VFR800fi electrical - battery not charging - long post

[skulkerboyo]

Before I begin I have a new battery on order in case and have followed all the usual flow chart ways of diagnosing stuff but am unable to get a clue on the issue yet.

I posted on VFR world as well but less people over there and they all gave advice for a standard RR and not a MOSFET.

So here goes
Any questions I've highlighted in bold
Non standard reg/rec MOSFET type



Noticed HUD lights seemed dim and she had been cutting out from cold for a few days but thought not much of it as the weather as changed for the colder.



Took her out - stopped at post office - wouldn't turn over - no solenoid - clock reset - bugger. Got a bump and road her to the boat yard and stick the battery on charge - charger claimed battery was 50%



She almost survived the ride home - the tacho started hitting zero despite being running and she cut out just as I got home as luck would have it.



Stuck battery on charge overnight then left it for a day to settle and see what she read.

Here's a breakdown by component



Battery

Was reading 12.8 after an overnight trickle which isn't so bad in my books after being discharged twice. 12.5 with key in though and 12v with lights on - so an expected drop but not the brightest of batteries it seems. Bike turned over and started but I left it at that cos I had other stuff to do.
Next day . . . .
Switched her on with lights on and let her sit for a few mins before firing up to see if battery was uttterly knacked. Voltage dropped to the 11s but she started. That's 11 with lights on - not while cranking.

With no lights at 3000rpm voltage was 13.4 - with lights on it dropped to 12.3

With no lights at 5000rpm voltage was 12-13 then 11 then 12.3 then basically couldnt makes it's mind up but never under 11 - with lights I got 10/11/12/10 - again all over the place.

Woth lights she seems to charge at idle speeds but above 3000 it all goes wonky.



Bloody weird but apparently a MOSFET RR will do odd things with charging. Does anyone know what readings I should get at various revs with a MOSFET on a VFR?

Reg Rec

Checked reg rec connectors. All looked ok with no signs of overheating or corrosion - cleaned em up anyway.

Now for some reason I tested the voltages from the the reg rec on the yellow wires by testing between the wires - I got readings of 11.6v - 25v and 25v approx -

Then I tested them to ground the 11.6 was the only one that seems to ground when I tested it against earth for continuity.

Are all three supposed to have continuity to ground? Only one did.



The other wires coming from the reg/rec - two red and two green - no idea what to test there.

Stator

Resistance between yellow wires was approx 0.3 to 0.5 ohms so all good.

There was no draw/continuity from the wires to ground so all seems good there then.

Stator at idle is putting out approx 16/17 on all three wires testing between the three

At 5k it puts out 50ish

Now that all seems good to me.


With the stator connected to the RR I get 7s and 8s at idle- how's that? Is that fine?



Now with the bike idling and the stator block connector disconnected I get 10 and 9 and 9 to a ground point - am I supposed to get a voltage from a stator to ground? is this confirmation of a leak?



All the resistances are fine and there is infinite resistance to ground .. . . bloody confused.






Have checked fuses and connections and solenoid etc.

Heard tale of problems with grounding but how do I test for this?




I'm optimistically inclined towards battery but not goot at bike electrics.

Are then any more conclusive tests I can do. I know everyone will shout replace the reg rec but it's a recent looking unit and an upgrade and a MOSFET - How do you test those then?.


I had a look for any dodgy grounds but not sure where to look - only interesting thing is my horn switch has had it - horn works when tested alone but the wires get nada so will look at the switchgear later.



I can't think of anything else to test - I've followed all the guides and have a sheet of all recorded voltages etc.





Conclusion so far

I accept that this could simply be a knackered battery that canb;t keep up with the load when lights on so is making it seem like a dodgy RR

I have no idea how to diagnose a MOSFET so hmmm

Stator tests are all fine but I need to know if I'm supposed to get the reading I got when testing f4rom yellow wire to ground - is there supposed to be a voltage there? I'd have assumed not.


I've been pretty thorough here and waiting on the new battery for now but if anyone can answer the questions I have or offer any hints then great. I love the guys over at VFR discussion but despite my detail I seem to have got a load of generic responses about testing the charging system despite having posted about 500 words on all the tests I did on the charging system.

Also the mosfet confuses the issue somewhat for me.

HELP!!
____________________
Zooooooom
Suzuki GP100, NSR250, RGV250, CB400, CB250, CB400, FZX750, FZR750, Honda Bros, Kymco zing 150 (was living in Asia for that one), NTV650, Bandit 600, ZZR600e, Transalp Xl600V.

[RhynoCZ]

The battery: It's fine, there should be 14+V even when the battery is dead, when the charging is working properly.

Stator: 3 yellow wires test is done with the multimeter set at AC, should read around 40V, depends on the bike, definitely not less than 20V when the engine is running, between each combination of those 3 yellow wires. There is a possibility, that one of the coils is dead, which would give you reduced Voltage at one combination, equaling in less power going to the Rectifier that transforms the AC to DC.

Dead Rectifier = No charging at all.
Dead Regulator = Overcharging.
Both, the Rec and Reg are one unit, the only test here is to swap it for a working one and then measure the voltage at running negine at the battery.

For a Reg/Rec test, you may use any Reg/Rec, you just want to give it a short test. I used a 919RR Reg/Rec in a Honda CB-1, just for a brief moment to check mine was alright. I got the same number readout as I should.

I don't question your abilities, but make sure you have the multimeter set right, when you do each one of those tests.
____________________
'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[skulkerboyo]

Hey
Was definitely on AC for those tests.

I'll retest everything again with the new battery though just to be sure I wasn't having a moment.

I'm still mostly concerned about should I get a voltage reading when testing from stator to ground with rr disconnected? If yes then ok

If no then there's a problem. Anyone know this?

That with the only one of the 3 RR wires registering a voltage to ground concerns me - If I can answer those then I may know whether or not to start pulling the loom looking for shorts.
____________________
Zooooooom
Suzuki GP100, NSR250, RGV250, CB400, CB250, CB400, FZX750, FZR750, Honda Bros, Kymco zing 150 (was living in Asia for that one), NTV650, Bandit 600, ZZR600e, Transalp Xl600V.

[ADSrox0r]

Buy a gasket and pull the stator, takes 10 minutes. You'll only lose a cupful of oil.

My money is on a fried coil.
____________________
Current bikes: '08 VFR 800 VTEC(yo) , '07 ZZR1400 Winter hack: '95 Aprilia 650 Pegaso Currently lusting after: RC30

[skulkerboyo]

Hi
Something I'm happy to do but is this advice based on the readings I gave or a "feeling"?

If it's based on the readings I gave then what should be the optimal output from the ac voltage tests for a 2000 VFR - Haynes is no help here.
____________________
Zooooooom
Suzuki GP100, NSR250, RGV250, CB400, CB250, CB400, FZX750, FZR750, Honda Bros, Kymco zing 150 (was living in Asia for that one), NTV650, Bandit 600, ZZR600e, Transalp Xl600V.

[RhynoCZ]

This does sound like a burned stator. The job is easy and if you'll be careful enough, you won't even need a new gasket, but it is advisable to use a new paper gasket.

As I remember, when the engine is OFF, you should read less than 1 Ohm between each combination of the 3 yellow wires going out of stator. The numbers will be like 0.8, 0.7, 0.8. But, as your stator is still in the engine and you can start the engine, then I would take the AC Voltage test at running engine as a prove of my theory, and that is a burned stator (or one of the coils).

You can find the correct AC Voltages, DC Voltages and Ohms and Amps of your electrical system in your service manual.

Before that, I would ask a mate to let me borrow his REG/REC and test it, just in case. If this was a short circuit somewhere, the drain would be present even when the engine is OFF.

The last bit of wisdom, stators are cheap and universal (not really a bike specific part) and the burn damage of a stator does not necessarily have to be easy to spot, visually (look at dark discoloration). When I did mine, I didn't even have to drain the oil and everything was done in less than 1 hour.

EDIT: You do not need a new battery, buy a new stator instead.
____________________
'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[skulkerboyo]

Cheers for the input guys. I mention earlier that when I switch the main lights on it all goes wonky on the voltage side of things.

Should I be testing for an unwanted ground before consigning my stator to the scrapheap??

And I'm still no clearer on whether there should be a reading between between the stator wires and ground when the bike is running.

Ordering a gasket atm - might as well inspect it while I've got her naked .. . .
____________________
Zooooooom
Suzuki GP100, NSR250, RGV250, CB400, CB250, CB400, FZX750, FZR750, Honda Bros, Kymco zing 150 (was living in Asia for that one), NTV650, Bandit 600, ZZR600e, Transalp Xl600V.

[RhynoCZ]

I doubt the lights are the problem. If the charging system is not working properly, then anything that draws power will be a problem. You have 2x55w headlight + several bulbs in the tail light + the bulbs in the clocks.

Mind you the starter motor and lights are the only things that draw a significant amount of power from the battery. The iginition and fuel inejection system do not require much. On a carbed motorcycle, you can do upto 400 miles with no charging, with the lights off.
____________________
'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[stinkwheel]

12.8V across the battery following a trickle charge seems pretty shite.

See if you can find a garage/battery factors with a load/drop tester. (tests its ability to deliver high current from fully charged).
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[ADSrox0r]

You can pick up a drop tester on eBay for less than 20 quid. Bit shitty but they do the job well enough.

https://www.ebay.co.uk/itm/6V-12V-100Amp-Car-Van-Auto-Battery-Load-Drop-And-Charging-System-Tester-452107-/291534070121?hash=item43e0c8e169:g:8qwAAOSwqbZXFKk4
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Current bikes: '08 VFR 800 VTEC(yo) , '07 ZZR1400 Winter hack: '95 Aprilia 650 Pegaso Currently lusting after: RC30

[Robby]

I fitted a MOSFET to my old VFR750. The voltage stayed rock solid, from memory on 13.4V, no matter the revs.

[jaffa90]

[davebike]

VFR800 has a really good charging system when working well but common mod / fix is to wire the output from rec/reg directly to the battery with really good wire at least 60amp
I personally also remove the connector from the stator and wire directly to rec/reg using only warped and soldered joints

I would be suspicious in you case of a poor connection somewhere or a partly burnt stator

Be aware several pattern stators I seen are not a wide or as powerful as original
____________________
Dave
NC750Xdct + others at work !
davebike1@gmail.com

[ADSrox0r]

I fitted a VFRNess (chap makes and sells them in Texas for not too much dollah) for that very reason. Honda in their infinite wisdom routed the neg back through the ignition etc so that had to get sorted. Beefing up the main fuse and wiring is a good preventative measure too since it was somewhat under-specced for the job and melts all too easily.
____________________
Current bikes: '08 VFR 800 VTEC(yo) , '07 ZZR1400 Winter hack: '95 Aprilia 650 Pegaso Currently lusting after: RC30

[skulkerboyo]

no lights
Idle = 12.7 assume 0.1 lost to voltmeter
3000 rpm = 12.8
5000 rpm = 12.9
But they do climb slowly then drop back depending on throttle
With day lights
Idle = 12.4
3000 rpm = 12.8
5000 rpm = 12.9
Full beams
Idle = 12.1
3000 rpm = 12.4
5000 rpm = 12.4
Stator with engine at 100+ celcius all resistances checked out normal
Voltages across three connectors disconnected were
Idle
16 across all approx.
At 5000rpm all 60V
Connected to RR the stator voltages were
8.6 11 and 8.6
Am yet to test the voltages from RR to battery but that’s pretty much every battery and stator test covered.
Is there any value in putting a cheap RR in there for testing? What’s compatible?
Battery settles to 12.8 after all the faffing was done and did climb and charge mostly happily on day lights so I can sort of use her for now but don’t trust her.
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Zooooooom
Suzuki GP100, NSR250, RGV250, CB400, CB250, CB400, FZX750, FZR750, Honda Bros, Kymco zing 150 (was living in Asia for that one), NTV650, Bandit 600, ZZR600e, Transalp Xl600V.

[RhynoCZ]

Reading the values, the rectifier (REG/REC unit) is dead. The rectifier is a diode, when it burns, no power gets past it, so whatever you read at the battery, is just the plain battery, minus the draw of the iginition and other systems. You can find the specific values in your service manual, but in general, at idle you should read more than 13v (close to 14v) and at very high revs it should be around 14.5v (definitely not higher than 15v).

60v at running engine at the yellow wires tells me, the stator (alternator unit) is working perfectly. Once again, the service manual will tell you the specific values, but in general, your stator is working perfectly.

EDIT: Do not think that battery has got to do anything with the charging system. If you can start the engine with the battery, then it's more than just fine. Think of it as the +/- wires that you connect to the battery terminals are a battery charger, that you would normally plug to the wall socket. Even when you charger a dead battery, it would still read 14.5v or so at the terminals while it's plugged to a charger.

Reg/Rec what fits? - Any Honda Reg/Rec, just for the sake of the test, should work just fine.

03 RECTIFIER,REGULATOR 31600-MCW-D61
https://partsdepot.cz/picdily/173149.jpg
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'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[skulkerboyo]

I'm hoping as much.

Everyone keeps bleating about the stator but its passed all tests

Because the rr is a mosfet its gonna put out weird values but I'd expect better than I'm getting.

An rr is cheaper and easier than a stator as well.

Out of Interest anyone know what readings a mosfet would give.
____________________
Zooooooom
Suzuki GP100, NSR250, RGV250, CB400, CB250, CB400, FZX750, FZR750, Honda Bros, Kymco zing 150 (was living in Asia for that one), NTV650, Bandit 600, ZZR600e, Transalp Xl600V.

[jaffa90]

I agree, As RhynoCZ states.

[RhynoCZ]

Read the service manual (google, for free) for the specific values, which are not important at the moment, as we know for sure the Rec/Reg is dead. Change the Rec/Reg, easy job, not expensive.

EDIT: When I say the battery is not important, some charging systems do require the initial power input from the battery, so they start to produce electricity, but that's the old type of charging system. Not sure if dynamo or something else, it was used on Jawa and CZ motorcycles that ran a battery. The battery less ignition systems obviously did not require this.

There you go: https://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC0.H0.X31600-MCW-D61.TRS0&_nkw=31600-MCW-D61&_sacat=0

Or use your local motorcycle parts shop. I very rarely use ebay to buy brand new parts for cars/motorcycles.
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'87 Honda XBR 500, '96 Kawasaki ZX7R P1, '90 Honda CB-1, '88 Kawasaki GPz550, MZ 150 ETZ
'95 Mercedes-Benz w202 C200 CGI, '98 Mercedes-Benz w210 E200 Kompressor

[skulkerboyo]

I'm off to Italy for a week so will only get time to properly install a voltmeter and heated grips while the front fairing is off.

I intend to wire the RR straight to the battery though when it gets here.

What guage wire should I use for this? I see lots of inline fuse stuff on ebay for 30amp at 12v but is it hardcore enough??
____________________
Zooooooom
Suzuki GP100, NSR250, RGV250, CB400, CB250, CB400, FZX750, FZR750, Honda Bros, Kymco zing 150 (was living in Asia for that one), NTV650, Bandit 600, ZZR600e, Transalp Xl600V.

[ADSrox0r]

8 gauge.
____________________
Current bikes: '08 VFR 800 VTEC(yo) , '07 ZZR1400 Winter hack: '95 Aprilia 650 Pegaso Currently lusting after: RC30

[Kawasaki Jimbo]

[skulkerboyo]

Replaced RR and wired the pos and neg straight to batttery (in line fuse of course) - voltage is solid now at 14.2 to 14.5.

Cheers for all the input and analysis of the issue. When I get time I will do some resoldering of parts. I dropped a reg/rec in that fitted on the stator side but not the pos neg side so will take time to solder the yellow wires but for now I have wheels.

Next post will about winterizing her.
____________________
Zooooooom
Suzuki GP100, NSR250, RGV250, CB400, CB250, CB400, FZX750, FZR750, Honda Bros, Kymco zing 150 (was living in Asia for that one), NTV650, Bandit 600, ZZR600e, Transalp Xl600V.