(26-07-14, 02:05 PM)keratos link Wrote: [quote author=Fazerider link=topic=14120.msg159821#msg159821 date=1406379665]
How did you determine that the starter relay was fine? If it was by using the continuity range on a multimeter that could give a misleading result. The meter only passes about ten milliamps to measure the contact, the starter is trying to take several thousand times as much current, a few tenths of an ohm can be enough to stop it yet a meter will see good continuity.
Try measuring the voltage between the output of the starter relay and the battery negative.
If you get 12v (nominal) and the motor doesn't spin then you've an (intermittent) connection between the relay and starter or between starter and earth. If you get a lower voltage and the starter doesn't spin, it's probably contamination of the relay contacts.
I did both. Continuity and volts. All OK. The meter is a ut71 , £150.
You forgot to mention the starter cut off relay. I tested this too but it's a complicated box so often the best way is to swap it out and see. I may do this. It's definitive not the starter relay or the motor or the main switch or the run switch or the neutral switch. I can't think what else it might be
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If the starter relay goes click when you press the button the cutout relay is fine, that's why I didn't mention it.
So what voltage did you get on the output of the starter relay? (Measured with the starter etc. in circuit.)
I repeat change the starter relay.
To answer questions...I have retested the starter relay
When I press start I get continuity across the high amp terminals. I get a voltage of 11.89v and sometimes less. On each occasion the motor turned. When it failed to turn the voltage was the same. The battery voltage is 12.8v.
I just don't see how it can be the starter relay when all readings are identical when the motor turns, and when it does not??
Also... On the odd occasion it didn't turn the starter, I held start down and like magic after a delay of 10 second, it started. Like weird
What you most likely have is copper corrosion or burning of the 30 amp contacts within the the Starter relay itself creating high resistance in the circuit. It gives exactly the symptoms you describe.
Measuring the voltage across it is not an effective test, you would need to check the current flow and since that can be 30 amps no ordinary meter could be used to test it.
You could try testing the resistance across the contacts by disconnecting the two large cables to the battery and starter motor.
Connect the test leads to those connection on the relay, set meter to Ohms, if reading is above zero when starter button is pressed, change the relay.
You can buy a brand new starter relay for £20.
You are correct, if the voltage between the starter relay output and the negative terminal of the battery is 11.89v and the starter motor doesn't turn, that tells you that the relay is not the problem.
So you have poor continuity between the relay and starter.
There are other possibilities: poor grounding of the engine or the starter itself needing a clean and new brushes, but if the thing spins reliably when you put a jump lead to it that makes these less likely.
Unfazed: sorry to disagree with you, but the voltage measurement is very useful. You can't have a 12v output from the relay with the motor not turning and blame the relay!
Read what I wrote again. I said that Voltage reading are not an effective test, useful yes, but not always an effective test.
If the starter relay is high resistance then the voltage drop will occur across it giving a low voltage at the output.
In what way is that not an effective test?
(26-07-14, 06:37 PM)Fazerider link Wrote: Unfazed: sorry to disagree with you, but the voltage measurement is very useful. You can't have a 12v output from the relay with the motor not turning and blame the relay! Precisely.
It can surely only be an issue from the 12+ starter relay output , along the lead, to the starter terminal.
Can't be the motor as this spins freely when hotwired .
What I did also was short the relay output with the 12 v battery terminal. Very close together and I used car battery jump lead croc clip to short the two. The motor turns every time so it can't be the lead to the motor either. And it's not the motor either or the grinding to/of it.
God this is annoying
Intermittent faults are a nightmare. All you can do to pinpoint it is to ignore the results you get when it's working OK and concentrate on those you get when in faulty mode.
Perhaps the next step is to try a voltage reading on the starter motor itself to eliminate the cable and connectors from the relay as being the cause.
(26-07-14, 08:14 PM)Fazerider link Wrote: Intermittent faults are a nightmare. All you can do to pinpoint it is to ignore the results you get when it's working OK and concentrate on those you get when in faulty mode.
Perhaps the next step is to try a voltage reading on the starter motor itself to eliminate the cable and connectors from the relay as being the cause. Yep. But as above... I shorted the battery and relay output (to motor) and all is fine so it's not the cable from relay to motor
My point was that that may be a false positive… i.e the fault, wherever it is, wasn't exhibiting itself on those occasions. The 12v output from the relay when the motor didn't spin, on the other hand, is conclusive evidence that the fault lies downstream of the relay.
There are only a few connectors to look at, I'd be inclined to scrape and tighten all of them and if that doesn't chase the gremlins away, whip the motor out and check all's well inside. If I had to put money on it, I'd guess glazing of the armature/worn brushes is the likely culprit.
thanks for the help and persistence;
what I would say is that it is defo not the motor; the motor spins every time I short out the relay output to battery+. Every time; I've lost count, maybe over 100 times.
I have looked at the wiring diagram on 8-11 in the Yam shop manual. Ive tested, as much as I can, the terminals and looms. With ignition on, run switch on, I "hear" the cut off relay energise and I confirm voltage and continuity.
When I press the start button I hear the clunk of the starter relay , and confirm voltage and continuity. So no issues with any of the switches and cut-off relay otherwise the starter relay wouldnt energise when I press start.
When I get no engine start, I hold the start button (no spin) then whilst holding I short the relay+ and battery+ with a pair of big pliers, motor spins - this works every time the start switch fails to spin the motor; It cant be the motor or the cable to it from the starter relay. I cant be anything "upstream" from the starter relay or the relay would fail to energise when I press start (according the the wiring diagram)
All I can think of is some intermittent mechanical failure inside the starter relay moving parts. I just dont get it. Its ridiculously illogical. I think I'll have to replace the starter relay anyway . So I have ordered a second hand one from eBay for £5 with 28day warranty. If it works, and removes the problem for 28days, I will buy a new one.
Would it not be best test these things when its cold, ie before you've tried starting it on the button at all?
There's more chance then, that the results you get are 'true'.
If you've tried once or twice on the button before testing, the chances are that the third time, the testing time, has sorted the issue again and the readings are false?
Has been mentioned before but nobody actively mentioned trying it from cold before trying it on the button if that makes any sense...
(27-07-14, 02:38 PM)davidkent link Wrote: Would it not be best test these things when its cold, ie before you've tried starting it on the button at all?
There's more chance then, that the results you get are 'true'.
If you've tried once or twice on the button before testing, the chances are that the third time, the testing time, has sorted the issue again and the readings are false?
Has been mentioned before but nobody actively mentioned trying it from cold before trying it on the button if that makes any sense...
It can happen cold, warm and hot. First thing in morning, during a rideout, after getting in, and after leaving it an hour, two,three hours. There is no pattern or logic.
I've ordered a new solenoid so will wait and see what that does.
hats off to unfazed...
cos I swapped out the starter relay and all is fine now.
but when I tested the relay all was fine - just goes to show ... manuals, guides, and manufacturer info is no substitute for good ole experience
cheers guys and apologies to unfazed who will have felt ignored , but who is now fully vindicated and was right all along
Apology accepted Keratos.
Glad to see another fazer back on the road and not giving its owner grief :lol
It is most likely copper corrosion or burning of the the internal high current contacts.
I have seen it before when working for the telecoms company on high current copper bus bars contactors and my neighbours car a few years ago whose arrogant smart ass mechanic did not believe it either 
Dismantle the starter relay out of curiosity to see what is actually wrong with, which is what I did with the car solonoid to prove a point to my neighbours mechanic. :lol
yes , point taken - twice , cheers for the humiliation :o :b
Relay disassembled, partly, as the fault is identified. Note the underneath of the fuse holder, top left in the image shown inverted, the metal track that carries the high amp current from battery+ to starter motor, has corroded away. Hence problem and hence increasingly intermittent ; used to start if I gave the side of bike a firm gentle nudge! Got to the point where it wasnt starting. What I didnt check is continuity across the two high amp terminals. I need not have started to disassemble the bottom of the relay, so I guess I was just showing where I was up to !
Jeez guys, we should just listen to unfazed
[smg id=2064 type=preview align=center caption="IMG 20140801 204154"]
(01-08-14, 08:28 PM)keratos link Wrote:yes , point taken - twice , cheers for the humiliation :o :b
Actually keratos was not getting at you or trying to humiliate you and I was sincere in accepting the apology. :thumbup Fair play to you for coming back on and saying what you said. :thumbup
Corrosion can do funny things with meter tests, the only way to test it properly is using a high current meter.
The smart ass arrogant mechanic said to my neighbour when he explained what I had told him said and I quote "What the foc would a fellow who fixes phones know about car electrics" :eek
He was insisting that the starter motor was faulty and it would cost 100 pounds, I got a solonoid from the breakers for a tenner and put it in for him.
I opened the solonoid showed him what the problem was and he took it back to mechanic who told him to foc off, he did and changed to a different mechanic which he has been using since :lol
(01-08-14, 10:18 PM)unfazed link Wrote:[quote author=keratos link=topic=14120.msg160678#msg160678 date=1406921303]
yes , point taken - twice , cheers for the humiliation :o :b
Actually keratos was not getting at you or trying to humiliate you and I was sincere in accepting the apology. :thumbup Fair play to you for coming back on and saying what you said. :thumbup ...
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no no no, I was only kidding, just messing around. I dont feel humiliated dear foccer, just kidding. Guess my humour needs to grow on people. naughty me :evil
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