I've just got this '74 DT360, which stood for 40-odd years and was seized. Having managed to free it off I'm trying to get it running, but have no spark. There's a black wire with a white tracer that runs out of the kill switch and stops in a bullet connector near the frame down tube. I can't se anywhere obvious for it to go, and the Haynes manual I've got is proving to be one of the worst I've bought - it didn't even tell me where the CDI box is located (I've found it now). Can anyone tell me where this wire connects please?

Connects to a female in the headlight shell.

Thank you - much appreciated. It looks like someone has been messing with the wiring, as I just found a coil wire underneath the tank that was also disconnected.

If you 're not familiar...Yamaha made the sorting out of wiring pretty straight forward simply matching color to color. So for your kill switch, if it is black w/white stripe then that's what you need to look for in the headlight shell. Look closely at your wiring and maybe even clean it off to see true color and if striped. Use good light too for the same reason. If wiring has been butchered then all bets are off but DEET on this site can make you an all new one.

If you think the kill switch is an issue with no spark just disconnect it. But if you really want to bypass things just find the "think its orange from the box" & go straight to the coil. Found a pic, so orange it is straight to whatever goes into the coil, might be black or orange but only one wire in. Then leave the black-white but hook the straight black into the look black, which finds its way to earth likely with the coil mount. If still no spark then--bugger. Start testing & might be why it was parked up. Bit of fun & excitement getting something running that's been silent for that long. Video would be great sometime if poss please.

no spark when I got mine
sprayed those 3 way connectors for mag, CD, coil with a contact cleaner and since then spark!
 

Thanks. I couldn't see a black with white tracer in the headlamp bowl last night, but found two empty plain blacks and stuck it one of those. I'll disconnect it for the time being. So far the mag's two ignition coils and the trigger coil (pulser) measure up okay with a meter, but I'm getting infinity resistance on the coil's HT side. I'll check it again later in case I just wasn't making good contact with the conductor in the HT lead, but hopefully that's the problem, in which case it's any easy, cheap fix. However, I'm getting odd readings through the ignition switch so I need to strip and clean that pronto.

Should be a single, black/white wire with a female bullet connector coming out of the main harness in the headlight bucket - a couple of photos of mine are attached.

If your wiring has been jiggered with and this wire is "missing", then you might have to strip back some of the insulation, to see where it "re-appears", then crimp a new wire on at this point.

  

Don't plug black-white into any loom black or it'll never spark as black is earth & black-white is ignition kill.
HT coil will have a high reading from small wire to the big wire to the plug. So need your meter on a high reading. Well, i'm thinking an analogue meter. I'm not up on these new fangled digital stuff.

Hint:  The ignition switch is not required for spark.  Just leave the black/white disconnected.  All ignition switch does in terms of ignition is ground the black/white to kill the spark