cb550 charging system fault

[bigmockuk]

hey everyone,ive had this cb550 k3 (77 plate) for like 10 yrs ive put up a few posts in the past about it,well,thats me finally got my full licence (long story lol) but i had the chance to get this bike cheap at the time so grabbed it,was great to finally get it out on the road and ive done bout 130 miles,problem is the battery was badly heating up! i got an upgraded reg/rec years back and it never worked,got a new one delivered today....and it doesnt work either.ive been using the old regulator to fire up the field coil and charge the system,obviously its too high but no matter what i turn it down to,the charging wires from the rectifier heat up a lot!i renewed the main harness and the sub harness a while back but feel the wires on the subharness (the ones that are overheating ) are so flimsy compared to the old heavier originals,could this be the reason ? any thoughts anyone has would be appreciated thanks

[Bryanj]

Too small wires will overheat but you need to do some testing.
With ignition on put neg lead of multimeter to neg of battery then with pos meter lead check volts at pos battery and black wire at reg, any more than0.5 volt difference you have a problem

Do this with kill switch TURNED OFF

[bigmockuk]

thanks bryan i`ll do that in the morning.any idea why that new reg/rec didnt work? could it have blown instantly?

[Bryanj]

Split second of incorrect wiring will blow it

[Gromitdog]

Hi Big Mock
I had a charging problem on Mutely the Honda after I did a wiring loom replacement It took a couple of hours to find the fault and it came down to the  connector on the stator it has a slight long spade on the original loom. Just carefully took it apart then re crimped.   -    jobs a goo-den 🤗

[bigmockuk]

i`ll check for that too! cheers

[bigmockuk]

Hi Bryanj,my battery was pretty low when i went down to the bike this morning,it was reading 11.88 at the battery and 11.18 at the black source wire so i`ll have to charge battery to get a true reading.on a brighter note,i found that one of the yellow wires and a red  wire on the sub harness was half melted,these wires are very flimsy thin wires so i rewired using a heavier gauge wire,i did all 3 yellow wires,both red and green wires on the subharness and set regulator to give out 13 volts,none of the wires are overheating so i`ll see if i can set reg at 13.70/80 without wires overheating and i`ll be happy at that running with lights on.

[Bryanj]

When the battery is charged test for battery voltage at the white wire to field winding, should be same as black at reg and batt pos, ignition on and kill switch off, again white wire should be within 0.5 v of battery.
Report back

[bigmockuk]

cheers will do!

[bigmockuk]

Bryanj,put battery on a quick charge this morning while i did other things,got it into the bike and ignition sw on,kill sw off,lights off and i got 12.69 volts at live battery,12.69 at black source wire and 12.69 at reg terminal the white wire connects to.Once i connected the white wire i got 11.58 at both the black and white terminals and a decent spark too at the white terminal as the wire came into contact with it.i went for run about for a few local miles and wires are only slightly warm as opposed to what they were like before i changed them.
i`d like to know what that green electrical bar is thats connected to the regulator,that fair gets warm!  i take it i hope that thats normal for that?

[Bryanj]

Its a resistor and supposed to get warm, in Ash's dropbox is a description of how the 3 phase charging circuit works but basically you can have zero charge
Half charge
Full charge
Depending on state of battery voltage

Look up the Honda service letter

[bigmockuk]

i`ll give that a read thru cheers