Strange voltage indication

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Tornado

Tornado

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Yesterday went out on another shake down run. Had quite a few kickbacks and spits trying to start, never had that many before. Thinking timing might be over advanced and will be rechecking.
Anyway after warm up seemed ok to ride. After a 30 min run around town and a little highway work, noticed the SparkBright volt monitor led indicating low charge volts (amber) instead of normal green at 2k rpm or more. Blipping up to 3500 didn't change it to green, maybe a moment of green at 4k. Turned for home and kept seeing low or discharge warnings until in garage. Note id turned main headlamp off a while back, made no difference. After idling 2 or 3 min while I ran for my multimeter, I checked batt terminal volts. 12.4-12.7 at 1100, and jumping to 13.5+ above 2500 and green came back normal.

Can't understand this. Maybe an intermittant short? Overheating of the reg/rec (typanium...was not feeling hot to touch at thistime)?
 
Question. Which alternator, single or 3-phase?
Guess. Not short but open. A connector somewhere in circuits between alternator and battery. Could also be a faulty ground. Had similar problem with a faulty chinese ignition key switch two weeks ago. Your sensible motorcycle decided to make connection again when back in lockdown.
 
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OEM Lucas single phase and rotor. Wassel EI. Batt is new last season. I've swapped in a new headlamp shell recently and maybe some of those connections have become fussy. Will be going over the wiring and ground points soon.

The SparkBright is wired to connections within the headlamp shell, for convenience. I'm thinking if that is getting a poor ground/live feed at some point, the LED will behave strangely....but the battery and rest of bike will still be getting good charge. Might try a temp direct connect from batt to SparkBright.
 
The 12.4-12.7 figure after a run usually means that it had not charged properly on the run. On the other hand, your starting issues could be caused by low battery voltage. I've read that Boyer ignitions don't retard ignition when battery voltage is low. Noticed a kickback tendency on a bike with Boyer when started in emergency mode (no battery with the Lucas 2MC capacitor). So charge your battery, wait an hour then check battery voltage. Should be about 13V (at least 12.8V). Then start the engine. Agree, do make temp leads from SparkBright to battery.
 
Make sure you’ve got a decent earth to your new headlight bucket and that your earth isn’t being provided by the clutch cable or tacho drive.

...only then start digging deeper!!!
 
Had it on trickle batt tender overnight. Volts at batt terminals 12.8-12.9. Ign on (main lamp off), gets 12.3 at terms. Inside shell, I'm getting 12.25 from the shell edge to a powered on bullet connector. The copper/brass grounding terminal isn't held firmly to the shell via the small rivet...able to swivel it easily. Should still be making good connection via the rivet. I tried crimping the rivet a bit and it helped to give a wee bit more clamping. Not ideal. Noted that even with dip beam on (LED) volts only dropped a little, 12.15-12.2. My Wassell EI booklet states working voltage 10-16v. Also found the static timing to be over advanced, high side of 32-33 deg....and I know my primary cover scale is indicating higher then reality by 1.5 degrees. Knocked the stator plate CCW until got the EI stator/rotor marks aligned, while engine at 30 deg on the alt stator/primary scale. That should give 28.5 BTDC for static timing. The booklet shows for a Commando, "28/31" for static timing.....I assume that means 28 to 31 degrees. Strange b/c all the other listed motors have a single value.
 
One of the most failure prone connections is the block of white wires in the bullet cluster under the tank. The feed comes from the ignition switch to the blinker relay then to the harness connectors. Your ignition and all the headlamp and switch cluster power lines come from that. Take the tank off and check that you don't have a corroded or cracked female bullet socket there. I've witnessed this first hand.

This of course assumes you don't have a MK3.

BTW, I prefer to monitor volts from inside the headlamp shell, at the load side of the wiring. That will tell you if there's a bad connection somewhere, as you may be experiencing.
 
Tornado said:
Inside shell, I'm getting 12.25 from the shell edge to a powered on bullet connector. The copper/brass grounding terminal isn't held firmly to the shell via the small rivet...able to swivel it easily. Should still be making good connection via the rivet.
Click to expand...

The shell terminal is NOT an electrical system 'ground'. The shell terminal is there so the front direction indicators have a connection to harness red which is the electrical system 'ground', not the shell (or the 'frame') therefore the check should be made between the powered connection and harness red.
 
maylar said:
One of the most failure prone connections is the block of white wires in the bullet cluster under the tank. The feed comes from the ignition switch to the blinker relay then to the harness connectors. Your ignition and all the headlamp and switch cluster power lines come from that. Take the tank off and check that you don't have a corroded or cracked female bullet socket there. I've witnessed this first hand.

This of course assumes you don't have a MK3.

BTW, I prefer to monitor volts from inside the headlamp shell, at the load side of the wiring. That will tell you if there's a bad connection somewhere, as you may be experiencing.
Click to expand...
I've replaced the multiblock and the other associated doubles/singles under tank last season with new. Hopefully not seeing an issue there but will keep in mind.
 
Tornado said:
I've replaced the multiblock and the other associated doubles/singles under tank last season with new. Hopefully not seeing an issue there but will keep in mind.
Click to expand...

Tug on the wires. It may be that one of the bullets isn't fully seated.
 
maylar said:
Tug on the wires. It may be that one of the bullets isn't fully seated.
Click to expand...
I believe the warning LED has some heuristics built in whereby it delays any rapid voltage changes, averages them out, so that lamp is not flickering from one signal to another rapidly. This might give the effect I saw if a connection was flaky.
 
Both of my bikes with the Sparkbright voltage monitor alternate steady green and steady amber when the battery is fully charged.
I believe this is just the cycle of the shunt regulator doing its thing.
Shunt reaches threshold voltage (above 13.2v= green showing) and goes to ground.
Voltage in system drops a little ( below 13.2 = steady amber) . After a minute or two of ignition and headlight draw, the voltage drops enough for the shunt to open up. Battery starts to receive charge and VM goes back to green.

Glen
 
In my case reported here, the green was not coming back on, maybe just for a second or two at 3-4k. Then further dropping to red series blinking. Had me concerned engine might die so made for home.
 
Hmmm
That does sound like a short somewhere or poor connection on the charge side of things.

Glen
 
worntorn said:
Hmmm
That does sound like a short somewhere or poor connection on the charge side of things.

Glen
Click to expand...
Just back from another shakedown run. Kick-back/spitting issue seems resolved after some ign timing tweaks. Did not see the LED warning issue....each time it went into red flashes I could get it back to solid amber or green with some higher revs. Might have settled it when poking about in the lamp shell the other day.

Now the biggest issue is the engine is not running smoothly. Like it has a miss or power loss from one cylinder (left)....riding along steady speeds it feels a bit jerky, at basically at all throttle positions, so this would suggest not the idle circuit, correct? Seems worse on cold engine until 5-10 min into the ride.
 
Mine was surging last year. Dropped the carb bowls and one of the mainjets was dangling by a couple of threads.
Tightened that up and smooth running returned.
You can check that the mainjets are tight without dropping the float bowls if the float bowls have drains.
A deep socket will fit in there and catch the mainjet hex.
It's a longshot but worth a look.

Glen
 
worntorn said:
Mine was surging last year. Dropped the carb bowls and one of the mainjets was dangling by a couple of threads.
Tightened that up and smooth running returned.
You can check that the mainjets are tight without dropping the float bowls if the float bowls have drains.
A deep socket will fit in there and catch the mainjet hex.
It's a longshot but worth a look.

Glen
Click to expand...
Will try. Had the mainjet unwind last year as well...it was giving increasingly harsh misfires at 3500-4000+ rpms. Not what it is doing now though.
 
Found an older thread describing similar symptoms as what I'm getting on the misfires....seems head gasket and/or intake air leaks were the offenders. Will be checking those first.
 
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