Non charging bike KZ650

[Oggers]

Gents

Newly purchased 79 KZ650 I think has a charging problem. Battery read 12.2V but died to about 8V after a run - lights are on which does not help. Charged battery up again on charger to 12.3, started bike, revved it, no increase to voltage at terminals.

Suspect 1 - Regulator and possibly rectifier. I believe a reg/rec combined unit can do the job from a Superdream? Clues welcome as to how to fit/wire in

Suspect 2 - Bad earth somewhere

Suspect 3 - The old battery is not taking charge - but then it did charge up off the bike?

Suspect 4 -Alternator - but let's no go there yet!

Help much appreciated!

[KWACKERZ1]

Got the same issue with mine and have just purchased a rec reg from M+p, superdream ones are 3 phase some z650''s are single phase. My B is so you'll need the right type.

Check the AC voltage output from the wires on the alternator output plug. (single phase is two wires only)

Then check output from reg rec.

[Oggers]

Bit if an update- the bike actually has a Shingenden reg/rec fitted. 3 wires from the alternator in, one red/white out. I have measured the voltage acorss the red/white to earth. Idle is 7V, and at 4000 rpm is 11.5 V - so I assume not enough ooomph - for want of better words to charge. Still no rise in voltage across the battery - that stays at around 11.8V.

I assume the voltage acroos that red/white output from the reg/rec should be higher at 4000 certainly - and thus charge the battery - though I cannot see why it didn't charge it when it effectively died to 8V?

Thoughts very welcome.

[moizeau]

It's very simplified but have a read of this. A workshop manual goes into more detail.
https://www.denniskirk.com/learn/how-to ... motorcycle

[warren3200gt]

You should be getting 13+ across the poles at idle Oggers. The manual shows how to test your alternator output. If that checks out ok then is the reg rec adjustable? The the early seperate reg rec set ups were adjustable with a bit of fiddling but dont know about your combined unit.

You might be able to get some clues here https://kzrider.com/service-manuals 77 and 81 available or here for another version http://www.jarlef.no/Kawasaki/Series/Z/ ... 0files.htm

[Oggers]

Gents

This is all very useful informantion - very many thanks. Reg/rec is a combined finned unit and non adjustable. I too am thinking I need much more at idle and basically the thing is u/s. I will also check out the alternator as per the simple guide.

As I say the output/feed red & white wire from the reg/rec only gives out about 7V across earth at idle. I am assuming this is an indicator that the reg/rec is goosed.

Again, many thanks.

[Oggers]

Gents

Quick Q - Reg/rec has 4 wires for the single phase alternator. Two yellow wires to the stator wires, red/white for the feed and a black .

Is the black the earth for the reg/rec?

If s,o I may have a bad earth here - which may account for the problem.

Many thanks

[warren3200gt]

https://diagrams.kz650.info/wiring/WiringDiagrams.htm

[Oggers]

Warren

That wiring diagram is superb - very many thanks. Will also come in very handy during the restoration. The Haynes diagram is total pish. Tested the now confirmed earth wire - closed circuit to earth, so all seems OK there. Bought a second hand Shingenden reg/rec off Fleabay so hoping that will fix it. if not - could be alternator!.....

[warren3200gt]

Why not test the alternator in the mean time?

[Bill P]

Oggers if you go to www.Kojaykat.com they do superb blown up wiring diagrams for Kwaks
enjoy the build

[Oggers]

I have done very basic checks on the alternator - seems fine. I know there are more detailed tests that can be done, but I'll cross that bridge if the spare reg/rec doesn't solve things. Not entirely sure how you fix alternator issues unless the problem is obvious. I can fix a Lucas dynamo though!

[warren3200gt]

Fingers crossed for the reg rec then. If it comes to it you could always run a dynamo off the front wheel like pushbike days. (Just dont slow down or it'll get very dark very quickly. )

[Oggers]

Gents

Just a to say I think this is now solved. Essentially I changed out the reg/rec and no difference. I then proceeded to the alternator and the further tests made no sense. I then moved to pull the alternator to take a closer look and found the two yellow wires and the bullet connectors coming from the base of the alternator. I had actually checked these with a cursory glace beforehand and all seemed well, but this time I gave them a waggle - and would you believe one of the connectors came apart! Reconnected it properly and we now appear to have a charging bike. Two things that threw me.

The bullet connectors "looked" fine. Clearly the one that was loose was just held in place by the clear plastic shroud, but not actually connected. lesson learned. Waggle connectors to make sure!

Secondly, there is still a charge even if one wire from the stator is disconnected. That led to me suspecting other things.

However all now seems well, but one further point. I too am used to seeing 12 to 13V at idle across the battery, but in my case it is more like 11.5V. Mine is however the US version (KZ) with the lights permantly on which of course draws a load, so I wonder if this is normal for the US version. It does get up to 12.2V at 3000 rpm and above, so just keeping things charged. A new battery may improve matters I guess......

[KWACKERZ1]

Good result then, eventually Your probably right about the 11.5 with the lights on .

My personal grip is those red and blue bullet connectors people use, there were crap new and 20 years on they are worse

Enjoy the bike