Yama Seca II electrical woes

[don07tncav]

One of my buddies had his voltage regulator just changed because his battery would go flat very-very quickly.

He just got the bike back and his first ride with the new battery went flat again.

Here's what he's had done:
Changed out voltage regulator/rectifier
Put in new battery
Put in new plugs
Pulled/checked all fuses

My thought that his wiring might be grounding somplace. What other things should he be checking?? I told him that I'd drop this here and ask you gurus!!

His bike is a 1992 Yamaha Seca II

Thanks for any and all suggestions!!

[randy]

Sure,

Here you go:

Pull all of the fuses. Turn on the ignition and using a meter or a test light identify the hot side of the fuse. Turn off the ignition.

You need to test between the other side ( cold side ) of each fuse to ground (frame) using a multimeter set on Ohms X1 or X10. The shorted circuit will show a very low resistance to ground.

That will just get you started on the right circuit, then you can continue tracing through the wire harness to find the exact location of the short.

[John]

A quick way to test for a draw on the system is to use a test light . Remove the Neg battery cable, and hook the clip of the test light to the battery post and then probe the cable end. If the light illuminates then there is a draw. If not, then no draw. If there is a draw, then start pulling fuses one at at time until the light goes out. Then start inspecting everything that is in the circuit controlled by that fuse. If no draw is found, the check the output voltage and the regulated voltage of the alternator. Battery voltage should be around 12.5 and regulated voltage should be around 13.5 to 14.5 volts.

[randy]

Right, John, that's a great way to troubleshoot a drain when the bike is OFF, but his trouble is with the bike ON. That's why I suggested that he pull the fuses first and check resistance to ground.

[John]

If there were a problem with the alternator or the regulator, even though it is new wouldn't it show up even if the bike is off? I know you are better with the 'trons' than I am, but I know that a lot of Ford alterators w/ internal regs can drain a battery when the ignition is off, and I thought that may be the case here.

[don07tncav]

Thanks for the replies gents, he's monitering the thread and hopefully will have time to try some of your ideas in the next day or so.

Like me, he knows very little about bike repairs and as usual you've given some simple to try ideas!

[randy]

Waddya say, Don? Does the battery go flat when the bike is on or off?

Or both??

[don07tncav]

Randy, I'll ask him in the morning unless he registers and answers tonight!