battery went dry

Sorry, yes R/R does mean Regulator/ Rectifier.
Also I wasn't clear enough about your Brown wire, check with Key on Engine OFF. Read across your Battery terminals, get that reading. Then across the brown wire back to battery negative. Your difference should be slight,< .5v, or you will get a overcharge. If that all checks out then MAKE SURE that your battery is good before condemning the R/R assy. This may also give the R/R false info thinking the battery is still low. You may want to take it and have it tested, they hate being dry, causes the plates to short out when dry and you load the circuit. If this all checks out, then R/R may need replacing, but make sure of the system integrity first before throwing parts at it.

Motor Head wrote:

Sorry, yes R/R does mean Regulator/ Rectifier.
Also I wasn't clear enough about your Brown wire, check with Key on Engine OFF. Read across your Battery terminals, get that reading. Then across the brown wire back to battery negative. Your difference should be slight,< .5v, or you will get a overcharge. If that all checks out then MAKE SURE that your battery is good before condemning the R/R assy. This may also give the R/R false info thinking the battery is still low. You may want to take it and have it tested, they hate being dry, causes the plates to short out when dry and you load the circuit. If this all checks out, then R/R may need replacing, but make sure of the system integrity first before throwing parts at it.

I would say check it while it's running, that way ignition currents will be flowing. It needs to have full current in the wiring to show the voltage drops we're checking for.

A faster, and more accurate way to do it is to put the red meter lead on the battery positive post, and the black meter lead on the brown wire. Now the meter is telling you the actual voltage difference between battery and sense line. That's what we really want to see. Hopefully it's less than about .5v. This checks the positive side.

The next check is to put the red lead on the regulator's ground connection and the black lead on the batery's negative post. That tells you the actual voltage drop through the ground lines. That should hopefully be as cloas to zero as possible.

otakar wrote:

You should be getting about 14.5V out of the regulator. If you are getting over 15V, the regulator is bad. Don't worry about a "RR", you don't have one. You have two separate units. The little silver box is your regulator.

For some reason I was thinking that we were talking about a KZ900 before I made this posting. It would really help if we all knew what bike is in question. There are different specs and completely different units on different bikes.

ok,,,i'll check brown wire with key off,

The Shepherd wrote:

ok,,i found a silver metal box under the battery box,,,,I'll take it for the regulator,,,,it has a green plug at the end under the left side cover,,,,,male plug shows 4 wires and the female plug shows 5,,,, one wire is brown at the male plug,,,,when i checked voltage a 4000 rpm i got 16.8 volts at battery and 16.3 volts at the brown wire,,,,these volts climb slowly as time goes by,,,,,but either way I'm above what it should be at both points....Is the silver box under the battery box a voltage regulator

I didn't see this while I was posting earlier.

As Otakar said, please put the bike model and year in your signature so we know what we're dealing with.

So you have one wire unconnected? 4-on male...5-on female...means one is not connected, right? If the regulator only has 4 wires and one is the brown sense wire, then it's missing a wire or the regualtor is not factory. In either case it won't work with factory harness using brown as a sense line.

If it has 5 wires and one is brown, then it's ok. In that case, check my post about the brown wire... bike should be running, but with new/good battery.

But, again, at this point we need to know exactly what you have... bike... regulator...rectifier. Pics would help if possible.

1976 kz900 not the LTD,,,,, key off, battery voltage 13.5 volts,,,,,,,,using the brown wire from voltage regulator as negitive and positive at battery voltage 13.5 volts,,,,,match,,,,confused why i use brown wire at regulator for negitive but that's ok,,,,,,,,,,battery has started the bike a number of times now,,,i think it's good,but i'll get it checked,,,,,It seems to be time to order a new regulator,,,,,thanks all for all your help,,Pat

This combo unit resolved rec/reg issues for me (many years ago, and still going strong).

Click here > www.z1enterprises.com/detail.aspx?ID=1873

Good Fortune!