Same thing happened to mine some time ago. Turned out to be the TPS(Throttle Position Sensor)

Drove me nuts! It didn't do it all the time, and didn't throw a code.

There is an onboard code reader on your bike. To read it just hold your speedo reset button in, then turn on the ignition switch with the button depressed. There are 4 or five selections from there you can scroll thru with the button. . "P", the first selection, is where you're likley to find it if it's there. It's easier to tell you just play with it, than it is to explain the whole process. However, if you "Search" "Reading codes" here on the Forums, you'll find good info on that.

Even "Google" will give you some info.

Hope this helps

Best wishes....Tim(HT)

 

OK so for those interested,

No codes on the bike, I'm going to pull the fuel pak, and see if it happens again.
If it doesn't I'll put it down to that and think about getting a SERT. I had one on my Sporty and it ran like a beast!