Red/white wire brings ignition power when the key is turned on and is fused by the Ignition fuse, and inside the start relay, is connected to one side of the relay coil wire. Blue/white wire I am going to call a communication wire although that may not be technically correct. It is connected to the other side of the relay coil wire, then on to numerous things, ABS ECU, Fuel Pump Relay, ECU, Kill switch, and the Start Switch.
The larger gauge Red/blue goes to the ABS pump on Gen2. The positive battery post has a bus strap with a spade connector to the feed side of the 30 amp fuse, and on the inboard side, the fuse is bussed to two spades... thus these two are powered at all times as long as the fuse is OK. There is a holder for a spare fuse on the left (rearward) side of the start relay. Note, there is also a relay at the ABS pump to activate it, i.e., the ABS pump is not powered until activated by that relay (entirely separate subject). The start relay is just a battery feed access/fuse point for the ABS pump, but generically could be used to power other things on other bikes, as this relay design has widespread applications.
Assuming all systems are go with side stand, neutral, kill switch, the Red/white has power with ignition on, and sends power through the start relay coil, out the other side to the Blue/white, fuel pump runs via its relay, then shuts down when fuel rail pressure reached. When you hit the start button, you are essentially providing a ground via the Start Switch so the coil will be energized (goes click) to make the "big switch" work to send big power to the starter (pics to follow).
Partially cutaway view from the inboard side, the fine gold wires are the coil of course.
Coil removed exposing the large copper contacts, bridged by a copper button being pushed against them by a black spring. Note the steel stud inside the coil, it also has a stronger spring which keeps that button pushed down until the coil is energized, then the steel stud is pulled up electromagnetically, black spring pushes up on the copper button bridging the copper contacts. One copper contact is positive battery feed from the cable, the other is the starter cable. Starter is grounded to the engine to complete the ground side of the starter motor. In subsequent pics, I have drilled out the rivetted ends of the battery cable studs and flipped the (now bent) copper contacts over.
This shows the bus strap on the right, the positive battery feed, which is a terminal to the fuse, power flows through the fuse, then connected to a teminal bus to the two far contacts (ABS feed).
So that's basically the relay construction. Now, why did it fail? As I carefully removed the coil, the first inch or two of the coil wire was brittle and had cracked/broken, thus no continuity in the coil. Years of use perhaps hardened the wire there, but that is pure speculation on my part. It does have 141k kms. (~87k miles) and if you think about how many times the Start button was pushed..... pick a number... 5 or 6 times a day during a 300 mile riding day (bio breaks, lunch, fuel stop) would be 300 times? Probably a bit low......
However, in looking at the big copper contacts and that copper button, I wouldn't say the "blackness" was terribly terrible, did not appear overly pitted like I've seen some contacts burned. Just my opinion, but perhaps as prevention, just replace it when you get up there in mileage. 80k seems like a good number to me, and cheap insurance. Remember, the OEM is expensive, generic ones can be had for $10. But, I'll leave all that up to you. I am putting a very low mileage OEM relay on this bike just because I got it cheap too and want the new owner to have OEM. As far as the generic, well I have been known to tear brand new stuff apart too.
