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[Rattlebattle]

It depends how many amps the battery can provide in a short burst (cranking amps), doesn't it? 12 volts at a decent amperage will shove out sufficient watts to crank the motor won't it? It's not just about voltage.

[Richy2spanners]

Thanks Guys, after an afternoon in the shed, bike is still not playing cricket. All fuses are good. Can't see any loose connections. The battery is a newish posh one from our host. I have a good spark. However when I used to turn on ignition I used to hear a little wine until the engine light went off. Is this the fuel pump working? I no longer hear this. I do hear a click from fuse box when I turn the ignition on and a second later another click. I am assuming a relay opening and closing? At the moment I am thinking fuel pump.

[Revband]

Sound as if Tim is probably on the money then, Papasmurf a 12v motorcycle battery will not give out over 13 volts.

[papasmurf]

Revband, a "12" volt battery is actually 13.2 volts. (I am NOT going to get into a long argument about it as the subject has been done to death many times on the forum.)
http://www.yuasabatteries.com/pdfs/TechManual_2014.pdf
To understand the process of
chemical to electrical energy conversion, let’s take a look inside a
battery. The battery case is divided in sections called cells with a 12-
volt battery having six cells that produce 2.2 volts each (depending
on battery type) for a total of 13.2 volts. A 6-volt battery has only
three cells with a total voltage of just over 6 volts.

[Tim NZ]

The old 'Lucas' 12v charging system was based on a nominal system voltage of 13.4v...


Anything under 12.8v was 'flat'

[Revband]

Ah yes Papa, and further down on page 13 of you referred article, "a fully charged conventional battery will have a voltage reading of 12.6 volts slightly higher for an AGM battery" must try harder.

[papasmurf]

I am NOT getting into an argument about it. As the subject has been done to death.
Electronic Fuel Injection and electronic ignition won't work properly unless the batter is in tip top condition and a full charge. I am NOT going all over the subject again.

[Revband]

I agree re the ignition and fuel injection, but if you state something as fact it is best to have your facts right.

[Jack the Lad]

To get back to the OP. This sounds like a problem with one of the relays. Mine had this problem and it turned out to be a bad connection rather than a faulty relay. When the ignition is turned on it triggers the relay which is an electronic switch that turns the fuel pump on - which is the whirring you normally hear as itpressurises. Trace the wires to the relays and check there is a current getting there. If there is swap the to identical ones over and see if it whirrs when you turn the ignition on, if so it probably means a faulty relay, but it is more likely a faulty connection.
Hope that helps. Jack

[Richy2spanners]

Jack the Lad, thanks. I will try the relay swap trick tomorrow.