Stator problem?

[BJB]

I have recently acquired a 1989 Venture. I replaced plugs and wires, and replace battery cables as per this web site. I 'thought' I remember that after doing that, my bike would indicate around 14 volts during highway cruising and drop to around 12 in town or idling.

 

Yesterday, my battery seemed a little sluggish on startup and I noticed only 12 volts during highway speeds, dropping to around 10 v in city. During starting, the voltage would indicate 8 volts or less. I suspected a stator problem and looked up the testing alternator by GeorgeS in 1st gen library and I quote:

"At the Large White Plug, with the 3 #14 wires comeing from the Alternator:

Do the following:

Measure the AC voltage on each wire. You can stick the meter probs into the end of the White Plug. ( located just behind left rear cylinder, White connector, with 3 white wires thru it )

With Engine running, you should Read 9 to 15 volts AC, ( thats AC, not DC ) on each wire.

If the voltage on " one" wire is substantially , Lower then the other two, then your Alternator is failing. "

 

I am a little confused about the measuring method but here is what I did. I took apart the plug with 3 white wires running into it. I then measured across the matching wires to the 2 plug halves ie wire #1 from female plug to #1 tab in male plug. This was done while the bike was running. I got 17 volts AC across 2 of these matching wires and nothing or very little on the third...I assume indicating my stator is going or gone.

 

Here is the funny thing though. If I reversed the leads on my meter then I only indicated 7 volts AC on the same two wires and nil on the third set. Why would that happen? I mean, what difference if I measure left to right or right to left on AC current? Weird.

 

So, any suggestions? I assume I have to either buy a new stator or is there such a thing as rebuilt stators? How about trade ins? Anybody know?

Are there any more tests or things to check to confirm stator is fubared?

Thanks.

[Rocket]

So, any suggestions? I assume I have to either buy a new stator or is there such a thing as rebuilt stators? How about trade ins? Anybody know?

Are there any more tests or things to check to confirm stator is fubared?

Thanks.

 

Here is a link, of one replacement unit, that you can use.

 

http://www.buckeyeperformance.com/p01.htm

[Guest tx2sturgis]

...............

Here is the funny thing though. If I reversed the leads on my meter then I only indicated 7 volts AC on the same two wires and nil on the third set. Why would that happen? I mean, what difference if I measure left to right or right to left on AC current? Weird.

 

 

One of the first rules in electronics, is, "Test the tester"...in other words, check your meter on a known source. For AC, that will usually be the 120V AC in your house. Set the meter to the appropriate AC range, (some digital meters are auto-ranging), then insert the probes carefully into a duplex receptacle in your house. You should show something around 115-125 volts, AC. ( USA voltages) Then carefully reverse them, and it should show pretty close to the same reading. AC can occasionally be unbalanced AC, but for this test, if its within a few volts, the meter's diode matrix for AC is good.

 

If its not pretty close, the diode matrix or bridge, in the meter is at fault. This matrix rectifies the incoming AC, so it can be measured by a meter (analog or digital) that can only actually measure DC internally. If the reading was way low in one direction only, your meter probably has a problem.

 

Assuming the meter is OK, then the windings in the stator are bad, and unbalanced readings ( and one dead connection, of course) will be normal for a bad stator. Chunk it.

 

 

 

 

 

 

[BJB]

Thanks tx2sturgis. It is a brand new meter, but I did check house voltage as per your instructions. It tests the same either way. Weird about the stator though. However, you agree that if one of the sets is testing Zero, then the stator is TOAST and I should start looking for a replacement. Are they hard to change?

[rez]

If your looking for a replacement stator....I notice this place selling on ebay regularly. It's called RM Stator (it's in Quebec, Canada). Another popular place is called Rick's Motorsport Electrics (USA). Both places have websites...just google them. I have no experience dealing with them but their names come up regularly.

[BJB]

Thanks rez. I had stumbled across them also. I am frantically searching all this now. Not sure if there is varying quality in these items from place to place. RMStator seems to be selling new stuff @ 1year warrenty. Others were more expensive and wanted a replacement core etc. So far the most expensive is Yamaha OEM parts. WOW.

[Squeeze]

...

I am a little confused about the measuring method but here is what I did. I took apart the plug with 3 white wires running into it. I then measured across the matching wires to the 2 plug halves ie wire #1 from female plug to #1 tab in male plug. This was done while the bike was running. I got 17 volts AC across 2 of these matching wires and nothing or very little on the third...I assume indicating my stator is going or gone.

...

 

I think you should recheck the Voltages. Do NOT unplug the Connector. Place the red Probe Wire into the Connector at #1 and measure the Voltages on #2 and #3. Then let the Wire stuck at #3 and measure it against #2.

 

You can access the Connector Spades from the Side where the Wires go into the Connector.

[BOO]

Sure sounds like a bad stator to me. One of the coils is open.

Make sure before you order though.

Jerry

[BJB]

OK Squeeze. I started bike up and did not disconnect the white connector. By inserting the probes in the end of the connector I measured the following. These are just arbitrary assigned position numbers just to keep things straight.

#1 to #2 12 v AC

#1 to #3 10 v AC

#2 to #3 4 v AC

Not the same readings, but still one set of measurements is quite different from the others.

[Squeeze]

I'm sorry to say, but you need another Stator. It's not that hard to do. New Seals on the the Stator and middle drive Gear(left rear) Covers and your back in Business.

 

Watch out for the lower Bolt on the middle Drive Gear Cover, there has to be a copper Washer.

[Guest tx2sturgis]

One final test you can do, is a continuity test on the connector, and coils of the stator. With the bike NOT running...repeat...shut it OFF...and disconnect the battery ground, just to be on the safe side.

 

Put the meter on the lowest ohms scale, or continuity if it has that, unplug the stator connector from the bike, and test continuity between all the stator leads, on the back side of the connector, then on the front. Connectors pins can get oxidized, and may not test properly on one side or the other.

 

If your meter has a 'beep' function on continuity, its a LOT easier. Apparently, one coil has gone bad, and will probably show no 'flow' thru it. The 2 good coils will show only a few ohms, or less...meaning good, but you need ALL the coils working.

 

Now as far as changing the stator on that bike, there are many more folks on here who can help, and I beleive there are some tech articles too. Good luck.

[bongobobny]

I already bought one of those RM Stators and although I have not installed it yet, I was quite pleased with the dealer. Good price, and prompt shipping. The dealer claims better than stock performance from the unit. I'll find out for sure when I get around to updating mine...

[BJB]

OK. To be clear, I am working on the connector plug with 3 white wires located just under the seat, left side, behind the rear cylinder, in front of gas tank. This connector plug, when taken apart, has a male (blade type) and a female (slot type). The male is connected to 3 white heavy wires which go down to exhaust area and I believe connect to rectifier. The female side has 3 wires (used to be white) which are almost a braided cloth type covering and the wire heads down to a cover just adjacent to the left foot peg.

 

When taken apart and readings taken across the female slots at the lowest ohmeter setting (x10) I can find no resistance and appears to be a dead short. It should be approx 0.36 to 0.48 and even at x10 setting I should see some needle deflection. (Note that I tried two different needle type meters, both cheap, but do register some resistance when measuring bulbs.)

 

 

When the bike is running and the connector plugged together I measured volts AC on the backside of the female connector, ie towards the stator. Again, I get confusing results but I will let the experts tell me what goes on.

Red probe in #1 reading @ #2= 11.5 volts AC reading @ #3=8 volts AC

Red probe in #2 reading @ #1= 3 .5 volts AC reading @ #3=3.5 volts AC

Red probe in #3 reading @ #1= 8 volts AC reading @ #2=12 volts AC

Now don't shoot the messenger here guys....I am just reporting what I measured!

 

I measured voltage DC across the battery terminals and got 12 v or so. With engine running at over 2000 rpms I did not detect any difference. Battery is definately showing signs of getting weaker so I am charging battery now with a 2 amp trickle charger for 1 hour and will repeat this last test, even at 4-5000 rpm but expect no difference. I saw in the download service manual a test for the Rectifier, checking 6 different elements. I do not where this is, but I think I have to actually remove the rectifier to do so and am not sure it is of any worth?

 

So....in your so expert opinions, what is going on here? Does the stator totally quit just like that? Or is there some other connector that has worked loose etc. Bike starts and runs. One other thing, on my last trip I noticed the bike would suddenly shudder like a miss. On more than one occasion I saw the tachometer momentarily jump downwards. I did have some rough running sounds and have put a couple of cans of seafoam through it. I put these misses down as carb problems but maybe it was electrical in nature?

Sorry for the long post, but I am trying to give all the info I can:confused24:

As always all opinions welcome. Thanks.

[Dano]

BJ, went through the same thing with my bike. Replace the stator, it's gone. Rectifier may be OK, but I found mine was shot also. RMStator is the best for the money and shipping. If you are running or are thinking of running a lot of lights, check with Rick at www.buckeyeperformance.com . He carries a high output stator that gives you more power for the "goodies". I believe it was $239.00 when I saw it last night on his website. It's not always a bad idea to pick up an extra rectifier from ebay, 35-50 bucks. They can go out without a warning. Since you have the meters, go ahead and check yours. The plug is right next to the stator plug, yours may have 4 wires or 5 wires, I'm not sure on your year. Mines an 84 and has 5 wires. You can check it at the plug. The unit itself is mounted inboard of the swingarm on the left side of the swingarm.

Check your manual on removing the stator, but here's something the book don't tell you. Leave 4 screws in the cover, almost all the way out (kinda on the corners). When you pop the cover loose, this will keep the stator from holding on to the flywheel (magnet to steel). Once the cover is loose, you can remove the screws and finish the job. Do the same on the install, makes it much easier. And DON"T FORGET THE NEW GASKETs for the left side cover and the middle gear cover, as the middle gear cover has to come off too. Any more questions, feel free to ask.

 

Been there, done that!

 

Dan

[Guest tx2sturgis]

Your stator is gone...and its always best to replace the stator and the regulator/rectifier as a set. Just keeps you from having to do it later. These are both wear items, beleive it or not...and yes, a stator just goes out...just like that, and will cause low voltage, weaker headlights, weak starting, and ignition misfires...just do it. Fix it and be done with it.

 

Yep...its gonna cost some bucks ....we know that.

 

But if you buy a good quality unit, it will most likely last a LONG time.

 

Keep in mind that the stator on a motorcycle is putting out its maximum capacity, at a given RPM, all the time. if its a 30 amp unit, then when your at 3000 rpm or so on the highway, it is putting out 30 amps, constantly. And guess what? Whatever the bikes electrics arent using, such as the headlamp, tail lamp, charging and ignition system, is being 'dumped' or in effect, shorted, thru the regulator rectifier, to the bikes ground. Yes...it is generating current that is not used, but is shorted to the frame...altho some of it is generating heat in the regulator.

 

So...the stator, regulator, and rectifier, are working as hard as they can, ALL THE TIME.

 

Yes...under these conditions, they do wear out sometimes...then factor in heat from the motor, and summer heat too...yep...they go bye-bye.

 

Just open the wallet and pull out a credit card. It only hurts once!

 

 

 

 

[Squeeze]

Oh, i forgot to mention.

 

 

There is a Wire insider the Center Bolt on the Crank. Don't forget to put it in before mouting the Stator Cover. This is the Stator 'Cooler Element'. The early Bikes didn't have had this Wire, and got the Stator fried soon. There was a Factory Recall on this Issue.

[Gearhead]

There is a Wire insider the Center Bolt on the Crank. Don't forget to put it in before mouting the Stator Cover. This is the Stator 'Cooler Element'. The early Bikes didn't have had this Wire, and got the Stator fried soon. There was a Factory Recall on this Issue.

 

Huh? Squeeze, can you 'splain?

 

I agree, your problem is definitely stator. FWIW, The test's I've used all involve measuring across the 3 wires coming out of the engine with the plug unplugged.

 

1) Engine off, check ohms from one connector to another, 3 possible combinations. Should be about a half an ohm each.

 

2) Engine off, check from each connector to engine ground - should be NO continuity.

 

3) Engine on, check AC voltage from one connector to another, should all be about the same and should rise as RPM rises.

 

Jeremy

[Squeeze]

Huh? Squeeze, can you 'splain?

...

 

Jeremy

 

Engine Oil is coming out of the Center of the Crankshaft and is spilled all over the Stator by the Wire which is turning like the Crank. This Oil 'cools' the Stator.

[BJB]

Jeremy,

My stator measurements fail both #1 and #2 in your post so I believe a new stator is in order. My measurements on the rectifier seem to indicate it is OK. However, some web sites that sell stators, indicate that with the newer high output stators, a new and better rectifier is needed and these range from $80 to about $160. Not sure about the rectifier yet.

 

Plan on going to a nearby Venture rider who has an 86 and compare some measurements on his unit....just to make sure I am measuring at the correct places and get the correct readings on his bike.

[BJB]

For those who have been following this topic, I managed to get some measurements from another 1986 Venture. Measuring across the 3 white wires from the stator (female end of plug) I did not get any ohm reading at all. It is supposed to be 0.40 or so (used a digital multimeter this time). However, measuring from any of those contacts to ground on my bike produced a dead short..not so on his bike. Also with plug connected and bike running, we measured 12.6 V AC across any 2 of the white wires and it did not matter what direction this was taken. The readings from my bike were posted here earlier. So, I have convinced myself that my stator is indeed toast (as everyone here has already stated more than once) and have ordered a new one today, as well as two gaskets. Should be back on the road in about a week. Hope this info helps the next person who has trouble.

[Guest tx2sturgis]

...So, I have convinced myself that my stator is indeed toast (as everyone here has already stated more than once) and have ordered a new one today,....

 

'Bout time....I was thinkin we'd have to all ride over there and bop you upside the head!

 

[Dano]

BJ, when you take it off, you will definately notice a "burnt" spot on the windings, this is where it is shorted out.

 

BTW, does anybody on here know where we can send in our old stators for rewire or re-cycle? I hate to just throw it away, just needs to be rewound to put into service again. Might even save some money in the long run getting it rebuilt and on the shelf for a spare.

 

Dan

[MiCarl]

I would think a shop that repairs electric motors might be a good place to check to have a stator rewound.

 

BJBoomer, when you put your replacement stator into the cover pay close attention to the grommet that seals where the wires pass through the cover. My 89 apparently had the stator replaced at some point. The grommet doesn't quite fill the opening in the cover, leaving about 1/16" gap between the grommet and the engine. This created a persistent (and difficult to find) oil leak. A bit of RTV on the flat edge of the grommet solved my problem.

[6m459]

I had the same problem this time last year.

 

In prep for the repair job, during the preceding winter, I had bought a used stator & cover on ebay for $5 or so just to get a look at the parts. When I came to do the job, I bought an aftermarket stator from RMStator in Quebec. Wisdom and marketing propaganda said that a/m was the way to go, extra output, heavy duty, yada yada yada. Fell for it hook line and sinker. Not to mention that local Yam dealer wanted $400 Cdn for the OEM part!

 

I installed the a/m stator and got about a month of good service out of it when it failed. I phoned the RMStator people & found that they were reselling stators made by www.electrosport.com in the USA. Electrosport honoured the warranty directly and replaced the failed unit, no arguments at all, BUT IT TOOK OVER A MONTH for the round trip.

 

In the meanwhile I had a big (and partly dismantled) paper weight parked in the garage, so I thought what the heck, I'll put the $5 ebay stator in and see what happens.

 

 

Long story short, the bike is still running on the $5 ebay stator to this day! (Knock wood now) The replacement a/m one is in my parts bin. I'll part with it for $100 Cdn, but don't really advise it.

 

Oh, and BTW, you can see some pix of my stator swap work at:

 

http://www.orbitonline.ca/~bjh/rmstator/

 

 

Hope this is of some help.

 

Brian H.

Uxbridge Ont

[BJB]

Installed new stator from RM today. Just finished and fired it up for a quick check on oil and leaks etc. Voltage meter is back up around 14 volts again which is great. Will have a better idea tomorrow when I can get the revs up and check with the voltmeter at the battery terminals. Thanks to all who posted and PM'd me with great ideas, suggestions, and friendly help. This site is great.