How to figure out if problem is R/R or Battery or something else?

I got my 1998 VFR with 10,000 miles a couple of months ago and right from the start it felt just a bit hesitant to start. Once started it was brilliant, very smooth.

Yesterday, I took the battery out and charged it, thinking it might be the problem with the hesitant starts. When I plugged it in to the battery charger, it almost immediately (within 5 minutes) showed the battery as 80% charged. Fully charged in 30 minutes.

So I put the battery in and went for a ride. The bike didn't start any better (maybe just a tiny bit better) with the charged battery but I went for the ride anyway. After a couple of hours, I stopped to take a break and the bike wouldn't start back up.

When I turned the key the lights and everything came on and the engine turned over a bit and didn't start. I tried again after turning the key off for a minute and this time all I got was a "KRRRRR" sound and the lights went dim on the dashboard and headlights so I turned it off and called for a jump start.

An hour later the guy came over with the jump start kit and the bike started right up. While he was there I tested turning the bike off and got the same problem. So, I got it jump started again and drove home about 50 miles. On the way, the headlights became really dim as did the dashboard lights. The bike also was a bit hesitant at certain RPMs (probably 5.5k) and fine at other.

The bike was completely fine when stopped at the lights and idling, including the headlights which came back to full power. Only when bike was on the move the headlights became dim again and the bike seemed to sputter a bit.

Do these symptoms sound like a dead battery or R/R or some other problem?

Try this:

Lifted this done by a m8 of mine:

Firstly, if you suspect the Voltage Regulator/Rectifier (R/R) is at fault, you are not unique. My advice at this point is...........DON'T PANIC.

What is the Voltage Regulator/Rectifier and what does it do?

The R/R is a little gizmo, a bit larger than a cigarette packet, that converts the AC output from the Alternator into a DC input for the battery - hence the Rectifier part of it's name. It also controls the DC input to the battery in a controlled voltage range - hence the regulator part of it's name.

How the Voltage Regulator/Rectifer works.

Inside the R/R there is a six diode full wave rectifier, and the three-phase input from the alternator can be switched to ground through a thyristor. The thyristors are switched by a regulator circuit that measures the DC output voltage. This is called a shunt regulator. The unit is fully integrated and if one aspect fails so will the other.

The R/R relies on being a heatsink to dissipate the heat generated. This works well as long as there is good thermal contact between the diodes and thyristors inside the R/R to the housing, that is why it is a good idea to use heatsink paste between the R/R and frame as this extends the heatsink into the frame.

The Alternator in more depth.

On the VFR, the alternator stator is three-phase. It has 18 poles - 6 per phase. Each pole has about 20 turns of copper wire on it. On each phase of a delta wound system you will have 120 turns, giving 360 turns altogether. Because the stator is mounted inside the engine, even though they're cooled by the engine oil, the heat from the engine could affect the insulation on the copper windings. The insulation for the windings could break down between the windings. If this happens, it can do so under load and when the engine is hot. If you get a few of these shorts in between the phase outputs you will no longer have 120 turns but maybe 60 turns. You will still get 13.5+ volts from the R/R, but since the VFR uses a delta wound stator, those 60 turns will give a much lower AC voltage and much higher AC current. As the diodes in the R/R don't like high currents they get hotter than normal, which although it leads to them becoming more efficient (i.e. having a smaller voltage drop across them) they produce more heat which accelerates their failure.

History

The failure rate for this component on the '98 FiW and '99 FiX models is somewhere in the region of 65 to 70%. Generally, the failure of the R/R on the VFR gives an under-volt condition, i.e. it doesn't charge the battery. Mind you, there has been the odd, but much rarer, failure to the over-volt condition which boils the battery and can blow bulbs.

The failures are mainly down to the inability of the R/R to shed heat, which then fries the electronics in them. If you touch one after a ride, you'll find it quite hot to the touch anyway.

It is possible to fit a computer cooling fan (as below) to try and prevent the problem, but I think it merely delays the inevitable. Mind you, it didn't stop me fitting one just in case.

An upgraded R/R is available for the '98 FiW and '99 FiX models with improved cooling capacity and has, so far, proved much more reliable than the original. The upgraded replacement is a direct replacement.

Luckily, Honda realised there was a problem and replaced the R/R on the '00 FiY and later models for one that's a whole lot more reliable with a failure rate of about 15%. The later one comes with an additional voltage sensing wire, which means it's not a direct replacement for the earlier model, but it's not insurmountable to fit one if you want.

Symptoms.

The usual symptoms of the R/R going AWOL in the under-volt condition are:-

1. The clock resets to 1:00 AM and the tripmeter resets to 0 miles when you start the engine.

2. The engine fails to start, this can happen even if was running a few minutes previously. Often when you've stopped for fuel.

3. The rev counter and speedo needle start to do "strange" things.

4. The bike may start to stutter and cut out.

The symptoms of the R/R failing to the over-volt condition can include:-

1. Blowing bulbs.

2. Boiled battery.

Things to check.

Starting with the simple things:-

1. Check the battery connections are clean and tight. It's not been unknown for the connections to come loose.

2. Check the electrical connections to the R/R are clean. Sometimes they get corrosion in them, which ups the resistance and causes it to overheat. The overheating, in extreme cases, can melt the plastic.

If those haven't sorted things out, you really need to buy a multimeter. These cost less than £10 and will prove a bonus from here on in. If you're not confident in using one - read the instructions and practise getting DC voltage readings from it. Start practising with a little dry cell (1.5 volts) battery if needs be - we all have to start somewhere.

Warning

:- Never, ever connect the multimeter to both battery terminals unless it's selected to the DC volts range. The resistance across the meter when selected to read volts is very, very high so it can measure the difference across the terminals without damage. The meter resistance when selected to amps is very, very low and would effectively short out the battery, possibly melting the leads and blowing the meter up.

Now we're moving into the nitty-gritty.

How old is the battery?

Anything over 3 or 4 years old and it may be past it's best. As they deteriorate, batteries can lose their effective capacity, i.e. they behave as a smaller battery, so, it may be worth doing a selection of load tests on it.

Battery load tests.

As with many electrical problems, make sure the battery is fully charged. If the charging system is playing up, you've only got a finite amount of power available from it.

a. Off-load test - connect a voltmeter (selected to volts DC) to the battery and off load a fully charged battery should sit at about 12.7 or more volts. Even a failing battery can pass this test at times.

b. Low-load test - a low load test is done with the engine stationary and just turning the bikes lights on and taking a voltage reading at the battery. The battery should have at least 11.5 volts with the lights on.

c. High-load test - this is done when cranking the engine over on the starter motor. You should have more than 10.5 volts while the starting motor is cranking the engine.

If the voltages are appreciably lower than those values, the battery is probably on it's way out.

Replacement Batteries.

If you need to replace the battery, then get a recognised and quality make. For example, the Yuasa YTX12-BS is available from Halfords at around £50. Before you fit it to the bike, ensure it's been fully charged. If you want to fit a higher capacity battery, the Yuasa YTZ-14S (from an ST1300 Pan European) fits - it's the same length and width, but a tad shallower so needs some packing pices to lift it to get the battery leads to connect.

What model of R/R is fitted to your bike?

If you lift the seat and have a look just outboard of the LH subframe rail, just behind the cutout in the rear fairing you'll see a grey box a bit larger than a cigarette pack. If it's made by Shendingen (who make them for Honda) you'll see a number on the top of it starting with SH. If it's SH579A-11, then you've one of the original and gloriously unreliable R/Rs fitted. If so, then there's a good chance it's put up the white flag.

If the number on it is SH689DA, then you've got the upgraded item. As mentioned earlier, it is much more reliable than the original, but there is still the possibility of a random failure. Anything else is a non-standard or pattern-part R/R.

As a comparison, in this photograph the original SH579A-11 is on the left and the upgraded SH689DA is on the right.

The '00 FiY and '01 Fi1 models had R/Rs with SH579C-12 on them which are much more reliable than the original SH579A-11 model.

No matter which model is fitted, it'd be worth doing a charging system output voltage check.

Output voltage test.

As alluded to already, the R/R fails when hot, but it can seem to recover when it's cooled down again. The ideal time to do this test immediately after a ride round, if possible without stopping the engine and remove the seat using the spare key.

1. With the voltmeter (set to the volts DC range) connected to the battery, at 4000 - 5000 rpm with the lights off you should have anywhere between 13.5 and 15.5 volts.

2. Turning the lights on could cause the voltage to drop by up to 0.5 volts.

Anything seriously outside those ranges could indicate the R/R is giving up the ghost.

Although Haynes specify the charging voltage should be 14.2 volts for the FiW/FiX models. It's nice if you can get it, but don't worry if you can't. For example, the upgraded SH689DA model regulates at 13.8 volts - chase the 14.2 volts and you'll be throwing a lot of serviceable R/Rs away.

Another oddment, is some people say the lights should get brighter when you rev the engine. That isn't necessarily the case. The SH689DA model can provide more voltage at idle (or slightly above it depending on what idle speed you've got set) than at higher revs, for example, the one on my VFR provides 14.2 volts at idle, but 13.7 volts at 5000 rpm.

Please be aware that multimeters can have slight errors between them. What one is reading could be very slightly different on another.

Replacement Voltage Regulator/Rectifiers.

Use the upgraded OEM one. Electrex make one, but it's reliablity record isn't anything to shout about.

To get an upgraded OEM one at a good price, try David Silver Spares whose prices compare very, very favourably with those from a Honda dealer for exactly the same item.

They list two different ones for the '98 FiW and '99 FiX. The cheaper (pattern) one is identical to the OE one, just supplied in a poly-bag. Also included is a set of longer bolts (the upgraded R/R is thicker than the original as can be seen in this link) and an additional aluminium heatsink.

Reuse the original domed nuts as these stop the bolt ends rubbing away at the nearby wiring loom. It can also pay dividends to put some heat transfer paste (available from outlets such as Maplins) between the R/R and the heatsink and between the heatsink and the rear subframe. That'll help transfer extra heat from the R/R into the subframe.

An alternative that I use, and recommend, is fitting an R/R from a '04 - '06 Yamaha YZF-R1 (Shindengen Part No. FH011A) - as shown below. More details of that are contained in this thread:- deleted. They can often be found for sale on eBay, which is were I sourced mine from for a very reasonable sum.

I'd also tend to advise, if the battery is over 3 years old or of unknown history, replacing that at the same time as the R/R. A failing battery can over-work the R/R hastening it's failure.

The charging system voltage is OK, the battery load test voltages are good, the alternator resistance values are fine, but the battery still flattens quite quickly.

Now we're looking at the battery leakage rate. This is the current (Amps) the bike draws even though everything is turned off.

Ideally the leakage should be less than 1.2mA, but with an alarm fitted and armed it might marginally higher than that. It might be worth consulting the alarm instructions and seeing what current it draws.

You'll need to set your multimeter to the highest DC Amps range. this is to stop the meter overloading when it's connected. On some models of multimeter you'll need to change which connection the red lead goes to.

When set to read amps, under no circumstances connect the multimeter between the battery terminals, otherwise you could short out the battery, melt the leads and wreck the meter.

1. Disconnect the battery negative (earth) lead.

2. Set to multimeter to the highest DC Amps range.

3. Connect the multimeter between the battery negative terminal and the disconnected negative (earth) lead.

4. Going down one DC Amps range at a time, reduce the range until the reading is sensible. Always start high to protect the meter from overloading.

5. The ideal leak rate should be below 1.2mA, but as mentioned above it may be very slightly higher because of any alarms/immobilisers, but not substantially so.

If the leakage is substantially higher than 1.2mA, try pulling and refitting fuses one at a time and seeing which fuse make the biggest difference to the leakage value when removed. This'll give you a clue as to which circuits are drawing too much current.

If you've replaced the Voltage Regulator/Rectifier and Battery and the charging system voltage is still too low.

If this is the case, then there's a good chance the alternator is failing.

Because the alternator is mounted inside the engine the heat from the engine could affect the insulation on the alternator stator windings. The insulation may even break down between the windings. This typically happens under load and when the engine is hot. You will still get a good output voltage from the R/R, but as the VFR uses a delta wound stator, the alternator will give a much lower AC voltage and much higher AC current.

To check the insulation of the alternator stator coils you'll need to do the following:-

1. Disconnect the R/R connection to the alternator - the one with the 3 yellow wires.

2. Select the resistance (Ohms or Ω) range on your multimeter and touch the two probe ends together. The readout on the multimeter will give you the effective zero reading - so if there is a value shown and your multimeter cannot be zeroed - as many cheaper ones can't be, you'll have to deduct this number from any further measurement.

3. On the three yellow wires coming from the alternator (not the ones from the R/R by accident) measure the resistance between each of the wires in turn, i.e. have one probe on the connection to one yellow wire, then touch the other probe to the connections for the other two yellow wires. So if one probe is one wire 1, place the other probe on wire 2 then 3. Then move the probe from wire 1 and put it on wire 2, then place the other probe on wire 3. That way all combinations are covered.

4. The resistance readings in step 3 should be anywhere between 0.1 Ohm and 1 Ohm - remember to deduct the resistance reading you got in step 2 from the values you saw in step 3.

5. Now test the resistance between each of the yellow wires and earth. There should be no continuity, i.e. infinitely high resistance, between any of the yellow wires and earth.

If the values in step 4 or step 5 are outside the tolerances, then there's a pretty good chance the alternator stator coils are knackered.

I will warn you though, having received further information from Brains, the above procedure may not conclusively prove the alternator stator serviceable or unserviceable. As Brains reminded me, a multimeter doing resistance checks only uses a few volts, whereas the alternator at high speed may well be inducing in excess of 200 volts at high engine speeds - a much bigger test of the insulation of the windings. Therefore there is the real possibility that a multimeter will say everything is OK, but in use it may well not be.

Also, a visual inspection of the alternator windings may reveal some discolouration/burning that may be indicative of them starting to break down. However, that does require the alternator to be removed.

Real time charging system monitoring.

If you're concerned about the state of your charging system and want to monitor it without the faff of getting a multimeter out every time, there's nothing to stop you fitting a small voltmeter. I have a Lascar EMV1200 fitted to the Big Red Bus - my VFR.

Hope that's of some use to someone.

Thank you so much, that is the information I need.

The usual symptoms of R/R failure are there (trip meter reset to 0, clock reset to 01:00) and the rest. I'll make sure to go through the whole thing however.

Hopefully it will be of some assistance.

Written by a m8 of mine for another site.

Trip and clock reset are directly battery related , course charging can effect battery too, but flakey batteries can create all sorts of issues, as the battery might have plenty of output at times, yet too little cca to turn the motor over. Always start with a known good battery, as nothing else maters if the battery is flakey, a vfr will not run right without a Good battery

I found that the battery was toast so I replaced that. The R/R is the SH689DA: the upgraded one.

Did a voltage test with the bike idling and the voltage is fine at 13.9 V. Will do another test after a ride.

spud786Always start with a known good battery, as nothing else maters if the battery is flakey, a vfr will not run right without a Good battery

Yup. :smile:

Excellent summary, Skids. Thanks.

Ciao,

Wow! Phenomenal assistance.

I am wondering if the r/r might be the problem on my 2000 with blowing out the High Beam bulbs? Are the numbers on the r/r as described above the same on 2000 model year VFRs?

I would love to know -- I've lost beams as the worst times, and they are a bit of a PIA to replace. Thanks.

jaydj

Wow! Phenomenal assistance.

I am wondering if the r/r might be the problem on my 2000 with blowing out the High Beam bulbs? Are the numbers on the r/r as described above the same on 2000 model year VFRs?

I would love to know -- I've lost beams as the worst times, and they are a bit of a PIA to replace. Thanks.

AFAIK, the upgraded r/r will fit any Fi (5th Gen).

Hi there,

Just wanna find out smth. I am currently using a r1 R/R and my charging at 4000-5000 rpm is 13.7V as I will be going for a trip, my mech is concern with the low charging voltage. So he actually do a bypass by doing a connection from wire from the R/R to the battery directly to bring the charging voltage to 14.2V. My concern now is that would it cause any harm to the R/R or the alternator?

I hope someone here with the technical know how can advice me so that I can have the peace of mind when going for my long road trip.

For future reference, I have used and loved the following flow chart to figure out my charging issues. Easy to use and very clear.

http://www.electrosport.com/technical-resources/library/diagnosis/pdf/fault-finding-diagram.pdf

Not a issue of fault finding with the R/R but rather since my mech use 2 wire and drew current from 2 wire to and from the R/R, I was thinking if that is the right way to bring the charging voltage up. Will this cause harm to the R/R. Like causing it to overheat and burnt out of some sort.

I've had good luck with my Compufire RR so far (series regulation, so easier on the alternator) Wired directly to the battery terminals.

Jtzw1988

Hi there,

Just wanna find out smth. I am currently using a r1 R/R and my charging at 4000-5000 rpm is 13.7V as I will be going for a trip, my mech is concern with the low charging voltage. So he actually do a bypass by doing a connection from wire from the R/R to the battery directly to bring the charging voltage to 14.2V. My concern now is that would it cause any harm to the R/R or the alternator?

I hope someone here with the technical know how can advice me so that I can have the peace of mind when going for my long road trip.

im kinda wondering how he would be able to do that (13.7-14.2) that only thing that i can think of is cleaning up the connections and maybe a 2nd positive to the battery. in the other hand there is really no way to bypass the system. it can only go one way: alternator (charges with ac current) -> R/R (converts ac-> dc) -> battery. from what i can get from your post is he is going to cut the positive and negative wires from the R/R and wire in a new positive and negative to bypass the wiring harness, so in the end he isnt going to bypass it he is just going to rewiring the connections (from what im getting) but ask what he/she (your mechanic) is actually going to do

Now that u mention, I think it's what u thought it to be. I din really ask much cos I am technically not savvy. But based o what u just said, what is he actually doing?

Larger diameter wire= less voltage loss .(within reason)

Lots of good information here. I recently installed a VFRness and r/r on my 4th gen. I bought a replacement stator too but haven't installed it yet. Will do the stator checks.

Now as part of the repairs I installed a voltmeter. So let's say I am riding along miles from home and notice an undercharge condition or overcharge condition. What should I do? It seems practical enough to carry a spare r/r but not an extra battery or stator.

If it is undercharging should I try to reduce the electrical load? Unplug a headlight bulb, or both if it is daylight?

What if it is overcharging? Should I disconnect the r/r to prevent it from getting fried? My battery won't be charging but I could periodically re-connect the r/r to get a little recharge.

Any other helpful tips would be appreciated.

Does anyone know what the stator VAC readings should be when the bike is warm/hot (>190 deg F) and could advise if that is an indication of the cause of the problem below?

Battery with bike off, fully charged, 13.5V

Battery voltage when bike is started, ~14.5V

Battery voltage @ idle once the bike is warm, ~13.5V

Stator output cold, pin to pin is ~23VAC @ idle, going past 50 VAC at 4-5k rpms (I am holding the leads and doing the rev'ing, so it's hard to get a perfect reading)

Stator is open to ground on each pin (I used the ground point on the other side of the bike. If there is a better point to use, please advise!), and is 0.6, 0.6, 0.8 ohms pin to pin.

All the above seems OK, right?

Here is the problem that I am having... If I start riding, the voltmeter is steady at 13.5 to 13.7 at idle, and 14.5-14.6V at 4-5 k rpms as I ride. There are no issues with how the bike is running, etc. After about 10 miles, sometimes shorter, the voltage suddenly drops to battery voltage. Very sudden. From there, the battery voltage starts at 12.7V and slowly drops at the battery discharges. A couple of times, the bike has popped back to correct readings for a few mins/miles, but then back to battery voltage and repeat symptoms above. Generally speaking, after I get home the bike requires charging to be able to start again.

As I looked over the connections withing the charging system, I did not notice anything burned up, etc. One thing that I did this morning was to let the bike get hot, and test the stator output at 195 def F, and I got 13.3 VAC from pin to pin consistently, and it got over 40VAC when rev'ed to around 4-5k rpms (again, not a perfect reading.) Is that normal to have lower output then? If so, does that indicate the need for a stator replacement?

Also, does anyone have a diagram of how to test the specific VFR R/R for diode health or correct voltage across what pins, etc. along with what readings to expect?

Is there anything that I should be checking out that I haven't noted above? I hate only being able to ride a few miles at a time! Thanks in advance!

Sam

Is there some reason why you are suspecting the stator? It's usually the reg/rec that goes bad, and high-temperature failure is a well-documented mode...

Ciao,

auggius

Lots of good information here. I recently installed a VFRness and r/r on my 4th gen. I bought a replacement stator too but haven't installed it yet. Will do the stator checks. Now as part of the repairs I installed a voltmeter. So let's say I am riding along miles from home and notice an undercharge condition or overcharge condition. What should I do? It seems practical enough to carry a spare r/r but not an extra battery or stator. If it is undercharging should I try to reduce the electrical load? Unplug a headlight bulb, or both if it is daylight? What if it is overcharging? Should I disconnect the r/r to prevent it from getting fried? My battery won't be charging but I could periodically re-connect the r/r to get a little recharge. Any other helpful tips would be appreciated.

THe 5th gens dont have the output as the 6th gens, including aftermarket wiring which can effect the output. But if you reading below 13.5 volt, its not enough charge.

JZH

Is there some reason why you are suspecting the stator? It's usually the reg/rec that goes bad, and high-temperature failure is a well-documented mode...

Ciao,

Hi JZH, I agree that it is probably the RR, based on the info that I have read about the hot RR failures. I just wanted to get a sanity check because there are the two things that took me by surprise 1) the suddenness of the failure - literally in the blink of an eye it goes from perfect readings ~14.5V at 5k rpm to battery voltage, and 2) The lower-than-expected output from the stator when the bike is nice and warm (~13VAC).

I just want (as anyone would, really) to first replace the part that has the highest likelihood of being the one that will help me, and usually coming here first gets me the best info out there...

I think that I will order the RR today and see what happens and let y'all know!

Thanks again!

Sam