Newbie with Electrical questions??

[Richyzfr1000]

Hey Everyone Just found this sight and I will be coming here often..

I was hoping someone could help me. I recently purchased a 1980 Yamaha XS 1100 Midnight special, the bike is in amazing condition but the speedo, tach and headlight are not working. Everything else does. It seem that the Hi / lo beam portion of the left side switch is not getting power, when I apply power to the switch everything lights up. Any ideas on what this could be? The fuse is fine, I swapped out the lighting box. Could this be the headlight relay? Does the headlight relay also control the Speedo / tach lights? Any thoughts would be greatly appreciated, I am doing my best but I am not the greatest when it comes too electrical stuff

I just thought I would get peoples opinions before I spent more money..

[bikerphil]

Tach: Gets it's signal from the alternator. Check to see if you have 14.5V at the battery when engine is running at 4K RPM. If it's much lower, the connectors from the alternator behind the fuse panel might be corroded or melted.

Headlight: The headlight relay also is triggered by the signal from the alternator via a latching diode. A quick way to bypass this relay is to jump the red/yel & blu/blk wires at the relay. The relay is under the fuel tank up by the steering stem. Disconnect those 2 wires from the relay 'n hook 'em togeather. Headlight and guage lights should come on with the key turned on. It is highly recommended to clean & di-electric grease every connector on the bike, including the grounds.

[renegade_xs11g]

headlight, dash lights, and the tach itself (rpms) are dependant on the alternator....if not working, with engine running, you may have a faulty alternator....
alternator has three parts: field coil, stator coil, and the regulator/rectifier
the reg/rect is the weak link
Trouble shooting the alternator
This link should help

[CatatonicBug]

I had a similar issue. As Phil mentioned, the big white connector behind the fuse panel can get corroded, and loose connection. Mine was so corroded that it heated up and melted the connector. I cut the connector out and soldered the wires together permanently. That fixed my tach problem. It's one place to look at least. HTH

[Richyzfr1000]

Awesome, Can’t thank you enough for the help. I have been up and down the wire harness checking everything and everything looks good..

I just tried jumping out the relay and everything worked. Does this mean I have a bad relay? Dash lights came on and when the bike started the headlight came on as it is supposed too.

[bikerphil]

Does this mean I have a bad relay?

Gotta check your charging system first to see if it's putting out. If it isn't, the relay can't function properly and the tach won't work either.

[Richyzfr1000]

Cool I will check it out in ther morning.. Thanks again...

[oseaghdha]

Awesome, Can’t thank you enough for the help. I have been up and down the wire harness checking everything and everything looks good..

I just tried jumping out the relay and everything worked. Does this mean I have a bad relay? Dash lights came on and when the bike started the headlight came on as it is supposed too.

If you jumped the relay, the headlights and dash lights will come on with the key.

[TopCatGr58]

Hey Richy,

As has been stated, the charging system is what needs to be checked out. However, it can fail several places. The 3 big white connectors BEHIND the fusepanel are known for corrosion, even melting, they are where the power comes from the ALT into the system. Next is the reg/rect unit, they are also known to fail/die. There is a member on here that makes a terrific aftermarket replacement, much stronger than OEM, you'll find info in the parts for sale forum STICKY thread! But pull the gas tank, the reg/rect is under there, remove, clean the contacts especially to ground/frame, the bolts that secure it to it, etc.!

It's more rare, but the diode in the wiring harness can go bad, so IF you find you ARE getting good charging current/voltage, then it might not be getting to the relay.
T.C.

[Richyzfr1000]

Hey Guys thanks for all the help, everything checked out and with a new Relay I was fine... Now... Gas is pouring out of my airbox I took the air filter out and it is coming from my #2 carburetor... Any suggestions?? could it need a needle vavle and seat?? Again any help would be appreciated..

Thanks

[DGXSER]

Yep, it may very well need a new needle valve and seat, very least you will need to pull the carbs, open the float bowl, remove the pin holding the float in and pull the needle valve and seat and clean, clean, and clean.

As was told to me, and I only half believed it until I experienced it, cleanliness in these carbs and these seats especially is a requirement! Ohh, and automotive fuel line tends to break off little pieces when putting it on the fittings of these bikes and cause that very problem. DAMHIKIJK.

[Richyzfr1000]

Thanks.. I figured as much.. ok more work to be done..

[Richyzfr1000]

Amazingly I just wacked the carb like i used to do in my motoX days and it must have knocked the float free. Just got it running, ran fine with no leaks.. The bike sounds amazing.. I am sure I will be back but thanks for all the help..

[DGXSER]

Awesome, forgot about that possibility, when the carbs go dry the float can hang up. Glad you got it fixed so easy!

[Richyzfr1000]

I hope it stays that way.. I will run it again tomorrow then do an oil change.. It realy is in great shape only has 18K miles and was babbied.. So I hope everything else goes well.. I cant wait for the snow to melt.. I am going crazy..