Defective battery or charging problem or other?

[cliff7]

Poking my nose in, after similar problems found this helpful:-
http://manuals.sohc4.net/general/motorcycle_electrics/HondaMES3.pdf
Forget first page.

[billdn]

Cliff any help appreciated, will read link but can't say I'll understand it
Bryan - I've repeated earlier test you asked and values shown as follows(previous in brackets)
Battery volts engine running 12.47v (12.2v) with negative probe on battery and pos on white wire to block 3.3v, no previous ; pos on black in headlight 12.12v ( 0.73v) ; pos on black ignition 12.16v ( 0.73v); pos on ignition red 0.05v ( 0.49v) so cleaning up ignition switch may have done something?
Cheers
Bill

[Bryanj]

You should still have a higher voltagd on the white wire, more or less full battery voltage after startup.

There are two sets of contacts inside the reg box, or rather one moving one that connects up or down depending on battery voltage. It could be that one of those pairs have high resistance and need cleaning, same as engine contact points realy they can oxidise when not in use

[mike the bike]

As I said;  short black and white together.  This bypasses the questionable voltage reg and supplies the full 12V across the exciter coil.  All being well, it should now charge, so replace the voltage reg.
If it doesn't charge, then the fault is elsewhere.

[billdn]

Bryan - removed regulator, gave points within clean with fine wet/ dry ( dry obviously) and a good spray with electrical cleaner and put back on , no change or possibly lower value on white than before, tried Mike's suggestion and charging ok , so possbly u/s regulator.
A combined rectifier/ regulator is cheaper than new regulator from DS any thoughts?
Or try and source second hand unit from Steve and 400/4 bits.
Cheers Bill
P.S. horn now works - loose wire oops!

[mike the bike]

What the reg does is, when it detects the battery voltage is low, gives a 12V output to the white wire.
Yours isn't doing that.  The test you carried out proved that the reg is faulty.  I would get a combined reg/rec from DSS.

[billdn]

Mike thanks for that👍 wemoto do similar and are local to me so could pick one up to save waiting, are you aware of any problems with this unit, I guess it'll need some support bracket as won't fit directly in place? 

[Bryanj]

Or post me the reg and i will fix it, the standard regs are very reliable and the only difference between 400 and all the other sohc is the way the contacts point

[billdn]

Nice one Bryan can you PM me your address? 👍

[mike the bike]

Make sure it's a 3 phase one.  You mentioned Lexmoto,  they only do small bikes front they?  The Lexmoto 125 that I'm fettling is only single phase.

[billdn]

Mike- no Wemoto not Lexmoto, they're a parts supplier and do good quality parts at reasonable prices. I've used them before , worth a look if you've not seen them on t'net - do mail order too!

[mike the bike]

Doh, brain fart 🧠💨.  I've used Wemoto many times.  Go for it.

[billdn]

Okay! So going for Elextrex RR24 rectifier / regulator - have removed old regulator (off to BryanJ to have a look and thanks for that, may come in handy for other 400 I have) , looks quite straight forward but I'm bit concerned by this part referred to in parts manual as rectifier assembly (ringed in red) should i remove this and 2 red/green wires feeding it also.
Also any tips on mounting it, noted other threads for 550/4 etc but none for 400/4 - guess doesn't need earthing but needs to be kept cool to dissipate heat I guess?

[mike the bike]

The new reg/rec. replaces both the regulator and the rectifier.  Bin the old regulator but hang onto the the old rectifier,  it can be useful for someone if it works ok.  If you mount it in the same position as the old rectifier it'll get enough airflow to keep it within temperature parameters.

[billdn]

Success!👍 new rectifier/regulator fitted and all works fine! Thank you one and all for your patience , knowledge and advice! Even found a secure mounting spot!