Voltage drops as RPM increase

[MadFrog]

This morning on the way to work, I noticed that I was getting pretty low voltage at 5k RPM: ~13.3V. The voltage seems to be fluctuating a fair bit more than it used to. Also, the voltage was back to near-normal levels around 2700RPM: ~14.4V - but still unstable (variations of +/- 0.5V)

What's fried?

It's a 4th gen (1994) with 58k miles on the clock, the previous owner said he changed stator and R/R around the 25K mark, and I changed the battery last year (around 55K miles)

TIA.

[Tightwad]

Check your R/R and Starter Relay connections for any signs of burning/melting. If those are good, i would bet the problem is your R/R....those are only 25 amp units and fail all too often.

[NorthernVFRDave]

I don't think anything is fried, we're only taking about a half a voltage change. I've watched my 07, and the voltage on it swings +/- 1.2volts most days, based on the voltmeter but it all comes down to the meter itself. Digital meters are slow

The question is, is this something new that’s just started to happen or has it been the norm.

[Guest]

What's fried?

Your battery. Yes, even if you replaced it last year.

Replace it before it causes the R/R (or other parts) to go.

Also, make sure you determine WHAT caused it to go and correct the issue. It could have been a defective battery (e.g., internally), but check all your leads and voltages.

Mine did the same (voltage dropped with increase in RPM), and my battery was new a year prior, too.

[Jmmymc750]

I vote r/r...get one from Josh!

[MadFrog]

What's fried?

Your battery. Yes, even if you replaced it last year.

Replace it before it causes the R/R (or other parts) to go.

Also, make sure you determine WHAT caused it to go and correct the issue. It could have been a defective battery (e.g., internally), but check all your leads and voltages.

Mine did the same (voltage dropped with increase in RPM), and my battery was new a year prior, too.

I'll take the battery to the local parts store to have it tested.

I'll also take a look at the connection to the R/R and stator (those are all on the right side of the bike, correct? R/R by the rear brake fluid reservoir and the Stator by the fuel tank?)

The float has been increasing over the past few months, but the voltage drop at higher RPM is pretty new. I've just now noticed it, so it can't have been happening for more than a few days. Also, generally, the voltage has been about a half volt lower this season than I remember last year.

I may also just order a VFRness from tightwad to replace over the winter regardless of what the problem is - cheap insurance it seems.

[MadFrog]

I vote r/r...get one from Josh!

Who's Josh?

[Tightwad]

I vote r/r...get one from Josh!

Who's Josh?

That would be me. Battery is also a distinct possibility, a bad cell could read like that. VFRness is a good option also, but usually isn't a fix unless you have bad connectors. Check the Starter Relay...those often burn up on these models as the charging voltage goes through them.

[Jmmymc750]

I vote r/r...get one from Josh!

Who's Josh?

Josh already answered but he's the genius behind "wiremybike.com"! You can get the VFRness - which is an add on harness that plugs right in to your existing harness with better grounding for the charging system. You can also get the latest, greatest aftermarket r/r. I think he even makes a kit for Yamaha R1 r/r replacemnt. So, pretty much, Josh is "the man" when it comes to electrical stuff.

Cheers

[Guest]

D13.3 doesn't seem too low, although going down isn't a good sign. I don't think you will have any issues unless your battery is just getting too old.

[MadFrog]

D13.3 doesn't seem too low, although going down isn't a good sign. I don't think you will have any issues unless your battery is just getting too old.

It's not so much that 13.3 is so bad, it's that it was 14.x last week at 5k RPM AND the voltage is higher at a lower RPM that worries me.

Thanks for letting me know Josh == TightWad. I'll be troubleshooting this this weekend. What year R1 R/R do we need to get? 04/05/06?

[MadFrog]

got home and ran the simplest tests:

- all 3 connectors (starter relay, R/R, stator) look OK.

- battery at rest (bike OFF) at 12.8v

- battery with bike ON at 11.8v

- tested the 3 stator wires: no connectivity to ground, and about 0.5 - 0.6 ohm between each pair of them

I guess the next step is figuring out how to test the stator with the bike running - do you just disconnect at the R/R and measure there, or is there a procedure to follow?

after that, take the battery to the local Pep Boys this weekend.

[Auspanglish]

Well the battery is looking fatigued with those readings w bike off.... 12.8 is low for me so she's probably gone to the dogs... still... you have to determine what killed the battery... "suicide" (possibly just died in the a$$) or homicide (R/R, stator or bad wiring, starter reay, etc...) and yes, you just disconnect the stator from the R/R and take readings at the connector (stator end)... the bike will be running purely off the battery with the latter receiving no charge at all, so probably a good idea to get a new battery in there beforehand and make sure it's charged up... don't leave it running for half an hour like that... should take you a couple of minutes to get proper readings... 11.5 V (AC) for each 1000 RPM.... oh and if the battery's low on juice, you won't be getting good readings on R/R output as it will be compensating for this... the stator eadings with the bike off you posted are OK

[HispanicSlammer]

Voltage dropping at higher rpm, and voltage fluctuations are classic signs that your rr is bad!

[MadFrog]

Voltage dropping at higher rpm, and voltage fluctuations are classic signs that your rr is bad!

Cool, thanks for all the info. I'll finish the troubleshooting to make sure the stator is ok and get the battery tested to see if it needs changing. Then I guess I'll be ordering a R1 R/R from fleabay and maybe a modified VFRness from Josh.

[Knife]

My understanding is that you should have 12+v when off, 13+v when idling, and 14+v at 5000 rpm. I just replaced my battery, stator, R/R, and patched the wiring (I have a VFRness also), and those are the readings I get now. (And by the way, I get all my electrical stuff from Tightwad at Wire My Bike, e.g., R/R, stator, VFRness, Powerlet stuff, etc.)

[spud786]

when you guys do the stator ground testing USE the highest ohms scale or you can miss a shorted stator . use a big mega ohm scale

[MadFrog]

when you guys do the stator ground testing USE the highest ohms scale or you can miss a shorted stator . use a big mega ohm scale

yup, that's what I did - still showed "OL" (Open Line)

[NorthernVFRDave]

when you guys do the stator ground testing USE the highest ohms scale or you can miss a shorted stator . use a big mega ohm scale

The real way to test this would be to use a megger, which will generate a DC voltage of up to 1000 volts between the stator line and ground. This will truly test the insulation of the stator. A good value is 10,000 ohms per volt, so for the bike at 13volts =130,000+ohms. Anything below that would be signs that the stator insulation is starting to break down. Your at home voltmeters will only put about 9volts in to the line so you'll see OL or open even with the best mutli-meters.

It very well could be the stator starting to break down, but it may also run another 6 months before it does fail.

[Tightwad]

R1 R/R you are looking for is the 2008+ model FH012AA is the number. It should be explained that other R1 R/R s look the same, but could use old Shunt technology and would not function the same (might work just fine as you wouldn't know the difference most likely). You could also retrofit to a newer 1998-99 model R/R that has MOSFET technology. The tough part of the R1 mod is the connectors...the only source I have seen for them is EasterBeaver.com. The VFRness I sell that fits for these years uses them, so there would be a delay in building as I would have to order from Jim. I don't make a VFRness using those connectors for the 98+ models because there is already an aftermarket solution for them (the new R/R I sell is MOSFET)

This link shows the various Shindengen models, only one of which is MOSFET:

http://www.shindengen.com/content.cfm/regulator_recitifers

[spud786]

What's fried?

Your battery. Yes, even if you replaced it last year.

Replace it before it causes the R/R (or other parts) to go.

Also, make sure you determine WHAT caused it to go and correct the issue. It could have been a defective battery (e.g., internally), but check all your leads and voltages.

Mine did the same (voltage dropped with increase in RPM), and my battery was new a year prior, too.

I'll take the battery to the local parts store to have it tested.

I'll also take a look at the connection to the R/R and stator (those are all on the right side of the bike, correct? R/R by the rear brake fluid reservoir and the Stator by the fuel tank?)

The float has been increasing over the past few months, but the voltage drop at higher RPM is pretty new. I've just now noticed it, so it can't have been happening for more than a few days. Also, generally, the voltage has been about a half volt lower this season than I remember last year.

I may also just order a VFRness from tightwad to replace over the winter regardless of what the problem is - cheap insurance it seems.

when my last stator failed, its was running about 13,9 volt on the road, for 2 weeks, I noted the obvious degrade, cause normally its up around 14.7, then it just died, sounds kinda similar.

dont expect more than about 50,000 mile out of a stator, the run very hot and the laquer eventually fries

[Auspanglish]

Voltage dropping at higher rpm, and voltage fluctuations are classic signs that your rr is bad!

Simply put and makes all the sense in the world... if it were the stator, values would probably be below par ALL the time... the regulator does what the stator can't,: vary the voltage... as the stator lineally puts out more, the more you rev... if the more you rev makes the voltage drop... it would point more so to the R/R.

I understand from the manul that 12.3 V is critical.

[MadFrog]

R1 R/R you are looking for is the 2008+ model FH012AA is the number. It should be explained that other R1 R/R s look the same, but could use old Shunt technology and would not function the same (might work just fine as you wouldn't know the difference most likely). You could also retrofit to a newer 1998-99 model R/R that has MOSFET technology. The tough part of the R1 mod is the connectors...the only source I have seen for them is EasterBeaver.com. The VFRness I sell that fits for these years uses them, so there would be a delay in building as I would have to order from Jim. I don't make a VFRness using those connectors for the 98+ models because there is already an aftermarket solution for them (the new R/R I sell is MOSFET)

This link shows the various Shindengen models, only one of which is MOSFET:

http://www.shindengen.com/content.cfm/regulator_recitifers

I tested the stator this evening and it seems fine: 63-65V between the phases around 5k rpm. So, I now assume that it is the regulator, although I will get the battery load tested on saturday.

Now, Josh, you have confused me. You are saying that you carry R/R for 98+ bikes from Rick's and they are MOSFET. Are the Rick's R/R that you sell for previous model years NOT MOSFET? (my bike is a '94) And how long is the delay to get the connectors from Jim if you need to build a '94 harness? If that is too long for me to wait, where can I find a pin map to tell me which R1 R/R pin goes to which VFR pin?

Everywhere I looked in the electrical forum, people seem to be using the 04/05/06 R/R from the R1 - maybe I can find out from a seller if it has the FH012AA model number before buying?

[MadFrog]

R1 R/R you are looking for is the 2008+ model FH012AA is the number. It should be explained that other R1 R/R s look the same, but could use old Shunt technology and would not function the same (might work just fine as you wouldn't know the difference most likely). You could also retrofit to a newer 1998-99 model R/R that has MOSFET technology. The tough part of the R1 mod is the connectors...the only source I have seen for them is EasterBeaver.com. The VFRness I sell that fits for these years uses them, so there would be a delay in building as I would have to order from Jim. I don't make a VFRness using those connectors for the 98+ models because there is already an aftermarket solution for them (the new R/R I sell is MOSFET)

This link shows the various Shindengen models, only one of which is MOSFET:

http://www.shindengen.com/content.cfm/regulator_recitifers

I tested the stator this evening and it seems fine: 63-65V between the phases around 5k rpm. So, I now assume that it is the regulator, although I will get the battery load tested on saturday.

Now, Josh, you have confused me. You are saying that you carry R/R for 98+ bikes from Rick's and they are MOSFET. Are the Rick's R/R that you sell for previous model years NOT MOSFET? (my bike is a '94) And how long is the delay to get the connectors from Jim if you need to build a '94 harness? If that is too long for me to wait, where can I find a pin map to tell me which R1 R/R pin goes to which VFR pin?

Everywhere I looked in the electrical forum, people seem to be using the 04/05/06 R/R from the R1 - maybe I can find out from a seller if it has the FH012AA model number before buying?

Update: it looks like the '04-'06 R1 R/R are part number FH011AA. So, still a MOSFET regulator - they do look like the fins are higher than on the later models. Anybody have pictures of an install on a 4th gen? Did it require the fins to be trimmed?

[Tightwad]

It takes about a week to get the R1 connectors. The 90-97 R/R is not MOSFET. I can build a conversion to use the 98+ MOSFET version easily enough, so the VFRness would be integrated in the conversion.

Here is what the connection would look like for the R1 R/R:

Not that left connector is Stator wires (any order) and right connection is power/ground...power on the left, ground on the right.