Looks like my VRR may be dead....

[stevewp]

Hi all,

new here but have had the Pan for a couple of years. This morning on my way into work, I noticed that it's not charging well. Normally, the voltmeter sits happily around the 14V mark, as you'd expect. This morning - below the 12V mark. Not great. It was slowly getting worse as I went on (I ride about 35 miles each way to work) so I knocked off all ancillaries and headlights. It managed to stay steady at a little under 12V that way. Would dip under braking but pick up again on acceleration.

I've done alot of digging on this site through the morning and found some measurements to check against on this thread: https://www.st-owners.com/forums/showthread.php?132697-VRR-voltage-ST1100-28amp . So, I've taken a little time out of work to see what I get.

VRR readings:

Yellow->R/W should be 7.5 kOhm actually 6.8 MOhm
White->R/W should be 60 kOhm actually 6.8 MOhm
White->Yellow should be 28 kOhm actually 8 Mohm (x2) and open circuit for the other

Alternator readings:

Yellow->Yellow should be 0.4 Ohm actually 0.1-0.2 Ohm
White->Black should be 0.4 Ohm actually 2.3 Ohm


This is an ex military police bike, so I'm aware that things aren't always as on most factory Pan's. Particularly, I believe there is some sort of uprating on the charging system, though I'm guessing (from all the research I've done today) that it's still only a 28A alternator. However, the alternator readings look ok-ish to me whereas the VRR readings looks horrific.

So, am I right in assuming the VRR is shot, or is further investigation required?

It seems to bump alright so I'm hoping I'll make it home this afternoon..........

 

[stevewp]

Has nobody got any thoughts?

 

[2turbos]

White->R/W is not spec at 6.8 mohm. Can you check a new one for comparison?
Also, do the usual, check the connectors for excessive resistance.
Have you done the "Red wire Bypass" at the connector plug?

 

[John OoSTerhuis]

Steve, first thing first... you don't indicate the part of the Alternator Check in the Honda Service Manual that checks to see if any of the three yellow AC leads at the red 3P connector show continuity to ground. If one or more do, your stator is shot. The VRR may or may not be fried. What multimeter are you using to check the VRR? All the meters I've heard of folks trying have not gotten reliable ST1100 VRR readings.

John

 

[stevewp]

The red wire has already been done by someone previously, following melting of that part of the connector. So there's definitely been an issue before. The rest of the connectors on that big block don't look great, so I'm going to do something there, plus the red connector doesn't look great either.

The other thing I thought I'd try (now that it's home and charged) is to measure the volts across the yellows when the bike is running. Am I right in saying they should be circa 50Vac?

 

[stevewp]

Hi John. I don't have the service manual so I'm somewhat reliant on the info I can find on here. I'll check the yellows to ground, though I think I may have checked and found they were ok. I'll test again though.

I'm using a Fluke but also have an Avo at home, so will compare with that

 

[ST1100Y]

Well, I don't know about the type of multimeter used, nor if measurement errors are conceivable...

Taken your results on the VRR I would believe its shot... still: compare with a working one to exclude any misdiagnosis...
Also explain which type of VRR is installed: the small, "civil" one (black, cuboid, sealed with black resin), or the larger, P-spec type with the Aluminium heat-sink.

Main windings of the stator seem OK (Y/Y can be 0~1.0 Ohm), but the reading on the "control winding" seems off, W/B should read 0~0.4 Ohm...

I'd also check all crimp connectors, prongs and cables for signs of corrosion/overheating to eliminate any culprits from that side (measuring and operational)

With the currently avail data I'd suspect a cascading error, cabling/winding failure took out the VRR and/or vice versa... but I'd dig further and eliminate any false trails and circle down on the true cause of error...

By themselves the 28A alternator and its VRR are reliable, its takes outside influences to cause damage; increased resistance due to corrosion on connectors, long-term overload conditions...

 

[stevewp]

Ah yes, good point - it's the aluminium one. Sadly, I don't have a known good one. I'm loath to spend the money buying one before being more certain of the issue.

Definitely I'll go over all the connectors and likely replace them all as, in general, they don't look altogether healthy.

My main hope is that it's not the alternator itself. Anything else I can sort without too much issue.

 

[John OoSTerhuis]

Hi John. I don't have the service manual so I'm somewhat reliant on the info I can find on here. I'll check the yellows to ground, though I think I may have checked and found they were ok. I'll test again though.

I'm using a Fluke but also have an Avo at home, so will compare with that

Thanks. Here's the static (engine off, red 3P disconnected) check:

The next check would be the dynamic AC check between the three yellow leads.
edit: If you're going to keep the ST you should get a service manual. These forums are really no substitute for a proper manual, and most folks offering to help hope that the member asking for help has one. IMHO

Good luck.

John

 

[stevewp]

Thanks for that info John. I'll definitely go through those. And yes, AC check was originally next on my list. Am I right to expect circa 50V ac?

 

[ST1100Y]

Ah yes, good point - it's the aluminium one.

P/N 31600-MZ9-901 then...
http://www.cmsnl.com/products/regulate-recti_31600mz9901/#.VSFV_5O4Jgs
You might opt for an after market though...
http://www.ebay.co.uk/sch/i.html?_odkw=31600-MZ9-901&_from=R40&_osacat=0&_from=R40&_trksid=m570.l1313&_nkw=ST1100+regulator&_sacat=0

I believe that the guts of both, civil and P-spec VRR are identically, the later just has a different housing, facilitating increased cooling efficiency for the increased load due patrol lights and radio...

Definitely I'll go over all the connectors and likely replace them all as, in general, they don't look altogether healthy

Given your location, not astonishing ;-)
That brine during winter use is anything but good for any automotive...

My main hope is that it's not the alternator itself.

Well, that winding can trick one...
On the '94 I'd throughout refurbed, all initial readings & measurements were OK, but the bike went dead like 300ft from the MOT station...
Stator shorted to ground...

 

[John OoSTerhuis]

Thanks for that info John. I'll definitely go through those. And yes, AC check was originally next on my list. Am I right to expect circa 50V ac?

Yes, Steve. That's about right. All combinations should read about the same. Here's a good reference, starting at post #18:
https://www.st-owners.com/forums/showthread.php?t=84285

Hope this helps. I added a comment to my post (#9) above.

John

 

[stevewp]

Well, that winding can trick one...
On the '94 I'd throughout refurbed, all initial readings & measurements were OK, but the bike went dead like 300ft from the MOT station...
Stator shorted to ground...

NOOOOOOOO!!!!!! You can't say that! Rofl.

In fairness, I have to confess, I haven't ridden the bike til now since early August last year, which was beautiful weather. Not a planned outage, but just the way things have gone. So it's mostly seen decent weather for some time now but been stood for 6 months. Which of course has resulted in quite a number of short-timed starts (for turning over purposes, plus the annual test etc) and then, on the first day out on it (Friday) it bucketed it down with rain for most of my journey to and from work (70 mile round trip). I wonder if all that has just made something thrown its hands up in the air and quit, whether it be wiring itself, the VRR or the alternator.

 

[stevewp]

Yes, Steve. That's about right. All combinations should read about the same. Here's a good reference, starting at post #18:
https://www.st-owners.com/forums/showthread.php?t=84285

Hope this helps. I added a comment to my post (#9) above.

John

Yup, appreciate the suggestion in Post #9

I'll take a scout through the linked post too.

 

[stevewp]

Some good info in that thread, though it seems he didn't cure the problem after all. It is making me wonder if it may even just be the battery. It's certainly VERY likely to be fried following last night's ride home.

As a point of note, for those cleverer than me, towards the end of the ride, I stalled the old girl. Obviously wouldn't restart. Got the wife to jump start me and, whilst just getting ready, I noticed that the voltmeter was jumping around a bit but was certainly showing a more reasonable level of volts. Much to my disappointment, as soon as I pulled away, it was like a bunch of leaches had attached themselves to the battery as the the motor dropped back off the bottom of the scale. Wonder if that provokes any new theories?

 

[Brant]

Some good info in that thread, though it seems he didn't cure the problem after all. It is making me wonder if it may even just be the battery. It's certainly VERY likely to be fried following last night's ride home.

As a point of note, for those cleverer than me, towards the end of the ride, I stalled the old girl. Obviously wouldn't restart. Got the wife to jump start me and, whilst just getting ready, I noticed that the voltmeter was jumping around a bit but was certainly showing a more reasonable level of volts. Much to my disappointment, as soon as I pulled away, it was like a bunch of leaches had attached themselves to the battery as the the motor dropped back off the bottom of the scale. Wonder if that provokes any new theories?

Check batt. voltage with a hand held meter. should be 12.6v or better. Key on, check that battery voltage again.

 

[Slydynbye]

Some good info in that thread, though it seems he didn't cure the problem after all. It is making me wonder if it may even just be the battery. It's certainly VERY likely to be fried following last night's ride home.

As a point of note, for those cleverer than me, towards the end of the ride, I stalled the old girl. Obviously wouldn't restart. Got the wife to jump start me and, whilst just getting ready, I noticed that the voltmeter was jumping around a bit but was certainly showing a more reasonable level of volts. Much to my disappointment, as soon as I pulled away, it was like a bunch of leaches had attached themselves to the battery as the the motor dropped back off the bottom of the scale. Wonder if that provokes any new theories?

Uh oh. Was the wife's car running when you jumped the bike? I would always jump off a NON running car.

 

[stevewp]

Don't worry - it was turned off

 

[stevewp]

Good volts on the yellow wires with the engine running. No shorts to earth on the stators. Remade all connections. No improvement.

 

[John OoSTerhuis]

Next: controlled substitution with a 'known-good' VRR (and maybe a battery too).

Anyone close to Steve that can help out?