675 Stalling On Throttle Close

It could well be just a throttle balance issue.
If your bike is still running the standard fuel map, it’ll be tuned to run lean at idle for emissions which will exacerbate the problem.
Do you know if a balance has been done recently? How are your mechanical skills?
It’s an easy enough job if you fancy doing it yourself but you will need to get set up with Tuneecu or some vacuum gauges

 

I had very similar symptoms (Speed Triple 2010) when I forgot to plug in one of the sensors to the airbox after servicing it.

Handling was rough at low revs and very snatchy when accelerating and engine would die when the throttle closed

Look under the tank and check any sensor connections are tight and no wires have rubbed through

 

If you suspect it may be some stale fuel/water in the system, you could run a decent dose of RedX
This would reduce and Ethnol induced water in the fuel rails and remove any glazing from evaporating fuel
Also Avery 3rd or 4th tank run premium unleaded

 

Good luck

Also, open the air box and check a rodent hasn't made it home and blocking the air passages, although that would make it run bad at any speed

 

Agree on the fuel advise, I tend to run race bike on Premium fuel, not because I think there is any massive power gain, more because it does not 'go off' so quick when stood for weeks/months between race meetings.

 

I usually put a cap full or two of RedX in the tank when it is full, just keeps everything shiny and clean.
Started my Speed Triple up after 6 weeks in the garage and she ran smooth as could be

 

Did you fix this issue?