Stator Issues

Hello everyone, I’m here today with a couple questions/thoughts on my stator. To start I have a 2002 VFR800 with about 20k miles. I bought it about 6 months ago and about every 2 months (that I am able to ride) the bike has trouble starting and eventually doesn’t start. So I replaced the regulator And battery, same issue. Did static voltage test on stator and was very low (10-12v). Seems like the test failed.

SO, I now just took out my stator and this is what it looks like. I’m wondering if this is what a bad stator looks like and if any of you all experienced this as well. 

Also, does anyone have tips on getting the wire to the stator out (should I detach the gas tank)? Thanks for any responses!

4 hours ago, max13456

Hello everyone, I’m here today with a couple questions/thoughts on my stator. To start I have a 2002 VFR800 with about 20k miles. I bought it about 6 months ago and about every 2 months (that I am able to ride) the bike has trouble starting and eventually doesn’t start. So I replaced the regulator And battery, same issue. Did static voltage test on stator and was very low (10-12v). Seems like the test failed.

SO, I now just took out my stator and this is what it looks like. I’m wondering if this is what a bad stator looks like and if any of you all experienced this as well. 

Also, does anyone have tips on getting the wire to the stator out (should I detach the gas tank)? Thanks for any responses!

Actually your stator looks reasonably good! (See picture of a bad one attached, they can even be far worse) The coils and varnish don't look too overheated or badly burnt on yours.

"Did static voltage test on stator and was very low (10-12v). Seems like the test failed." !

Did you measure this Voltage at the 3 yellow wire connector unplugged from the R/R? With the engine running and measuring between any pair of the 3 yellow wires you should read greater than 50v AC. (From memory). Did you have your meter set to AC Voltage?

Stators usually fail by shorting to frame. You need to measure the Yellow stator wires for resistance to frame. You should NOT read low ohms to ground. Any low reading will mean your stator has shorted.

You should read a virtual short when measuring between the Yellow wires (coil resistance). Wire to wire.

So the important thing is - How does is measure Ohmically for shorts to ground and coil continuity?

Tie a strong cord to the plug then wrap plenty of tape around the plug to take away the sharp edges of the plug tapering it back to the leads making it easier to get through the valley.

The 3 wire connector to the R/R is a weak link, make sure the connectors are not burnt. Often best to remove the connector and solder and sleeve the wires directly to the R/R wires.

Measuring your charging Voltage at the battery with engine running you should see anything from 13.5 to 14.5 and NO greater than 15.5v DC.

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amazing as i'm in buffalo also !! ☺️

yes, since the coils look different around the circle, it seems like some have fried.

if you ever need any VFR help or local support, call me @ 716 836-0154.  i have a shop, 30 years of VFR experience, all too familiar with honda charging problems, and willing to assist.

regards, jerry

[image: 863317270_Picture1-12-2020236.thumb.jpg.77def83c22f60e898290399bcb0d2389.jpg]

Hi!  Bit of a lurker these days but had myself a 2002 model that I put 200,000km on and burned up a stator or two.

The stator colour is not indicative of it being burned out.  Due to the oil levels in the crankcase, half of the stator is permanently cooled by the oil and the other half is not.  Ergo it gets a burned appearance to it.  It's likely that's where the failures occur due to the higher heat but it doesn't immediately mean anything.

The stator fails in basically one of three ways:

• Short to frame
• Short between phases
• Short within a phase

The way that the stator works with regards to the above is that there are 18 separate poles which make up the three phases (6 for each phase).  Each pole has heaps of insulated wire wrapped tightly around the frame of the stator in a coil.  This wire is thin copper wire with integrated insulation, similar to speaker coil wire.  The wire needs to be a tightly wound coil with no shorts in it in order for the magnetic fields to work.    Around the outside of the wire is an epoxy paint coating to protect the coils of wire.  This epoxy coating is what is becoming discoloured.

Anyway the shielding around the coils of wire can break down.  This either shorts the coil to itself, to the frame of the stator (and therefore the frame of the bike) or between coils.  Either way, what happens is that the stator can no longer generate enough energy.

The regulator/rectifier is sent three separate alternating current feeds from the Stator.  It takes each one and rectifies them to DC using a bunch of diodes, and afterwards regulates the voltage down to 14.4 volts or so (P.S. it's the regulation from high DC voltages down to 14 volts that heats up the regulator and causes it to burn out).

If one of the phases is producing a low voltage, the total final output of the R/R into the bike's charging system drops.  You can have a weak phase (short within a coil to itself) where the voltage is reduced or perhaps an entire phase going dead.

None of this discusses failure of the R/R itself, and there is plenty of material (some it mine from pre-2011) here on the forum about different models of regulator/rectifiers can be installed to manage this problem and reduce or remove the risk of R/R failure.

Hi Kal.

Welcome back after such a long hiatus. Your knowledge of all things VFR is highly respected. 

Best Regards. :fing02:

17 minutes ago, Grum

Hi Kal.

Welcome back after such a long hiatus. Your knowledge of all things VFR is highly respected. 

Best Regards. :fing02:

Cheers mate.  Been a long time indeed.  I shamefully don't ride much at all anymore as I work from home since 2015 and I've also stupidly gotten back into cars as well.