Bonneville America Forums Forums Technical Forums General Tech Pulsating lights

hey guys, quick question. I just took my bike out of storage and out for a run. My lights were good for a while but then I noticed they started pulsating. Especially with my light bar on. At idle seems OK but when I start to rev it a bit they dim then pulsate. Would this be the battery. Same one since 2005. Or maybe a short. I hate wiring problems.

Willy/BikerT

It sounds like the battery to me. Do you have a charger? I know most batteries are only good for four or five years. But, if you can put a full charge on the battery and see what happens.

I shall give it a try. thanks

Well I charged the battery up full and it still does it. Now I notice it pulses on idle especially as I see the lights reflection on a wall. At the slightest increase in throttle they also dim. I will take it out for a ride tomorrow to see what it does. A friend of mine is letting me use another battery to compare.

Sounds like your R/R or stator may be bad
- check the battery volts with the bike running at idle and at say 4k rpm and report back with the numbers

Based on the results can give you further tests to determine which (if appropriate)

OK, with the bike not running 12.63. Cranking 10.43, idle 12.9 rev. up to approx 4000 the same. letting off throttle 13.5 to settle back down to idle 12.90. After about 10 times checking, cranking was only at 10. once is was 9.5 so the starter kicked out. I do remember reading somewhere if cranking amp is 9.5 battery is no good.

The 12.9 is definitely low

We need some more checks now

A very quick test for you all if you ever suspect a stator failure:
When they go, they typically burn a coil(s) like in Keith's pic



when that happens the winding shorts to the core.
Normally the windings should be completely isolated from the core. The core is obviously phyysically connected mechanically to the engine so you can check to ensure that your windings (measured through the connector) are isolated from the engine.
So if you unplug the stator output connector, set your meter to read resistance & you should NOT read a short (it should be infinite resistance, open circuit) with test probes between ANY of the three termninal pins to engine ground. (you can use any of the three pins because there is less than 1 ohm between each of the pins anyway - so no consequence whichever one you pick - either all will read open to ground or all will read short)
It is not 100% guarantee of being good if you do read 'open'; however is absolute certainty of failure if you read short.
If it does indeed read 'open' - as it should - then you go on to a further test to check the actual output volts:
set meter to AC V (~ symbol) and start bike (You do not need stator connected to run);
then read between the three combinations of two, of the three pins
i.e. 1-2, 2-3, 3-1. (does not matter which you designate as 1,2 & 3)
The voltage should be 20-25V or so at idle - absolute number will vary by model and engine rpm so the important factor here is that all three read the same.
If you like you can then raise engine speed and check at higher rpm - the voltage will be higher but again all three readings should be virtually the same (but ensure the throttle speed is locked at same for each reading)
If you find one that is significantly different from the other two (at the same rpm), the stator is suspect.

The majority of the time, when failed, you will get the 'short' as per the first test.

---

You can follow the cable from the output of the stator at the top of the right side case until you come to the 3-way connector that plugs into the R/R (connectors should be approximately below the carbs)

Sorry this wasn't on line. I PMed Ken and Kieth, "I am going to do some testing this weekend. Someone is helping me read the tester as I am absolutely electrical illiterate. Can't I just pull the cover off to see if the stator looks like it does on the post or is there gasket replacing. Also I noticed. After I unplugged the connection under the seat. I started the bike and the lights did not pulsate."

Ken's reply " Hi Willy

If you unplugged the stator & it no longer modulated the lights, it probably is strong indicator that either stator or R/R is bad - however it could still be either one.

It would be good if you could do the electrical tests I indicated - the very first one, not even measuring the voltage would give you same result as opening up to inspect it - just put meter on ohms and put one probe in ANY of the three terminals in the stator plug and the other to battery negative (or just touch the engine cases) - if you read short (same reading you get if you just touch prpbes together) then the stator is definitely bad.

Cheers
Ken

Keiths rely " Hey ya Willy!
Yeah, you CAN pull the cover off to visually inspect the stator but there is a gasket involved. If you do this, leave the bike on the kickstand so it's leaning away from you. That way you lose little to no oil at all. The info you stated here should be on the forum too, so the guys can see it and comment on it. Especially the bit about the lights not pulsating when you unplugged that connector!

Cheers, Keith

That's not the end of the story!!

Ok, the rest of the story. Just what is going on here. Now my bike won't start. Started yesterday. not great but did start. I think this is isolated from these other issues. Some quick info. Bike was in storage last year. Carbs were drained by running out. Took it out of storage last week. Started on one cylinder then the other kicked in. Rode it for 20 km. then noticed the lights. Did a fews checks to deal with that issue. Now it wont start. Bought a new battery. Still wont start.

Shutterbug [Don]'s friend, get this, "Don" stopped by and helped me drained the bowls. Filled them back up. Won't start. Pulled the plugs. Spark was good on both. Right one was wet, left dry. Cleaned the plugs. Pulled the main and pilot out of left carb. Main looked good. Pilot was a see through but very small so we cleaned it out. Reinstalled everything. Bike still won't start. Plugs pulled. Now both are dry. Apparently gas is not being pumped into the heads.

Not sure what to do. Today I will put in some new plugs and give it a try. Maybe put a small amount of gas in the cylinders to get it fired up.

Ok, set the gap, put them in fired right up. Now some testing.

Ok, my ohms meter reads a # 1. when turned on. When I touch the probes together it reads 0. When I did the test the meter read 1.

and the voltage for the all 3 prongs where all the same 16-20 on low idle. defenite increase when opened up.

OK Willy, good news on the stator - that looks good at least.

Are you still seing same issue with the lights doint the pulsating thing?

Next check would be the R/R
Unplug connector to it - it might be easier to remove it from bike for testing.
Again set your meter to resistance (if it has a 'diode' range' then that is the best one to use for this test)
You will want to measure with one probe in each terminal of the input wires to the the positive & negative output wires:

Red Probe/Black Probe

Black1/Black/Red
Black1/Black/White
Black2/Black/Red
Black2/Black/White
Black3/Black/Red
Black3/Black/White

Then reverse the polarity of the test probes:
Black Probe/Red Probe
Black1/Black/Red
Black1/Black/White
Black2/Black/Red
Black2/Black/White
Black3/Black/Red
Black3/Black/White

None of these should read short:
Best if you just post the results

As I look again:

Quote:

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... and the voltage for the all 3 prongs where all the same 16-20 on low idle. defenite increase when opened up.

---

You need to be a bit more definitive there Willy - 16-20 is quite a big range
i.e. if one was 16 and the other two 20, that would constitute an issue.
The three should be the same within about 1V at the exact same rpm (easiest measured at idle speed)

Oh sorry, yes they were all the same.

With new battery, what are you getting now for volts across it with engine running at idle and 4k?
Still same?
And lights still pulsating?

Almost would have to be the R/R at this point, given the clean bill of health on the stator
But we can see what the results of the tests above show before being sure one way or other

I double checked the voltage. They are all the same. 16 very low idle. 20 I guess normal idle. When I increase throttle definitely goes up 40 +/-. I can't check all 3 at the same rpm setting as I don't have a tack.

Also I took the bike down the road and had someone visually look at my lights as I come toward them and they are not pulsating. At idle they do and when I twist the grip a bit they dim but don't pulsate I guess because of the higher rpm as if I was riding/as tested.

Ok now, what's my R/R?? where is it.

Also strange, I start the bike up in the shop at idle it only pulsates lightly looking at a reflection of the light and it definitely pulsated when i rev it up, not a steady pulsation but intermittent. hit and miss, bright then dim.

I meant what is battery volts now with engine running at idle & at 4K.
Did you see any issues with the connector plug to stator - or with the connector plug to the R/R?
The Rectifier/Regulator - the square metal block with the cooling fins on it

Yea, guess I should read more than I write. New battery pretty well the same as the old one. 12.68. When opened up 13.00. Stator plug in great condition. lots of lube on it. I am taking the R/R off tomorrow. It plugs in in-between the carbs somewhere I gather or does it disconnect at the block?

I wanted to thank you for all your help thus far.

Ken, you are doing a bang up job on helping Willy! One thing not mentioned in this thread however, is a small but useful mod many have done with positive results. It is the issue of running the red/black wire coming from the R/R directly to the positive side of the battery. For some of us, this cured the problem of the battery not getting maximum output from the R/R. Rather than the R/R's r/b wire running all the way up the harness to the headlight bucket and back again in a light gauge wire, it takes a much shorter route to the battery in a heavier gauge supplied during the mod.

See picture below (supplied by Dave (Roadworthy)). That red/black to red wire comes from the rectifier before the clip and goes directly to the battery's positive terminal.

I agree that mod will give a better voltage at the battery - however if less than 13 (as appears to be the case), coupled with the observed visual pulsing of the lights, there appears to be an actual failure here.
Most respectfully, that wiring mod will give some improvement to a working system - cannot fix something that is broken

Here are the results. When R/R disconnected, lights do not pulsate.

Red Probe/Black Probe/

[resistance]

Black1/Black/Red-nothing or open
Black1/Black/White-3.24 mega ohms
Black2/Black/Red-nothing
Black2/Black/White-3.26 mega ohms
Black3/Black/Red-nothing
Black3/Black/White-3.21 mega ohms

Then reverse the polarity of the test probes:
Black Probe/Red Probe

Black1/Black/Red-3.2 mega ohms
Black1/Black/White-nothing
Black2/Black/Red-3.4 mega ohms
Black2/Black/White-nothing
Black3/Black/Red-3.4 mega ohms
Black3/Black/White-nothing

Diode setting
-nothing
Reverse- nothing

Just to be sure, this is the meausurements into the R/R itself, right?

The diode readings should be ~ 0.6V forward and 0 reverse.
The diode setting sometime doubles as the 'beep' mode, but there is perhaps another switch to differentiate between them?
(Do you have link to the model of your meter?)

You might try the resistance on 2k range,

But fact that you have no shorts - and that all the diode juntions are all consistent with each forward & reverse is a good sign.
It's not really looking like much wrong with the R/R.

Check your ground connection to the motor and also the battery terminals are secure & in good order.

Yes, I did not take it off as I did not want the challenge of feeding it back in through that small opening up through the rear tire and the frame. It was only unbolted and testing was done in between the carbs. I will retest as mentioned. thanks.

I'm having the exact same issue with pulsating lights but mine only seems to do it at speed and it only does it with the light bar turned on. So far I have cleaned the battery contacts, rectifier connector, and checked some of the wiring. I found that I had a badly corroded wire on one of the terminals where the stator plugs in to the wiring harness so I cut the wires and re-terminated them. Had to remove the connector housing and label the wires to connect them back up properly but I'm going to try it out tomorrow and see how she runs. I haven't changed the battery yet and thought that might be the culprit (almost 3 years old) since I had to bump start it a while ago but the battery showed a good voltage after putting it on my trickle charger (only took about 20-30 minutes top off the charge).

I also used a multimeter to check the rectifier (as per one of the above posts - thanks!) and it checked out fine. If the battery is still good and she starts then I'll check the voltages across the stator. Tried to take the rectifier out but the connector was too big to fit through the space the wire goes through. Looks like I would have to remove the engine from the frame in order to pull the rectifier without cutting the wire to the connector.

BikerT - at least based on your reported data suggests the stator & R/R both look normal

- per the findings of EnglishYankee, another problem that also often manifests itself is of the interconnects;
so important that both the 3 -way stator connector and the mult-pin input/output connector of the R/R are in good condition, with no sign of any corrosion or arcing/burning damage.
Having one of the stator connector terminals (at either interface) being bad, has the exact same effect as there being one of the three stator windings, or legs of the R/R being dead.

English Yankee - when bike is started & running, what does the battery voltage measure at both idle and say 4k rpm?

One quick ps on re-terminating wires into new connector if it becomes necessary: the stator wires can all be interchanged with no consequence; it is immaterial that they be matched to original connector location.
Also, be sure that these connections are stellar - ideally a high-quality crimp. I usually crimp my terminals and then ALSO solder them.

My bike is fixed, Ken, you have gone above and beyond. So I thank you personally to keeping me on track in trying to find out what it was. My hat is tipped to you also Kieth as my bike is now fixed. I can't actually pin point what it was though as I did a number of checks and a couple fixes.

I started with the head light. All good except for the amount of rust inside. Cleaned it up.
I removed the engine ground. It did look fine but sanded it up and tightened it up.
I took the tank off and did a visual check on all the wires I could see and it all looked fine.
Next I cleaned the Starter solenoid. One of the terminals were rusted so I took it off and cleaned it up.
Next the fuse box. Pulled all the fuses. They all looked fairly clean except for the 30 amp. Battery fuse. One point was blackened and dirty. Replaced it.
Put it all back together. Put the meter on the battery. Started it up. 12.9. rev it up a bit 14.2. dealer told me that's where it should be. No pulsating. rev it up a bit and the lights get brighter, not dimmer as before.

Just remember I was not alone. I had the help of a friend /electrician and you guys of course. I will keep my fingers crossed.

Safe riding!!

See you on the road Willy.

I ended up putting a new battery on anyway since I'm heading the the GA rally tomorrow. I was able to start the bike in my garage Tuesday night but didn't go out because it was late and storming (thunder, lightning, wind and chucking it down with rain, the works). Tried to start her up early Wed afternoon but she wouldn't turn over. That could have been partly due to the old gas in the tank since I haven't ridden in a few months. I think the only reason I was able to start her up on Tuesday night was because I had just taken the battery off the trickle charger (was getting 12.68V without the bike running). I had a few issues with getting the bike to start the last time I rode so I wasn't sure if it was the battery or the pulsating (probably a little bit of both). She started after I put the new battery in and some new gas (with a little SeaFoam to clean out any buildup). Took a short ride as the sun was going down and did not notice any pulsating after it got dark. I agree with the solid connections and I only crimped the connectors on since I'm heading out in the morning but maybe I can convince Chy to help me do a little soldering since my skills with that need a little work. Thanks for confirming the stator wiring harness configuration, all the wires were the same color so I kinda figured that it might not matter but didn't want to take any chances.

Good deal on getting it resolved EY
Sounds like the wires/connectors may have been the issue regarding the pulsing lights?