Headlight troubleshooting

Hello all. Two days ago I ran wide on a turn in a canyon and slid on the gravel laying my 81 xj550 Seca. Bike is basically okay, however, the headlight no longer turns on. The dash cluster still works fine. I looked at the bulb on the headlight and it seems fine and I also checked for continuity on ALL the connections and everything checks out. I even tried replacing the bulb and it still doesn't work. Any ideas on how to troubleshoot this.

Note: I completely switched out the fusebox for a modern blade style fuse box and it works great.

 

Never mind. I figured out the problem. The fuse for the headlight was no good. I replaced it and all was good. Come to think of it, all my problems were solved when I replaced the fuse box. I literally could have saved hundreds of dollars if I just replaced the fuse box. I'm surprised I couldn't find any articles suggesting this to solve charging problems concerning old bikes. Most people say check the battery first but no 'check fuse box" suggestions.

 

There are plenty of "Replaced Fuse Box" threads. Many people upgrade to spade style fuses as opposed to the original glass type. I believe xj4ever sells a kit...

 

I think we did go astray there.
I assumed that you had read The Information Overload hour already, and had checked the fusebox.
My mistake.

 

I'm sure there's post about replacing the fuse box but specifically to fix a charging problem?

 

That is good news, it seemed like from your original description of the event that it was a total loss.

That is why this thread is often recommended as required reading

https://www.xjbikes.com/forums/threads/the-information-overload-hour.27544/

"- THE ROOT OF MANY EVILS: REPLACING YOUR ORIGINAL FUSEBOX:

This should be on the very top of your "to-do" list, it will save you untold hours of grief and frustration down the road (no pun intended!):

Replacement Fuseboxes:

Upgrading your electrical system couldn't be simpler with one of our aftermarket style enclosed, waterproof fuse panels.....bringing your bike a long way up to 21st century standards of electrical wiring, and helping to prevent and eliminate annoying, frustrating, and down-right dangerous electrical issues that worn out stock fuseboxes suffer from."

And I would agree, but sometimes not knowing all the issues (starting problems) makes for a tough call. Simple things over the internet when exchanging words can often lead to some misdirected paths.

 

yeah, it's unfortunate. I posted a thread about my experience to help the next person. As a newby mechanic and new to riding all I put in search engines was "81 Yamaha 550 Seca Charging issue" and you're kind of at the mercy of whatever comes up. I'd say about 90% of the stuff I came across said to check the battery first but like I said before, I'm surprised not one thread mentioned to check the fuses when fixing charging problem on old bikes. It seems like it should be a pretty common first thing to do. But what do I know. Thanks for your help.

 

Well you know plenty, and I think this one taught all of us something new so thanks for sharing it with us. Like I said earlier it was an unusual fail and that is why you likely did not find your answer in a any of the threads here. It really took some pretty special circumstances to occur.

One interesting clew we had earlier that you replied to was when asked if the voltmeter on the bike was going up with revs you replied with a yes. Unfortunately, the 550 schematic has errors and doesn't really show how the meter is connected. From your answer I think it is safe to assume it is connected to the switched output of the ignition switch, which make sense or it would read 12V all the time. Additionally, if the V1 V2 voltages had been checked per the FSM (which none of us suggested) we would have seen an output from the alternator indicating it was actually working - perhaps even a bit overvoltage without the dampening load of the battery. Seeing an output there (the regulator) and not at the battery would have been another major clue.

And just a side note - Yamaha cautions with bold lettering to never disconnect the battery on a running bike. If the main fuse is effectively disconnecting after starting this would be the same as disconnecting the battery. Whether disconnecting the battery is safe or not is quite a controversial subject, but in this case it did not seem to cause any damage to the TCI, which would be high on the list as a component that might be damaged from spikes or excessive voltage.

Edit: Looking at the built in meter again and the poor schematic a better guess is that it connects to the output of the signal fuse notated by a Br wire and shared with the neutral light.

 

http://lumien.se/stuff/xj550/XJ550ElectricalDiagram.html

shows voltmeter hooked to neutral bulb and diode block (brown wire) black wire to meter bulbs black wire for ground

 

I did a Google search using your exact wording (site: xjbikes.com charging problem) and the 1st answer in the 3rd thread listed recommended the fuse box. Its out there, you just need to search more diligently.This is the 3rd thread as supplied by Google.
https://xjbikes.com/forums/threads/crazy-charging-problem.37484/

 

That is one of the more annoying things about getting search results, particularly when using a forum-based search tool.
Oftentimes using the right combinaton of keywords, and the correct set of constraints, is the only way of getting the results that are really helpful.
Sometimes I miss the days of diving into Usenet and FTP sites. It was a good training ground for figuring out how to find the information that you needed (and finding some information that you never thought you needed until you found it). Modern search engines are convenient, but not always reliable.

 

Also why it's always recommended to keep all questions/answers together in one thread about a particular bike so that it can easily be referenced when trying to help

 

I think the below drawing is the same and they left a couple of connections out. The Br wire only goes to the voltmeter and the neutral light, it should have been extended upwards to connect to the Br wire going to the fuel gauge and connector. The B wire from the voltmeter also dead ends, there should have been a circle annotating a connection to the B wire from the fuel gauge and connector. So, I guess it is safe to assume that the 550 voltmeter is connected to the signal fuse output. The only logic for connecting it there was that it was easy as the signal power was already routed to the gauges.

 

That's because I just wrote that post.

 

Did you click the link? That isn't your thread, and you didn't post in it.
The last post is from 2012.