

Have you recently changed the bike's usual location i.e. from inside to outside storage?

Are you able to try having the bike in a different temperature extreme overnight one night i.e. somewhere much warmer or colder than usual, and see if it gets better (warmer) or worse (colder)?

[p.dath]

If the bike is really cold when you try to start it, the oil will be thicker and require more effort from the starter motor, also the battery will not be able to provide the same cranking effort when it is cold compared to when it is hot.

Have you recently changed the bike's usual location i.e. from inside to outside storage?

Not really. The bike is kept in a garage over night most nights. However I do tend to travel around the city during the day. The last incident happen at about 4pm and the bike had last been running at about 8am that morning. The outside air temperature wasn't too bad.

[notme]

Something you could try as a next step - is the next time you expect the issue to occur like first thing in the morning, try connecting another battery across the bike's as if it had a flat battery and you were jump starting it (assuming you have access to a charged bike or car battery and jumper cables). Make sure you know how to jump start properly or ask here.

If it starts fine with the starter spinning nice and quickly, you know that the starter wants more current when the bike is cold. That would confirm that it's a temperature related effect. If not, you might have to hunt for loose/broken/corroded wires around the starter circuit.

[pete376403]

You say the stator may be dodgy - not charging as fast as it should. You also say you're doing a lot of round town running. So, frequent starting, lights are on all the time, using indicators more than usual, brake light too probably. Perhaps you are taking more out of the battery than the short runs around town put in.
Plus the other checks mentioned all bear looking at, battery earthing to frame, frame link to engine if rubber mounted engine. Star washers between the wire terminal and the metal are good, as is no corrosion or paint. Any signs of overheating/discolouration in connectors that could indicate a bad connection? Electrics are easy if you get the basics right.

[notme]

........... Electrics are easy if you get the basics right.

They are, and they are not the magical mysterious thing that some believe them to be! This belief is why some people will blame an unknown fault on "something in the electrics" when it can often be something else - mechanical or otherwise.

p.dath - you have the troubleshooting chart given by pete in the 8th post on this thread - http://thegsresources.com/garage/gs_statorfault.htm and it sounds like you have run through it, if you have then you don't have a charging system problem, so don't worry about the stator or any other part of the system.
Of course, if you haven't run the troubleshooting chart then that's the first thing you need to do.....

Pete might also be on to something above, in that there could be no problem at all, and it's just the usage pattern of around town running that is causing the "problem". You can prove this one by going for a good ride (say an hour) then leaving the bike overnight and seeing what happens.

In the end, if the electrical chart shows no problem, and the bike does start fine even if it sounds like it is cranking slow sometimes, then do you really have a problem? I'm about to go start my (near new, perfect working order all systems go) car to go to work, and it's below zero in the gargre - if i listen carefully it will crank slower but that's just how things work :-)