OK, so we can rule out the simple stuff.

As for the main/starter relay, you can test it if you have access to a multimeter. You will need to remove it from the bike, make sure the fuses are still intact and then first test the resistance of the relay's coil by connecting the multimeter across the red/white and blue/white wire's terminals. It should have a resistance of between 4.18 and 4.62 ohms.

Next test the continuity between the terminal that goes to the starter and the one the feeds from the battery; there should be no continuity (infinite resistance). Whilst the multimeter is still hooked up apply +12V to the red/white wire terminal and the negative to the blue white wire. The relay should click (latched) and there should now be full continuity on the multimeter display (0 ohms).

If any of the above is out of spec or does not give the desired result, then the relay will need replacing. If the relay passes the tests, then further investigation of the connectors and wiring should be the next port of call.

As for the 'spare' earth, I'm not sure. It might be normal? I'll have a look at mine and see what it looks like as I can't recall off-hand.

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