No Spark - curvy.

My 2000 curvy sv650 has been playing up for a couple of months now. Sometimes it starts first time & others it just turns over & won`t start at all. Leave it for a while, try it & it starts. Last week the Wife rang to say she was stuck at work cos it would`t start. She`d tried so much the battery was almost dead. I got there, tried it expecting nothing & it turned over once & fired up. Someone suggested it might be the immobiliser so searched this site & found how to disable the immobiliser, so that is what I have done today.
On the right hand side were 2 black wires from the Datatool spliced into the yellow/black starter relay. Cut & rejoined, tried bike & it fired up.
On the left side were 3 black wires from the Datatool. 2 spliced into the yellow/orange ignition fuse wire. Cut & rejoined, tried bike & it fired up. Job`s a good un. Left the other black wire because it was soldered into the thicker core orange ignition fuse wire and wasn`t breaking any circuits.
Put the bike back together, went to start it & guess what, it just kept turning over & wouldn`t fire up. Have now stripped it again, checked connections they are ok.
I`ve pulled a plug lead off, put a plug in it, turned it over & there`s no spark. I`m leaving it for a while now before I attack it with a hammer.
Daz

lead breaking down?

[yorkie_chris]

Possibly the ignition switch. There are 2 wires which the ECU needs to see connected with a certain resistance.

The switch can go dodgy and not make this specific connection all the time. When it fails to fire, try turn the key off and on again.

The ignition switch problem sounds good but I`ve now tried it about 20 times & still no spark. Before yesterday it would always start at some point but now since disconnecting the immobiliser there`s no spark at all. I remember trying it after cutting the starter wires and it ran & I`m sure I did the same after cutting the ignition wires.
The alarm is still working & the immobiliser is definately disconnected. Have I missed something simple & how do I test other circuits?

[yorkie_chris]

Take the connector off the ignitor box and put a multimeter to it

I`m going to borrow my Dad`s meter & test everything. Found an earlier thread with a guy who fried his ecu while playing with immobiliser.
Thanks for the advice, Daz

Electrical issues are always a pain, but you just need to be methodical.

If it was occasionally starting before, it might be worth re-wiring the immobiliser. I've not heard of anyone frying their ECU, but you could always unplug it while working on the bike, and just plug it in when you need to.

Another thing to check would be continuity between the negative coil feeds and the ECU.