Alternator Trouble?

[John OoSTerhuis]

You don't have to run the ST to check out the three stator windings. Do the simple "Alternator Inspection" check shown in the Honda Service Manual, page 17-6 in mine. Simply put, disconnect the red 3P and check for continuity to ground of each of the three yellow AC lead wires at the stator side of the connector. Continuity shows that winding shorted to ground = replace the stator (and possibly the VRR), or bite the bullet and upgrade. HTH

I don't think the mods will allow me to post a scan of the manual page here. Email me if you need one.

With no extra loads your battery should read over 14V at anything over ~3K rpm.

Regards, John

 

[bdalameda]

I have never had good luck doing the ground check on stator windings as is shown in the manual. I have had many stators check good this way but will break down when the engine is running due to heat, vibration etc.. The running check is far superior and you will almost always get a good test. You can also have degraded insulation on windings that will not show up in the static test and the winding will still produce power but will be imbalanced with the other windings. The running test will show this weakness and one wire combination will read lower and this is a good indication that the stator is going to fail. A stator in this condition can also ruin the regulator rectifier.

Dan

 

[LoSTBrit]

So are 28A alternators desirable in the UK?

Anyone in the UK want to do an air for oil swap ?!

 

[John OoSTerhuis]

I have never had good luck doing the ground check on stator windings as is shown in the manual. I have had many stators check good this way but will break down when the engine is running due to heat, vibration etc.. The running check is far superior and you will almost always get a good test. You can also have degraded insulation on windings that will not show up in the static test and the winding will still produce power but will be imbalanced with the other windings. The running test will show this weakness and one wire combination will read lower and this is a good indication that the stator is going to fail. A stator in this condition can also ruin the regulator rectifier.
Dan

Excellent points, Dan. The static continuity checks are the quick-n-dirty first-step. But it's pretty definitive if any of the leads do in fact fail it, as many STriders have found out over the years. And yes, there's not much worse than an intermittent electrical problem.

I know of the AC output check but darned if I can find it in my ST1100 manuals at the moment... is it in the Honda Common Service Manual...(?) To be clear... you set the meter to AC, start the ST and then touch the red probe to one yellow lead on the stator side of the disconnected 3P and then the black probe to the other two yellow leads at this connector in turn, repeat for all combinations... is that correct? And do you have the actual output spec/rpm? TIA!

I'll add a additional 28amper diagnostics point here: unless you use the exact multimeters spec'd in the Service Manual, you'll get erroneous/useless readings doing the "Regulator/Rectifier" check shown in the manual. As none of us have these particular meters, controlled substitution with a known good VRR is our only solution/course of action (I have loaner test VRRs for that purpose).

John

 

[bdalameda]

Yes that is how it is done. Any two of the three yellow wires will show AC output. There is a spec but I have found that if you are in the 50-80V AC range depending on rpm the most important part of the check is that you have the same output from any two of the three yellow leads. If all combinations of two wires show the same output, you are good to go. If any combination of two wires of the three show different output this means one of the windings is suspect. I am not sure if this check is in the Honda Common manual. It is the same check I use on virtually all Japanese motorcycle alternators regardless of brand, as they all use this same three wire combination from the early 1970's through to today.

Dan

 

[GSXR]

OK, I've fitted a new battery and done some testing and here are the reuslts:

Battery unfitted: 13.18v
Current leakage ignition off: 1.1 mA
Voltage at Tickover: 14.25v
Voltage @ 5000 rpm: 14.5v
Voltage Light on @ Tickover: 13.6v
Voltage Lights on @ 5000 rpm: 15.1v (??)
Harness @ VRR Red/White to Earth: 13.18v
Harness @ VRR Yellow to Yellow 0.0 Ohm
Harness @ VRR White to Black 3.5 Ohm
VRR Pins Red/White to Yellows: 28.1, 28.0, 27.1 K Ohm
VRR Pins Red/White to White: 143 K Ohm
VRR Pins White to Yellows: 80.8, 80.5, 80.2 K Ohm
Alternator terminals @ 3 Pin & 2 Pin Plugs Yellow to Yellow all combinations: 1.0 Ohm
Alternator terminals @ 3 Pin & 2 Pin Plugs White to Black: 4.0 Ohms

That's al the testing I did so far and I think it all seems to be OK with the exception of the Regulator pin resistance readings. I understand that these are virtually impossible to measure to the correct spec anyway?

I really wish now that I had run the bike and checked the voltage accross the yellow alternator terminals but I was kind of concerned about shoving my probe into 80 Volts!

It's certainly been a learning process and I'd like to thank all those that have replied to the thread and I promise I'll try to leave you in peace for a while now!

I'll keep you posted if the new battery gives up the game...

Thanks a million guys,

Ian.

 

[Hound]

Sometimes it's easy to convince yourself that the battery is ok and that the problem is something much more sinister and expensive. Then you get a new battery, everything is ok again, and you wonder how you missed the obvious. :

Hope I'm not speaking too soon!

 

[bdalameda]

Looks good to me.

 

[alphafang]

Voltage Lights on @ 5000 rpm: 15.1v (??)
Looks very good to me???? maybe not, overcharging and frying the battery??

 

[GSXR]

Voltage Lights on @ 5000 rpm: 15.1v (??)
Looks very good to me???? maybe not, overcharging and frying the battery??

I must admit to being a bit surprised by that result - higher voltage than with lights off but I checked both readings again and got the same result.

Maybe only time will tell...

 

[bdalameda]

Missed the 15.1V reading - It does seem a bit high. Probably not a problem for the Gel battery but a conventional lead acid battery may get a bit hot and lose water. I would double check this reading but it definitely looks like your alternator winding are OK

Dan

 

[stoker]

Anyone provide a part number for the police voltage regulator? ST1100!

 

[ESB]

YEA - +1 for the Police VRR - Would like to get 1 of those - Need to find 1.

 

[BuddingGeezer]

Missed the 15.1V reading - It does seem a bit high. Probably not a problem for the Gel battery but a conventional lead acid battery may get a bit hot and lose water. I would double check this reading but it definitely looks like your alternator winding are OK

Dan

15volts is the upper limit according to service manual specs. My conventional AGM battery lasted me over 3 years @15.2 volts and it was 3 years old when I bought the bike. 6 years at 15 volts, I'll take it. The voltage finally climbed to over 16 volts. due to line voltage(11volts) loss at the black wire on the VRR. A bypass relay from the battery to the black VRR wire brought the running voltage down to 14.5 volts.

 

[ST1100Y]

Anyone provide a part number for the police voltage regulator? ST1100!

31600-MZ9-901, rectifier assy., regulate. Further required: 31605-MZ9-900, stay, regulator rectifier and 31606-MZ9-900 plate, regulator setting (those two build the bracket to hold the P-spec VRR on the footrest plate), then 2 pcs bolt flange 6x16mm and 2 pcs M6 hex nuts. With two headlight bulbs engaged (2x 55W) the P-spec VRR is rated for 90W accessory equipment (like 3 patrol lights, etc...). Due its diecast heat-sink the P-spec VRR is a rather large component, possible that someone would need to move any additional relays or fuse-boxes in that area (no problem with OEM wiring though). The P-spec ST1100 also features a 55A fuse (as seen on the post '96 model with air cooled 40A alternator), feeding/protecting starter supply and mains power.

 

[tkhelm]

Any two of the three yellow wires will show AC output. There is a spec but I have found that if you are in the 50-80V AC range depending on rpm the most important part of the check is that you have the same output from any two of the three yellow leads. If all combinations of two wires show the same output, you are good to go.
Dan

I thought I had solved my problem but I'm back to seeing little to no charging while riding, according to both my voltmeter and my multimeter at the battery terminals.

I did the yellow wire AC check above and It shows only about 20V (AC) at idle speed and about 40V at 2000rpm. I'll need a third hand to turn the throttle to check higher rpms but I'm wondering if these results are already too low and pointing to a problem. What is the range of rpms I should be checking? All three yellow wire pairs give the same result, so at least that's good.