So one side of the relay is routed to the Y/G wire coming out of the starer button and the other to some ground point? And you're seeing 3.5V on the terminals of the relay even when you're not pushing the button? What ground point are you using?
No Im seeing .35v. But thats not when it is faulting. Putting the switch back in and the relay out the bike is back to normal. Ground is to the battery.
My think the starter line is the cause. So when I get time I will power the relay from the brake light circuit. Need to pull the tail off and work out which wire it is. This will mean I have to pull the brake on when I start it but thats what I do anyway.