I have just put my 2A Commando back together having replaced front and rear Isolastics amongst other things. On Friday I got it back together and it started first kick - but the AO red light didn't go out. This is supposed to go out at 12.4V so a quick check with the multimeter and sure enough, battery sits at 12.24. (It's been on an Optimate charger throughout the rebuild of the bike) I put a bulb across the two alternator wires and the bulb glowed bright in response to an increase in engine speed - so the alternator is charging. Reconnected everything and got the bike going again. Checked battery volts and discovered 11.94V on the multimeter despite engine revs. Worryingly through - the alternator wires are now quite warm to the touch!
Switched everything off again and rechecked the battery which appeared to have recovered to 12.2 V. Stumped as to what to do next I put the multimeter between battery positive (earth) and a good earth on the frame, set to 10A DC and on the 20ma scale, ignition off, and discovered a reading of 4ma. I may be wrong but I thought that this was indicative of a drain on the battery, that is to say something is taking current when it shouldn't be?
Having now reached the limit of my electrical know how, such that it is, I would really appreciate some words of wisdom as to what the cause of this problem might be. Given the recent reassembly I suspect that it will be something I have done (or not) in the rebuild?
Thankyou for your attention.
Dave
Instant thought
Replace with a new battery.
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Possible duff battery
I suspected as much. The bike has been laid up longer than intended and hence battery on the Optimate longer than planned. It would not be the first time that I have had to replace a battery after extended Optimate support - never again!
Thank you for your response.
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Some anomalies here.
Yes the Optimate type of battery charger cannot be trusted, They say the voltage is HIGH and therefore fully charged when the voltage is high, but there is NO POWER in the battery. The first action when you are in this situation is to put the battery on a REAL charger where you can SEE 2A going in for 1/2 a day.
Attempting to measure current in these situations if you are NOT sure of how such current checking works it is best NOT TO.
Alternator hot wires? You do not say what your charge system is original rectifier/Zener or replacement reg/rect. The former should NOT have hot alternator wires unless the rectifier has part failed. The reg/rect system can have warm alternator wires BUT you haven't done the full alternator test as per A O Services.co.uk
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Still no success
I bought a new battery and the bike fired up first kick - and then cut out after a couple of seconds and has not started since. I have been over pretty much everything I can think of in both electrics and fuel and remain baffled. All I get is an occasional popping back when I kick it. Incidentally I also get the (AO) warning light on immediately after an attempted kick start, and then it goes off again.
I suspected the Boyer ignition unit but it appears to pass the test of creating a spark at the plugs when making and breaking a connection between the two stator leads with ignition on?
Only other relevant point I can think of is that my multimeter displays 0.3 - 0.4 ohms between battery (+ve) and every earth on the bike. It's not a lot but I would have expected this to be zero?
I would appreciate any suggestions toward solving this mystery.
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Digital multimeters....
... rarely zero properly. It's best to see what it reads when you connect the probes directly together.
Apart from that, I would jury-rig a system bypassing the main loom to feed the Boyer direct from the (fully charged) battery protected by a simple fuse. That would then tell you whether the Boyer was working. If so, start a process of elimination.
I would also consider whether your warning light is correctly wired.
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And so..
Today I ran a fused live direct from battery to the Boyer ignition box as suggested and the bike still refuses to start, although did produce quite a pop back at the end of one kick. Other than that the only sign of life was when making and breaking the contact with the battery which must have caused a spark which produced a small backfire through the carb. So at this point I am inclined to blame the Boyer box - which was on the bike when I bought it 30 years ago so has not done too badly.
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Have you got a spark??
It is of ltd usage trying to start the bike if you haven't got a spark just when you want it ie correctly timed. You do not need to keep kicking to find the spark, pass a magnet across the back of the two silver coils on the pickup plate. (This is the same function as the two magnets wizzing around inside) It must spark.
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Have I got a spark?
I can answer yes to that question. By moving a magnet across the stator coils as you suggest, with ignition on, we get a spark at the plugs.
Since my last post I became so convinced that it was the (35 year old) Boyer ignition unit at fault that I have invested in a new one, and have it fitted. But it makes very little difference. Now I get a "phut" noise at the end of each attempt to kick start, which may be down to the fact that I've had the new battery on charge since I ordered up the new Boyer box and it was fully charged this morning. It's as though the timing was a long way out? When fitting the new Boyer unit I have static timed the bike to 31 BTDC as per instruction.
Hopefully, at least the black box has now been eliminated, as has the stator coils, the rotor, the stator leads, ignition coils, plug leads and caps as all have been replaced with the ignition unit replacement.
I remain of the opinion that something I have done whilst separating the frame from the engine assembly by enough to fit the front and rear isolastics has caused the problem - but I cannot get to the bottom of what it might be?
Only other "symptom" is that I notice the I get a spark at the positive terminal when I connect the earth lead to the battery with the ignition off?
Any good suggestions gratefully received!
D
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If I understand you...
... the positive side of the battery is connected and you're getting a spark when you connect the earth lead. This obviously means that something is live even when switched off. I would connect a 10 amp ammeter between the earth lead and the battery terminal and see what it is reading - should be zero. If not, than I would start to trace through the loom, removing components till the reading falls to zero. One possible culprit might be the horn which (at least on earlier machines) is permanently live with the button earthing the other side.
One other thought: do you have an earth lead connecting the engine unit back to battery earth? Isolastics can be quite good insulators. I seem to remember a red lead attached to the top iso mounting (cylinder head) on my Commandos.
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hello, not commando. but i…
hello, not commando. but i had a battery terminal break away from inside the battery. the bike would run ok . the battery would show a good voltage. until things warmed up and vibrations kicked in and what with extra load on the battery. the bike just came to a stop. tap the terminals,off you went again.
barry
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The Monster - it lives!
Yes indeed the old Commando burst into life yesterday at the end of another long day. The problem at this eleventh hour was my own fault, Whilst setting the ignition timing (last done 28 years ago), I inadvertantly set it to the wrong mark! Once I had sussed that out she was away and sounding quite crisp. So it would seem that the new Boyer ignition box has cured the basic non starting problem and the thing would have started straight away had I got the timing somewhere in the parish, so thank you all for your patience in bearing with me throughout this epic battle. But before we go high fives all around - remember the hot alternator wires - well, they're back!
After only a few moments running with attenuator light flickering at me throughout, I noted the alternator wires were uncomfortably hot and shut it down. This morning I have removed the stator for examination - see pics (hopefully). The black bits look like something melted and the bubbling on the surface also appears heat related. Only thing I could think to test was the resistance between the two stator wires and that comes in at 0.5 Ohms. It may be nothing at all as 0.5 appears to be within the accuracy of my multimeter (see previous posts).
I also attach a photo of the rotor which looks OK to me but appears to have a piece of surface material missing? Do I need need a new rotor/stator?
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You don't need a new rotor!
The stator might also be ok, you need to test it as per the instructions on aoservices.co.uk info sheets alternator testing as you was instructed before. 0.5 ohms does appear to be a bit low but testing as per web site will sort it.
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We apologise for the delay....
There will be a break in communication as when I I set up this morning to complete the final test of AO Services Alternator Full Output test, the kickstart failed on me! I suspect the (original) pawl to be at fault but it still needs getting into etc, so it will be a little while before I can get back to testing the alternator. Don't you ever lose track of what you originally set off to do? In my case it was discovering part dissolved tank liner in my carb at the end of last year - which has given rise to a whole host of other tasks (including a tank respray) and several hundred pounds spent. What other activity would have provided so many hours of entertainment for such modest outlay....
Meanwhile thank you to all contributors and I hope to get back to the alternator before long.
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Have fun!!!
Indeed have lot's of fun!!!
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In my limited experience,…
In my limited experience, hot bits in the AC circuit occur at places where resistance is higher than it should be, such as corroded or loose rectifier terminals.
It is normal for the AC current to be relatively high (e.g. 10 amps in a 120 watt alternator), but it won't generate much heat until it meets a significant resistance.
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Where were we?
Having now got the gearbox put back together I was out this morning ready to do the outstanding alternator tests. One I had done before which was the headlamp across the two stator wires and the bulb lights quite brightly and shows signs of glowing even more brightly if given a few more revs. Connecting one end of the bulb to the engine with the other still attached to a stator wire produces no light. Tick that box.
Next is the max output test. I picked the black wire from the Boyer Power Box in which to insert my multimeter set to 10A DC. The meter displayed 0.21 at fast tickover, increasing to 0.48 at 3,500rpm. I hesitate to call these Amps because they are so far off expected readings? This was with all lights on, but it didn't really seem to make much of a difference. The red attenuator light was glowing brightly throughout. Have I chosen the correct wire to test? Other option is Red (to earth). The other two are yellow and are inputs from the alternator.
Finally the rotor still appears to be uniformly magnetic and hangs on determinedly to my screwdriver as expected.
What do these numbers suggest?
One final point of curiosity, many years ago I lost one of the spacer tubes that go on the three alternator mounting studs. The original spacers were a half inch long, which struck me as excessive, the rotor being about a quarter inch recessed against the stator front face. I produced three spacers that were shorter but long enough (a) sufficient to clear the primary chain but also (b) short enough to position the rotor almost flush with the stator when installed. Was this correct?
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That looks all good.
In fact your repositioning of the stator spacers seems about right. The alternator test looks good. And the AMPS test seems ok. Can you replace the Boyer reg/rectifier with a standard rectifier? ie the traditional Lucas one. If you look on my web site it says doing this should replace charging (no regulation) but do not go for a long ride without the lights on!
You can return the Boyer Reg/Rect to Boyers for testing or you can send it to me for testing.
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Looking good?
I actually have a spare Boyer Power Box that I replaced in 2010. I sent it back to them and they returned it No Fault Found and even returned my cheque (£15 - those were the days). I had little hope for it and bought a new one in its absence, so this one has been on the shelf since then. I have rigged it up to the bike today and the numbers for the maximum output test are different. At low revs it was 1.2 and it increased to around 2.0 on the same scale of my multimeter at higher revs.
The bike came to me with Boyer Power Box and ignition so I have none of the original stuff that has been replaced.
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The maximum output
The max output test is only part done with the power box, ie reg/rect of any sort. As such a reg/rect is controlling the voltage all the time. But if you do the full output test with a traditional (bridge) rectifier with your lights as the load then you can reasonable be sure you are gettingg all you should get.
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Back to basics
I have no bridge rectifier to hand so cannot easily go further down this road. What I have done is to swap out the Boyer Power Box and replace it with another, which has been checked and confirmed OK by Boyers (albeit 14 years ago, since unused.) This "new" box has made no material difference to the situation . The red light is still glimmering at me and the alternator wires are still getting hot. I think that probably rules out the Power Box as a culprit?
Even though the Maximum Output test was only part done, if the balance of probabilities remains that the stator is a good unit - then I am back to a connection or connections that I have disturbed, or incorrectly replaced during the split of the bike to accommodate the replacement of Front and Rear Isolastics as I have no more mysterious black boxes to blame?
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it almost looks as though…
it almost looks as though the resin has popped at each coil position. possibly overheated.
barry
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The stator
I agree about the appearance of the stator, but if the values measured in the alternator Output tests look good, I'm at a loss? The symptoms are that (a) the attenuator light flickers all the time or is on brightly when lights are on as well, which suggests lack of charge into the battery to make up outgoings? Symptom (b) is that the alternator wires are uncomfortably hot after a couple of minutes running.
During the output test I measured 0.28 rising to 0.43 with my multimeter set at 10A DC. I was expecting to see a value of around 9 Amps according to the Test Schedule - so what was I measuring that was still considered acceptable?
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Output test
I have now had the original Boyer Brandeson for testing-it is dead. very little output and warm alternator wires as expected. If the regulator/rectifier fails they do tend to short out the alternator hence hot wires. We await full output test from Dave, this will clarify if the alternator is also duff.
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Output tests
I have just run through the Output tests with the new Rectifier and running the motor at 3000 produces around 7.75 Amps. 3500 gets it nearer 8 but it doesn't seem like it will do more. I already checked that the stator is not earthing with the headlight check.
So it would seem that the Power box was the culprit all along and the alternator may well also be passed its best? Do I need a new one that shows 9 Amps? I would be interested in the alternative to the Boyer box Alan, as you mentioned earlier. Is it the Unit identified as A-Reg One?
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Further tests
I have recently tested my rotor's magnetic strength against one borrowed from a pal and report that it is much better! It supports its own weight off the blade of a vertical screwdriver, which is more than the borrowed item could do! I feel this rather confirms that my stator may have fallen casualty to the problem with the Boyer Bransden box (and age!) ?
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Please ignore the comment about 4ma - I blame operator error!