Voltage Drop on Starting

[Grahamm]

Here's the next chapter in the on-going saga of my Fazer not starting properly.

As mentioned in other threads, I'd seen the Temperature Gauge jumping up to the top of the scale, which lead me on a false trail of thinking the coolant sensor was buggered, but it turned out to be fine.

What I didn't realise was that the ABS warning light was flashing too and, according to an FZ6 Service Manual I found online, it flashes every 0.5 seconds if the voltage drops below 10v.

I phoned Yamaha UK's Tech department and spoke to one of their guys and he suggested that the voltage drop was caused either by the starter solenoid or the starter motor.

I've tried cleaning the contacts on the starter solenoid and its resistance seems to be within tolerance, so could a duff Starter Motor cause that much of a power drain?

I could take it out and disassemble it, but that looks like a lot of work, so I'm thinking of splashing out £30 for a replacement from a breaker's on eBay.

So the question is, I've looked at the Haynes manual , but how easy is it really to take out an old starter motor and put in a new one? Anyone got any tips?

PS I'd also tried checking the plugs (well, the nearest one on the right hand side of the bike) and although they're a bit old, it didn't look faulty according to the images in the Haynes book. It did say about checking the resistance of the Spark Plug Cap, but although I could get it off the plug, it said "unscrew the cap from the HT lead", however it seemed to be directly moulded onto the lead somehow.

The bit that might have been the part they suggested I unscrew  had a mould line that seemed to run all the way down the cap and I didn't want to start buggering about with that in case I broke it! So can that be unscrewed or not?

[Fazerider]

Changing the starter sounds like waste of time and money to me. If the solenoid is disengaging OK, the motor won't be able to draw any current.
I'd guess the problem is more down to voltage drop caused by the headlight (if I'm right in thinking that's lit all the time when the ignition's on).
Or a duff battery.
What's the actual voltage measurement across the terminals?

[Grahamm]

I'd guess the problem is more down to voltage drop caused by the headlight (if I'm right in thinking that's lit all the time when the ignition's on).
Or a duff battery.

The headlight only comes on when the engine actually starts running. The battery is only a month old and has been drop-tested ok.

What's the actual voltage measurement across the terminals?

If the battery is freshly charged on the Optimate it can get up to around 13.35v. I'd been trying a few things earlier today and then put it back on charge, so it was around 12.96v when I tried it just now which dropped to about 12.6 when I switched on. When I tried cranking it, it did start, but the volts dropped down to 8.51!

So something, somewhere is draining a lot of power and I presume it's either the starter motor or the ignition system.

[Fazerider]

I'll try to take some measurements on mine tomorrow to compare. I'd expect the battery volts to take a bit of a hit while the starter is cranking the engine over, but as soon as the engine's running under its own power the voltage should be back up.
The starter motor ought not to be drawing anything once your finger's off the button. I suppose it could be killing the battery if there's a shorted winding or two in the motor, but I'd be surprised if that is the case because it manages to turn the engine.

[Grahamm]

I'd expect the battery volts to take a bit of a hit while the starter is cranking the engine over, but as soon as the engine's running under its own power the voltage should be back up.

Yes, they take a hit, but they shouldn't drop as low as 8.5v

Once it starts, everything is fine, but what's happened more and more in recent weeks is that if I've been out and parked it, then come back, as it hasn't been on the charger it hasn't enough power to start as cranking it seems to be draining too much power.

The starter motor ought not to be drawing anything once your finger's off the button.

No, it doesn't, but it (or something) is drawing too much to get it to fire when I am pressing the starter.

[Fazerider]

I took the bike out for a run this morning to warm it up for another oil change and made a few measurements for comparison.
It had been standing two days and the battery read 12.7v.
Ignition on, and the voltage dropped to 12.3, though I later realised that the heated grips were drawing current at this point.
Cranking: the voltage initially got as low as 9.5v though rose to 10.1v once it was turning a bit quicker.
As soon as the engine fired and I let go of the starter button the volts came up to 14.0v.
I turned the lights on and it read 13.8v.
The latter two readings were with a fairly brisk on-choke idle of 1500rpm.


If you've a voltage of 10v once the engine is running it still points to a duff charging circuit so far as I can see. Possibly a duff battery (despite its newness). I really doubt that the starter motor is the cause of the problem, but vehicle electrics are good at making me look an idiot.

[bigralphie]

I still think its your stator running hot 

[Grahamm]

If you've a voltage of 10v once the engine is running it still points to a duff charging circuit

It's fine when it's running, but it's the initial drop when I press the starter that seems to be causing the problem.

If I've got the following right, you should be able to see a video clip of what happens here:

https://drive.google.com/file/d/0BzSHRSaNc4Szb2FheEdjYkpaV0k/view?usp=sharing

The voltage is fine to start after it's been charging on the Optimate, but when I hit the starter the side-lights dim, the volts drop to 8.51, however (in this case) there's enough to get it to start.

The problem is when I've been out and it's been sat around for a while not charging, at which point it may be sluggish to turn over or just fail to start as you can see here:

https://drive.google.com/file/d/0BzSHRSaNc4SzMjFodENwdTVSdjg/view?usp=sharing

[Grahamm]

I still think its your stator running hot 

I don't understand what you mean, could you explain, please?

I've checked the stator by unplugging it from the Rectifier/ Regulator and it seems to be giving out plenty of volts when the engine is running. AFAIK it doesn't do anything much when I'm starting it.

[Fazerider]

From that it looks as though your charging circuit is ok, in fact your readings are pretty similar to mine. Even the second clip doesn't make me think there's much of a battery/starter issue, it's churning the engine over fairly well… I'd be more suspicious of the sparks.

[Grahamm]

I'd be more suspicious of the sparks.

The thing is, at times it can be very sluggish to turn over and really struggles.

Regarding the sparks, as mentioned earlier,  I've tried checking the plugs (well, the nearest one on the right hand side of the bike) and although they're fairly old, it didn't look faulty.

I did think about trying to check the resistance of the Spark Plug Cap, but although I could get it off the plug, the Haynes manual said "unscrew the cap from the HT lead", however it seemed to be directly moulded onto the lead somehow and I didn't want to damage it by using brute force.

Does anyone know if I can just uncrew the plug cap or is it actually directly moulded to the HT lead?

[Andy FZS]

Mine unscrew and I'm fairly sure they all do.
Andy

[JoeRock]

If they're old, change the spark plugs for a new set. one less thing to worry about, and its a lot more likely its them than your coils!


On a secondary note, you can't test a battery for its voltage immediately after charging - they hold a surface charge which goes after a few hours, meaning if you check it originally it'll look much higher than it is

[bigralphie]

If I understand your issue , you are not getting enough current to both start and charge
If your coil/stator is breaking down it will not supply enough charge but it will be worse the hotter it gets
You might get a reasonable resistance reading but the insulation may be slowly melting
Only way to know for sure is inspect it for charring

[Grahamm]

Well I was supposed to be going to Nooj's in Newbury to get the annual Shiny Bike treatment, unfortunately, instead I've spent the afternoon having all sorts of fun with the bike because it wouldn't even start now, despite having been on charge all night

Usually that's was enough to get it going, but after the first failure, I checked the voltage and it was 12.5 after one attempt at starting which then dropped down to about 7.9 on the second try!!

As mentioned, the battery has been on-load drop-tested by Vernon's in Portsmouth who confirmed it was ok.

Mine unscrew and I'm fairly sure they all do.

I didn't look at the plug caps again today, but I'll maybe try them tomorrow.

Has anyone else tried removing the HT Leads from the plug caps on an FZ6 Fazer (5VX fuel injected) and can confirm if the caps can be unscrewed or whether they're a sealed unit?

If they're old, change the spark plugs for a new set. one less thing to worry about, and its a lot more likely its them than your coils!

I may well try doing that, but it involves draining the coolant and removing the radiator which I really don't want to try at the moment.

Thing is, though, although duff plugs would make starting it difficult, they wouldn't cause the voltage drop, would they?

On a secondary note, you can't test a battery for its voltage immediately after charging - they hold a surface charge which goes after a few hours, meaning if you check it originally it'll look much higher than it is

Yes, I know that (as mentioned in another thread) but even after leaving it for a while, there's still a good charge.

If I understand your issue , you are not getting enough current to both start and charge

It's ok *once* it's started, whether I can get it going with the starter or by bumping it and it charges fine now I've replaced the Regulator/ Rectifier. The issue is the sluggish turn-over and it not firing I often get when I press the starter.

As mentioned, I got good voltages out of the stator when it was running. Any more in depth checks on that is something I'm really going to have to leave to a garage!

[Fazerider]

...  I checked the voltage and it was 12.5 after one attempt at starting which then dropped down to about 7.9 on the second try!!
As mentioned, the battery has been on-load drop-tested by Vernon's in Portsmouth who confirmed it was ok.

The battery ought to survive at least 30 seconds of cranking the engine over before it sinks that low. Either it's not getting charged or is duff or, as you suggest, the starter is drawing more current than it should. Seems like an odd fault, but hopefully it's as easy a task to swap as it is on the original Fazer. Though... if you need to take the rad off the FZ6 to change the plugs, replacing the starter is probably an engine-out job.

[Grahamm]

The battery ought to survive at least 30 seconds of cranking the engine over before it sinks that low. Either it's not getting charged or is duff or, as you suggest, the starter is drawing more current than it should. Seems like an odd fault, but hopefully it's as easy a task to swap as it is on the original Fazer.

I'm going to take the battery down to a local motor spares shop tomorrow and get them to test it again to see if it's gone duff.

My other hope is to find someone in the Portsmouth area who has a spare battery and a set of jump leads which I can use to bridge over mine and see if the voltage drop still happens.

Though... if you need to take the rad off the FZ6 to change the plugs, replacing the starter is probably an engine-out job.

The problem is that there's virtually no space to manoeuvre between the plugs on the left hand side and the back of the radiator. I have found some instructions which suggest that it is possible with some (well, quite a lot of) fiddling, but I've not tried that yet.

The starter actually looks easier to do, provided you have a very long and thin extension to go onto a socket driver to get to the bolts which are buried in the middle of the engine.

[Grahamm]

Well what do you know, despite what I'd been told previously, when I got the battery tested with a Drop Meter today, it turned out to be duff, even though it was only a couple of months old!

So I've got another one and hopefully that will sort everything out.

In a way it's actually turned out to be beneficial because it's made me get around to learning more about the inner workings of the bike and having more confidence to start doing my own maintenance. Just a shame it was such a PITA!

Oh well, thanks to everyone for their help anyway