So here's some interesting info that I haven't seen full explained in the Haynes manual, the Yamaha manual or any of the online guides...
I bet there's loads of Yamahas out there on the road with mis-adjusted EXUP valves because of this...
The EXUP control system has *two* reference points - I'll call them start and idle:
- the start position is where the valve should be when the engine is being started up.
- the idle position is where the valve should be when the engine is idling.
The start position - fork directly over hole.
The idle position - valve rotated (clockwise / opened) 30 degrees.
Here's the tricky bit - the valve should be adjusted to the start position but the EXUP control system only returns the valve to the start position when the ignition is switched on and the engine is not running.
And when the ignition is switched on the control system 'self-test' only returns the valve to the start position - it doesn't do any other full-deflection type of test movement. So if the valve is already in the start position it does nothing at all. It's not much of a self test really.
So, if you stop the engine by use of the run/kill switch or stall the engine the control system will zero the valve to the start position.
But if you have the engine running and switch the ignition off the control system is powered down immediately and the valve is left wherever it was (probably in the idle position). This is what my mechanic had done - the control system left the valve in the IDLE position and he'd then gone and adjusted the valve to the START position with the fork over the hole - 30 degrees retarded.
So my valve probably started off pretty well adjusted and the guy I paid to fix it adjusted it to 30 degrees more closed than it should be. Fortunately, it was so far retarded that when the control system tried to move it to the start position the valve actually hit its end-stop and wouldn't go far enough and the control system threw the 7k signal, other wise I'd have never known. Yeah, that's why I prefer to do stuff myself...
So, basically, all the instructions I've seen are incomplete or at least unclear - it is essential to have the ignition on for a few seconds without the engine running so the control system can set the valve to the start positon before you do the adjustment.
unfazed - you were right - gotta use the kill switch, not the ignition. When I see 'hit the kill switch' I tend to just switch the ignition off automatically but in this case it's gotta be the kill switch!