Headlights not working

[mayhem8]

Noticed when I pulled in from a ride today that my headlights weren't working. Turned the bike off then started it again, and the headlights lit for about 1 sec and went back out again. Same thing after a couple off/restart attempts.

Did some reading here and someone mentioned to turn the key on and tick the starter and the lights should come on, and they did and stayed on. Then I started the bike and they went off again.

Saw something about a weak stator possibly causing this and was thinking that my battery might be drained if that were the case, even though it does crank fine. I connected the battery to a charger and it drew about 10 amps for about 10 mins or so but went down to 0. The battery was new last year but was drained at one point (beginning of riding season) from sitting. It did appear to take a full charge.

With the battery fully charged I started the bike and the lights came on and stayed on. Will try checking the battery before and after starting and hoping I don't have a weak stator issue. Any thoughts/ideas of other things to check/try appreciated.

[mayhem8]

It was bugging me so I checked the voltage. With the bike off the battery read 12v. I started it and it still read 12v, but the idle was low so gave it a little choke to bring the idle up and it read 13v, It's a cheap multimeter so I don't get 10ths.

In a car when the alternator is charging I'll usually see 14v. Should I expect to see the same on the bike?

FWIW - The lights did come on and stayed on, but if it is a weak stator, I suspect this problem will return after a ride or 3.

[cushman eagle]

With the bike running 2500-3000,the battery voltage should be about 14.5-14.7.
If it is only 13 at that speed,you may have a weak alternator.
But I would first check for clean connections between the alternator and the battery.

[cushman eagle]

With the bike running 2500-3000,the battery voltage should be about 14.5-14.7.
If it is only 13 at that speed,you may have a weak alternator.
But I would first check for clean connections between the alternator and the battery.

[SgtSlag]

Convert the majority of lights to LED's and you will gain voltage at the battery. I changed out everything, except the instrument lights, to LED's. The headlight LED runs at only 20/35 Watts (around 2x the Lumen output of the incandescent bulb), versus 50/55 Watts for an incandescent bulb. I gained around 1 Volt of charging voltage after I went with the LED's. The other point is that I likely will never need to replace a light bulb (except for the instrument cluster) ever again.

Make certain that you use LED's which put out equal or greater Lumens than the original incandescent bulbs. The LED's not only lower the current draw, but they have a Mean Time Between Failure (MTBF) of 30,000-50,000 hours; incandescent bulbs have a maximum MTBF of around 9,000 hours.



Cheers!

[GrandpaDenny]

The only problem with LED headlights is you can't see where you're going. They illuminate wonderfully everywhere except directly ahead.

[mayhem8]

Thanks for the replies. Sounds like next steps will be to check the voltage again with a better voltmeter and the engine revved between 2500-3000 rpm. I replaced the battery near the end of last season and the bike is always garaged so the connections should be good, but will double-check them.

For some reason I thought the charging system was driven by a stator in the bowels of the engine. Googling it shows something that looks more like a car alternator and it "seems" fairly accessible and is only about $125 for a new one on Amazon.

Looked at the online manual from the PDF here and there appears to be a 10a and 30a fuse in the alternator circuit, so just need to see if I can find those and verify those are OK.

When I get a chance I'll do a search here for "alternator", but if someone has replaced one and can let me know how big a job it is, it would be much appreciated. I seem to remember reading something about where it connected to the engine was a royal PITA.

BTW - I have 2 LED lights mounted in the fairing in the side vents and I rarely if ever drive the bike at night, so would just be happy if it worked stock, but the LED headlight may be an off-season project. For now, I'll probably just charge the battery as needed and finish out the season if it winds up being the alternator.

[cushman eagle]

Hi,mayhem8,changing the alternator is a very easy and straight forward job.
Remember to disconnect the ground wire at the battery first.
When you buy an alternator,try to find out if it has roller bearings instead of bushings,which some have had .The ones with bushings tend to have a shorter life.

[mayhem8]

I watched a generic alternator video on YouTube and was reminded that an alternator has an exciter coil. This is essentially used to create an electromagnet that the main coils (armature) passes through to create the 12+v. The 10a fuse was likely for the exciter coil and the 30a one for the output of the alternator.

If either of those fuses is bad then the alternator won't charge the battery, so hopefully it will just be one of those. I usually am not that lucky though.

[mayhem8]

So I may have gotten even luckier than it being a fuse. I checked the fuses and all looked good, but to get the fuse lid open I had to move a crimp on connector on the negative battery terminal a bit.

All of the connections were super clean, as expected, but probably not as tight as they could/should have been. I tightened down both battery terminal leads and started the bike and was reading 14.?v at the battery. Before I was only seeing 13.?v.

May have been as simple as a loose battery lead, but seems to be fine now.

[Nails]

These kinds of things can be weird. I've seen poor connections that would pass a big current (starting) but not a small light.

[cranky]

... you NEED dielectric grease on those battery terminals!!!! ... or you will
continue having "lose" cables!!!! Use a cleaner brush, clean'um up and put some
grease on 'um.... good for a long time! JM2C

So I may have gotten even luckier than it being a fuse. I checked the fuses and all looked good, but to get the fuse lid open I had to move a crimp on connector on the negative battery terminal a bit.

All of the connections were super clean, as expected, but probably not as tight as they could/should have been. I tightened down both battery terminal leads and started the bike and was reading 14.?v at the battery. Before I was only seeing 13.?v.

May have been as simple as a loose battery lead, but seems to be fine now.

[cushman eagle]

Good Call, cranky,That does a good job keeping connections working

[Dan66]

Strangely, I also had a problem a couple of weeks ago.
Headlight went out... in the dark...OBVIOUSLY!
After 30mins messing about on a garage forecourt, which I was incredibly lucky to be near, it came on again.
I always carry a few tools and bulbs, but the bulb was fine as is everything else, that I can see in any case.
Never had a problem and been fine since. I’ll dig a little deeper one day, my best guess is a dodgy connection, but I couldn’t find one at the time.
One of those oddities that may never come to light... pardon the pun !

[VoyKimmer]

10 pin connector

[mayhem8]

I actually have and always use dielectric grease on all of my battery and bulb connections (car/motorcycle/snowmobile/etc). That, and super clean connections had me surprised it was a battery connection problem, but all I did was tighten them and the problem went away. I actually saw the running voltage at the battery go from 13v to 14v after tightening the battery connections. Stuff does get wiggled/moved while in there, so who knows, perhaps it was something else and the problem will return. Hope not.