Meanwhile I have to post about another issue with my bike, wondering if I have to prepare for some headaches or not..

More than half of the time, while engine is running, voltage is steady, 14v, +/- 0.1 v.
but there're days (not more than 2 in row) when charging system is on different mood.

and what happens on that days - after cold start initially voltage is 14 and couple minutes later it starts play, with sharp jumps below 14.
these jump steps are quite random, but play range is very determined - any voltage in 10.5-14 range.
thing is that this happens in spite of any load (lights etc.) or rev count.
steps are sharp and unpredictable. as well as there might be successive jumps also randomly, e.g. 14.0 - 12.8 - 11.5 than 14.0 again and so on.

on such days around 60% of time I've got wrong (<14) voltage and when I turn off the engine voltage gets back to ~12.5.

I think that battery is healthy, also, most of the parking time it is connected to maintainer.
Same for the voltmeter, as this droppings are portrayed on brightness of lights as well.
Wrong or correct voltage, engine performance is all same.

I haven't inspected all cables so far, but not yet sure that such determined range could be caused by leakage.
what else - magneto and reg/rec.
does these symptoms look familiar to your experience?
I've already ordered spare regulator but still very concerned about extent of possible damage caused by wrong voltage - battery? ignition units?

If it never gets over 14V you have no danger of burning anything, all components can stand 14V, so no issues

biggest issue is when regulator lets voltage go OVER 14V is cooking the battery

if bike is running ok and you see 12.5V when switching off, then i dont think you have a problem

Thanks, felt some more calm after reading : )

just don't like having something different from normal value with unknown reason.

Try the other regulator and check values.

While it may not be causing you to stop just now, the 'problem' will get worse and that will result in a flat battery.

It is probably a bad connection from the engine stator through to the battery .. check each connector along that line.

Good luck.

I had some problems with the reg/rec when earth that connects to it was not 100%, it looked nice & tight, but the problems went away when I replaced it.

Thanks to all
Yes, maybe there will be no more "strange day", maybe other reg.rec. will work fine but guess I will still have to prepare for the long check-ups on quite a short distance of cables )
Indeed, certain amount of luck is needed )

I remember, there was small piece of cable bolted on reg. body, which obviously must be an earth connection. ok, that thing must become one of the first subject of inspection.

Everything you mentioned is how it should be!

With the engine running you need voltages between 13-ish volts to maximum of 14.4~14.7

and Yes, after a few minutes with the engine off, you will only get about 12.5~13volts out of the battery!
Anything lower than 12.5v and your battery is starting to go bad or you have something draining the battery!

I went through two rec/regs before discovering that a build up of paint and rust beneath the device was reducing the integrity of the earth. I've now run a second earth from the bike frame to the body of the regulator and it seems to be holding steady.

No. Reread the first post!

But with the engine on the voltage is dropping sharply down. Then back up, engine still on.

Indicates to me either

the charging system is stopping for some small time

OR

there is a short some where in the wiring.

Lower voltage at higher rpms than idle is usually a bad reg/rec.

Well, while still waiting for new rec/reg to arrive, I think I've found a reason.
wiring and connections are good.
I have to blame that guy:


well, it (is) was my starter solenoid
something like that: https://www.ebay.com/itm/New-Ford-St...item2f076b0a1a
When 2 standard solenoids (one oem and one non) have failed during one month, I decided to update to something stronger ))

so, after 2 years of service this unit started somehow stealing some power. after removal I also discovered that some unnecessary shaky things are going on inside. I'll take some time to disassemble this unit to try to find out if there was any water inside, otherwise this malfunction must be caused by vibrations, I think.
suprisingly, starer was still spinning quite well.

Luckily, I had a spare one, noticeably better quality, so already switched them.
like previous one, I attach this thing on the frame, but this time used twice more rubber between frame and solenoid, as well as gasket maker around connections as an insulation. previously I've used only heat-shrink tubes. hope that that this time it will work >2 years.

By the way, this big solenoid requires extra relay to be activated. I use car's standard 40A relay. for emergency I also have one secret 60A button, which never had to use so far - direct connection to starter

no evident traces of water inside.



Guess I've found a reason but I haven't found a reason for this reason

Will have a spare one for the future as well.