problem with Triumph TRW motorcycle ignition, help please
Discussion
I have just sold my 1964 trw, motorcycle, it was very original and ran like a clock, ammeter showed a good charge , the new owner bought it without seeing it and trusted my description, he was pleased with it upon receipt, saying it started and ran well.
however the 2nd day he tried to start it, it would only start on EMG, and ran lumpy, (which I know is normal thing for engines while on EMG),
we have established that the battery is good, and power is coming out as lights etc work,
Can anyone offer any help please, although I sold it as is, I feel really sorry for him, this bike had been one of the most reliable bikes I have ever owned,
I suspect a failed rectifier, but as the bike is so far away I can not do any checks, and looking for info to assist him
many thanks
michael
however the 2nd day he tried to start it, it would only start on EMG, and ran lumpy, (which I know is normal thing for engines while on EMG),
we have established that the battery is good, and power is coming out as lights etc work,
Can anyone offer any help please, although I sold it as is, I feel really sorry for him, this bike had been one of the most reliable bikes I have ever owned,
I suspect a failed rectifier, but as the bike is so far away I can not do any checks, and looking for info to assist him
many thanks
michael
Welcome!
You'd probably find more knowledge on a Triumph or British bike forum... but I'll have a go.
I assume that the TRW still has the 6-volt system that uses the light switch to control alternator output.
I've never run a bike with 6V alternator electrics - in 1971 I converted the first one I had to 12V/zener diode/capacitor before I even rode it - but if I remember correctly, EMG is intended to power the ignition when the battery is dead, and connects one alternator coil directly to the ignition system, leaving the other two coils connected to the rectifier in order to charge the battery.
So...
If the battery is charged, and still powers the lights, horn, etc., that suggests that it's not the battery, nor the fuse (if it has one).
If the battery is fully charged, a rectifier problem wouldn't have any effect until the battery went flat.
The points and coil must be working, or it wouldn't run on emergency.
The only thing I can come up with is a break in the circuit between the normal ignition position of the ignition switch and the points/coil, or, if the ignition switch doesn't have a position for lights, a break between the battery and ignition switch.
I guess he'll have to do some troubleshooting with a multimeter or a test lamp.
You'd probably find more knowledge on a Triumph or British bike forum... but I'll have a go.
I assume that the TRW still has the 6-volt system that uses the light switch to control alternator output.
I've never run a bike with 6V alternator electrics - in 1971 I converted the first one I had to 12V/zener diode/capacitor before I even rode it - but if I remember correctly, EMG is intended to power the ignition when the battery is dead, and connects one alternator coil directly to the ignition system, leaving the other two coils connected to the rectifier in order to charge the battery.
So...
If the battery is charged, and still powers the lights, horn, etc., that suggests that it's not the battery, nor the fuse (if it has one).
If the battery is fully charged, a rectifier problem wouldn't have any effect until the battery went flat.
The points and coil must be working, or it wouldn't run on emergency.
The only thing I can come up with is a break in the circuit between the normal ignition position of the ignition switch and the points/coil, or, if the ignition switch doesn't have a position for lights, a break between the battery and ignition switch.
I guess he'll have to do some troubleshooting with a multimeter or a test lamp.
Hi Gareth
Thanks for taking the time to reply, I do have the question on HMVF but no joy yet,
My bike is the late mk3 TRW so has separate switches for ign and lights,
I think you have hit the nail on the head suggesting a break between battery and ign switch or ign switch to points/coil
He is calling me tonight and I will pass that info on, I thought about getting him to turn ign switch on to run position, then kick bike over slowly, and note if ammeter moves when points move, this will hopefully tell if he has power at points,
He is in Belfast and I am in norfolk, so it’s difficult,
Once again, thanks for your time
All the best
Michael
Thanks for taking the time to reply, I do have the question on HMVF but no joy yet,
My bike is the late mk3 TRW so has separate switches for ign and lights,
I think you have hit the nail on the head suggesting a break between battery and ign switch or ign switch to points/coil
He is calling me tonight and I will pass that info on, I thought about getting him to turn ign switch on to run position, then kick bike over slowly, and note if ammeter moves when points move, this will hopefully tell if he has power at points,
He is in Belfast and I am in norfolk, so it’s difficult,
Once again, thanks for your time
All the best
Michael
Its a long time since I've done anything on one of these, so all this is trusting to memory. Assuming its a coil ignition/alternator bike...
The alternator should have 6 coils and three wires from it. 2 of the coils are connected together and used for ignition. The other four are for lighting. When the ignition key is turned to the normal position, the two coils are used for starting (obviously!). If the battery is flat, and the Emg (Emergency) position is used, then all 6 alternator coils are used for starting. As you probably are aware, when this position is used, as soon as the engine fires, the key should be turned back to the normal position. Never, ever, leave it on Emg!
From the description given, I would expect the problem to be that at least one of the alternator coils has failed. That used to be a common fault even in the 60's. Checking the alternator is easy enough to do, all that is needed (old school way!) is a bulb in a holder, some wire, and crocodile clips.
Hope this is of help!
The alternator should have 6 coils and three wires from it. 2 of the coils are connected together and used for ignition. The other four are for lighting. When the ignition key is turned to the normal position, the two coils are used for starting (obviously!). If the battery is flat, and the Emg (Emergency) position is used, then all 6 alternator coils are used for starting. As you probably are aware, when this position is used, as soon as the engine fires, the key should be turned back to the normal position. Never, ever, leave it on Emg!
From the description given, I would expect the problem to be that at least one of the alternator coils has failed. That used to be a common fault even in the 60's. Checking the alternator is easy enough to do, all that is needed (old school way!) is a bulb in a holder, some wire, and crocodile clips.
Hope this is of help!
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