Ok I've now checked fuel pump, it's fine spark at plugs fuel at injectors. Took all earth wires off and cleaned checked fuses ,removed tank and checked/ cleaned all connectors but still don't start.. just turns over and then you get a bang...? Thinking the hal sensors are shot? Any help greatly appreciated.

keep your hand at least 12 inches from the throttle when you hit the start button i.e don't twist the throttle at all as fuel injection will just flood the motor resulting in a loud exhaust backfire..not like a carby bike where you twist the throttle to get fuel into the donk to start it..been there done that

As you get spark, I doubt that there is a problem with the hall sensor. (hope that you didn't reverse the connections for the coils ).
First, check the connector at the FI computer, then you should check the mass airflow sensor (in the air filter canister).
All values for checking the MAF can be found Here

Cheers, I haven't reversed anything on the coils all I have done is removed the HT leads and cleaned then then put back... Will do airflow tonight. Do me FI Computer a couple of times today but no change
Checked hal sensors open and closed and both 4.95 and 0.02 respectively. Doing my head in, one minute your out riding and the next.... ✊✊✊.

Foxxys wrote:Doing my head in, one minute your out riding and the next.... ✊✊✊.

Did you ever disconnect the anti-theft alarm and rewire the starter relay back to its original configuration? You seem to have three different threads concerning this engine's failure to stay running so its challenging to keep up with diagnosis and treatments.

I only ever disconnected the anti theft alarm, the first time I done this an alarm sounded until I put the ignition on. I then reconnected it after cleaning. I have never rewired the starter relay back to any configuration. ? Can u explain how to do this please ?

Foxxys wrote:I only ever disconnected the anti theft alarm,  the first time I done this an alarm sounded until I put the ignition on. I then reconnected it after cleaning.

If I recall correctly, one of the function of the anti theft is to ground the water temperature sensor which signal the FI computer that the engine is over heating. The result is that the fuel injection is disabled.
Are you sure that you have injection? Did you pull out the FI ramp to check if they spray correctly?

Yes I pulled it and they are spraying thank though...

Are you absolutely, positively, sure you have the plug wires on the right plugs?  You wouldn't be the first to have them crossed.

Scouts honour😁

So here is the alarm disconnected. Which wire connected to which contact of the starter relay by passes the anti theft? Just so I can rule a faulty anti theft out? http://www.motobrick.com/index.php?topic=6767.0

Might have found something.. the mass airflow resistance readings
7-5 = 94.5
7-8 = short
8-5= short

Will try and source a replacement...