KZ550C LTD Charging Issue

I have recently aquired a 1980 KZ550C1 Ltd. I got the bike running like champ, although the Kerker 4into1 exhaust is extremely loud.

The only issues that I have is with the charging system and possibly a week starter. I am only getting about 12.5 volts across the battery when the bike has warmed up. Whet it is cold I usually get around 13.5. I downloaded the troubleshooting guide from Electro Sport. I get to the 3rd or 4th step in the chart when I find that I have a .6 voltage drop between the switched brown wire that goes into the Regulator/Rectifier. (according to the chart, more that .2V is considered bad). I have checked and rewired all of the connections on the entire bike. Here is the thing that puzzles me, when I disconnect the headlight the voltage drop goes to .14V and the battery measures 14V across the terminal.

I hope the weak started is related to the charging issue.

I really don't have any more hair to pull out. Any help would be apreciated.

Brandon

When you say you get 12.6v across the battery when the bike is warm, but 13.5v when it is cold, are you saying that when you have the bike warming up (cold) and it is probably running higher rpm's than when it has warmed up and is idling...??? It should be running a bit higher voltage across the battery when the rpm's are higher. And when you drop off the headlight, which sucks quite a bit of current, you would or should see some small spike in your voltage, I would think. You mentioned a weak starter. Are you sure it is weak? Just wanting to clarify a bit so someone with more experience might be able to help!

Oh yeah, sounds like we have the same bikeB)

Post edited by: fergyfer, at: 2005/10/12 15:03

I'm having a similar problem w/ my spectre 1100. I opened the stator cover and found that the rotor cut through the stator wire casing esposing the wires to the oil. Have you looked in there lately?
Hope this helps
~joe

At idle when the bike is cold it measures about 13V across the battery terminals. At about 4K RPM I am getting just over 14V. After the bike has had a chance to warm up, the voltage drops to 11.8V at idle and 12.5 at 5K RPM.

I am not sure if my starter is weak or it is due to the charging issue. It will not turn the bike over when the bike is hot.

That is interesting. Sounds temperature related, but what would be affected by the temperature of the engine? Coils? Regulator, or stator?? Is yours electronic ignition or points? Maybe a bad connection somewhere that opens up a little when it heats up... I understand you pulling out your hair....

Have you opened up the fuse box and checked for any corrosion on the fuse ends and clips? It's possible that you also have other connections that need cleaned and tightened.

I have the same problem with my 77 kz 650. The bike is getting about 13.5 volts at 1600rpms but the voltage will drop as rpms increase. Could this be the cause of bad throttle response, fouled plugs and running rich? The contacts on the regulator look bad so I will replace it but wondered if this could be the cause of other problems.
Thanks

Since the engine turns the rotor on the alternator, an increase in rpm's should increase the voltage output, but it should have nothing to do with fouled plugs, running rich etc. If your voltage regulator and alternator are working correctly, an increase in engine rpm's should raise your voltage, no matter how your engine is running.

zippoman wrote:

I have the same problem with my 77 kz 650. The bike is getting about 13.5 volts at 1600rpms but the voltage will drop as rpms increase. Could this be the cause of bad throttle response, fouled plugs and running rich? The contacts on the regulator look bad so I will replace it but wondered if this could be the cause of other problems.
Thanks

Yes, when ever the voltage drops to 12vt or less the coils can't produce a good strong spark. Here is something to try. Have your battery fully charged and give yourself access to the rectifier. Start the bike and let it run, after a few minutes see if the recttifier is hot.It maybe warm but should not feel to hot to touch. Also look to see if the nuts on either side are lose or have been turned. The coating on each nut should be intact.You may need to replace it.

Post edited by: walt, at: 2005/10/14 10:15

double check your battery. How old is it? Does it have enough water/acid to cover the plates. If not that can effect how and if it charges correctly. The batt is only good for about 2 yrs +/- You can make them go longer, but you might be needing to charge them much more frequently. The volts should cycle a bit when the RPMS are up high so you do not over charge the batt (regulators job)