elec question: headlight and key on

[cywelchjr]

Sorry TRdriver, I guess I was being a bit generalistic in my post.
Your bike'll be a 3H4, so may have the gizmo fitted.
Mine's a 3H3, which according to all the info on this site, was a US market bike and it doesn't have one of those relays.

Then it would be a modified bike, as ALL U.S. market machines had the headlight relay. Federal law required all bikes sold in the 1980 model year and later to have the headlight on when running. The XS1100's had that included from the begining, but IIRC you could turn the switch for the headlight (if it has one) on to force the headlight on before the engine is running on the 78 and 79 models, but once it's on it stays on till the ignition is turned off as it causes the headlight relay to energize and latch.

But, ALL 1980 Yamaha bikes sold in the U.S. had the headlight relay system (at least all the street bikes).

I'd guess that yours has the socket for it, with a wire plugged into it to bypass it (it's easy to do, just takes a single jumper which makes it look like the relay is there and always latched on). I ran my 1980 XS400 like that for about 3 years because the diode went bad, and I didn't want to dig into the harness to replace it. You can also unplug the relay to keep the light off with the engine running if your doing tuning work and don't want the load of the headlight on the system.

[Eveready1100]

Then it would be a modified bike, as ALL U.S. market machines had the headlight relay. Federal law required all bikes sold in the 1980 model year and later to have the headlight on when running.

Mine was manufactured 3/79, before it became mandatory

[natemoen]

Mine was manufactured 3/79, before it became mandatory

Mine was made in 11of 77 and mine has the relay. It does have the headlight on off switch as well but that switch only controls the light BEFORE the engine starts. Once the engine starts the light cannot be turned off.

[cywelchjr]

Mine was made in 11of 77 and mine has the relay. It does have the headlight on off switch as well but that switch only controls the light BEFORE the engine starts. Once the engine starts the light cannot be turned off.

What I was going to say. It became mandatory for all bikes sold in the U.S. in 80, but all U.S. XS11's had the relay from the factory. If you don't have it, it's been modified or is not really a U.S. bike.

[natemoen]

What I was going to say. It became mandatory for all bikes sold in the U.S. in 80, but all U.S. XS11's had the relay from the factory. If you don't have it, it's been modified or is not really a U.S. bike.

yeah, I was trying to argue that for you.

[Eveready1100]

Sorry guys. I didn't mean to upset anyone. I guess mine must've been altered before I got it. I'll investigate further the next time I've got the tank & seat off.

[natemoen]

No one is upset. Just clarifying.

[clcorbin]

Hi Redshirt. It's the later model Specials that have the "motor running only" relay for the headlight fitted. Your '79 should light the headlight without the motor running and ignition on and controlled by the switch on the right switchblock.
Regarding the indicators, I'd be checking all the earths from them plus making sure all connectors are tight

I can definitely say for my US model 79 standard, it has the head light relay and the headlight will NOT come on until the engine is running. It also stays on, even with the engine off, until the switch is turned off.