bike discharging problem...again!

redl1nerpm · #1 (**permalink**) 10-29-2007

edited: please scroll down to the #9 post to see how to test your system if your wondering..

So as some of you may or may not know my bike was discharging. Basically I could go for a 15 minute ride and the gauges would blink, then go off and I would have to recharge the bike. After getting to the stator it looked old and in need of replacement. The rotor looked pretty nasty too, so I replaced both the rotor and stator (see write up here: http://www.triumphrat.net/triumph-su...ghlight=stator). The parts did have some miles on them but looked mint and were off a newer S4 (higher amp output). I also installed a brand new battery.

Since then I installed an HID kit which supposedly utilizes less power than a conventional bulb. I then rode the bike for 3000 miles over the past 2 months or so. Today on my way home, I look down to realize my gauges are blank. I come to a stop off the highway and the gauges starting working again for a moment, but once I started riding again, they blinked and shut off. I got home and sat in the driveway but they didnt come on again. I turned the bike off, and tried to start it but of course it was too dead.

I removed the HID kit and installed the stock bulb. I put the battery on a charger for about 5 minutes and started the bike up. After it got warm enough, the fan kicked in and the gauges went off again.

Im now charging the battery for a longer period and going to ride with the stock bulb.

Im really hoping the new stator is not bad again.. Maybe the rectifier is bad?? Anyone know the symtoms or other possible problems?

TheCobraMan · #2 (**permalink**) 10-29-2007

i had a problem with mine, replaces a few stators. check the connection on the tail section near the rectifier. mine was corrodid on the ground side. if they don't get a good ground they will burn themselves out in a hurry. I had my stators rewound at custom rewind. was like $85. I had one done and pinched a wire in the housing and didn't know it and burned it up. put a new one on it and a fresh battery and havn't had any problems. if you have any questions feel free to contact me.

redl1nerpm · #3 (**permalink**) 10-29-2007

i did some testing and found the following:
Charged the battery to 12.7 and started the bike. It immediately started going down. After a few minutes the battery was around 12.4 while the bike was running. The rectifier showed just below at about 12.35. After a few more minutes of it running the rectifier showed 11.95 and the battery at 12.0.
I then tested the wire coming out of the stator. THIS PART IM NOT SURE IF I DID CORRECTLY WITH MY VOLT METER. I turned it from the DC setting (how I got the numbers above) to the OHM setting at 20k or 200k or something. It was showing 15-16 coming from one of the wires out of the stator while it was still plugged into the bike (I stuck the little needle in the connector with it still connected).

So was the second part the correct method (OHM setting) for the stator? And should it have read around 30? If not how do I test the amps from the stator? I tried it on the DC setting but got nothing.

redl1nerpm · #4 (**permalink**) 10-29-2007

local guy explained how to test the stator, rectifier and battery:

"1) Charge the battery overnight (7~12 hours), not to exceed 24 hours. You may exceed 24 hours if you are using a ‘smart charger’.
2) Disconnect charger and allow battery to stand for 30 minutes. Check the battery voltage with a digital voltmeter. The voltage should be around 13.3~13.5. If the voltage is less than 12.5, replace the battery.
3) Install known good battery into bike and start engine. After warm-up, bring engine speed up to 5000 rpm and measure the battery voltage at the same time. The voltage should be about 14~14.5 volts. If the voltage is greater than 15, the problem is most likely the rectifier/regulator. If the voltage is less than 13.5, then it’s either the alternator (stator coil) or the rectifier/regulator, or possibly even both.
3a) SIDE NOTE: A problem that seems to occur with sportbikes rather frequently is the 3-terminal stator coil connection fails and the resultant heat from the I*R drop melts the connector. In addition, the red-wire contact on the rectifier/regulator connector also has a history of oxidation/corrosion. Be sure to check these!
4) To check the stator coil (alternator), measure the AC output voltage between all three stator leads (1 to 2, 1 to 3, 2 to 3). The AC voltage should be at least about 10 volts AC for every thousand of engine rpm. Test the AC output voltage up to about 5000 rpm."

Will · #5 (**permalink**) 10-29-2007

Thanks for posting what he said. I didn't know you should get 10v per 1K rpm or so.

redl1nerpm · #6 (**permalink**) 10-30-2007

Originally Posted by Will

Thanks for posting what he said. I didn't know you should get 10v per 1K rpm or so.

yeah and he said the real important thing with the step is that each of the three are within 10% or so of each other. If ones not, that means one of the big electrical things on the stator is bad.

TheCobraMan · #7 (**permalink**) 10-31-2007

unplug the stator and check for continuity to ground on all 3 legs. if they show any at all it's junk and needs rewound or replaced. should show an open circuit.

Billybob · #8 (**permalink**) 10-31-2007

Guys, thanks for an informative discussion!

redl1nerpm · #9 (**permalink**) 11-01-2007

thanks to Sam Ferris on a local forum for explaining this to a guy who knows little about electrical system tests. But heres what you need to do if your having a charging problem:

1) Charge the battery overnight (7~12 hours), not to exceed 24 hours. Being a bike you should charge at a very low rate, like 1-2 amps. You may exceed 24 hours if you are using a ‘smart charger’.
2) Disconnect charger and allow battery to stand for 30 minutes to an hour. Check the battery voltage with a digital voltmeter. The voltage should be around 13.3~13.5. If the voltage is less than 12.5, replace the battery.
3) Install known good battery into bike and start engine. After warm-up, bring engine speed up to 5000 rpm and measure the battery voltage at the same time (DC or DCV setting on your voltmeter). The voltage should be about 14~14.5 volts. If the voltage is greater than 15, the problem is most likely the rectifier/regulator. If the voltage is less than 13.5, then it’s either the alternator (stator coil) or the rectifier/regulator, or possibly even both.
3a) SIDE NOTE: A problem that seems to occur with sportbikes rather frequently is the 3-terminal stator coil connection fails and the resultant heat from the I*R drop melts the connector. In addition, the red-wire contact on the rectifier/regulator connector also has a history of oxidation/corrosion. Be sure to check these, clean them and use new dielectric grease!
4) To check the stator coil (alternator), measure the AC (AC or ACV setting) output voltage between all three stator leads (1 to 2, 1 to 3, 2 to 3). To do this unplug the connector, start the bike and test each pair with your voltmeter. The AC voltage should be at least about 10 volts AC for every thousand of engine rpm. Test the AC output voltage up to about 5000 rpm.

redl1nerpm · #10 (**permalink**) 11-01-2007

my own results:

ok so started the bike with a full battery. With the connector unplugged I tried each wire set on the ACV setting (while it was running) at about 2100 rpm and got:
1-2: 1.55
2-3: 1.60
1-3: 2.00

I tried changing the ACV setting from 20 to 200 to 2000 etc. but it just gave me more numbers after the decimal (i.e. 1.5 to 1.55 to 1.558 etc).

Next I turned the bike off and with the key out of ignition and the connector plugged back in I tried two things:
First put red needle to each stator connection and black needle to battery negative and got: .7 for each wire on the ohm setting. When I switched the OHM setting to the one which beeps, it would beep everytime I touched the batt neg. It would always spike to a high number, but then fall to .7

Then I tried the same only using a bolt on the chassis instead of the batt neg. This time it seemed to always show about the same .6 or .7, and it would still beep if on the sound setting when I touched the bolt. It would always spike at first to a high number, than go down to this number for each.

Sam explains:

I suspect the .6~.7 reading you were getting is unfortunately the series/parallel resistive summation of all three stator coils in respect to ground. This means the stator coil assembly is somehow connected/shorted to ground. This is most likely the cause of your charging problem.

The 'jump' in the reading you were seeing is most likely caused by a capacitive 'charge' built-up from the ohmmeter into the recitifier/regulator.

Both the jumping meter and the '1' indication are what I would expect to see.

My conclusion is your stator coil assembly is shorted to ground and needs replacement.

Looks like I need a new stator now, this time I wont get a used one...