05 Speed Triple Cut Out Issue

Hi, fairly new to the forum and Triumph and to bikes in general, I'm after a bit of advice, I have a 2005 Speed, i bought it earlier in the year, and was told that it had a new reg/rec on the bike, as I had read that its a common issue anyway took the bike for a ride yesterday it was a bit lumpy on start up, so i took it steady locally to make sure if something wasnt right i wasnt far from home. After 5 mins the bike was fine and idling, rode for around and hour and stopped for a cuppa, jumped back on started the bike no issue this time, rode home and literally the last corner before home it started to be really lumpy on idle, pulled on the drive and turned the bike off, but the revs with the bike off were stuck at 4k and the bike sounded like it was about to drop out of idle. I have the bike on a an oxford oximiser while in the garage all the time. Please if anyone with knowledge can point me in some sort of direction to fix it i would be very grateful,

Thanks in advance

 

No sorry to confuse, i turned the engine off, but the dial was stuck at 4k, i turned the ignition back and i did the dial sweep but stopped at 4k again instead of 0

 

Yeh i gave it a tap and turned the ignition on and off a couple of times to see if it would sweep back and it didnt seem to do anything. The bike was serviced about 300 miles ago i got a full service when i got the bike, i do this with cars as even with history i like to make sure 100% that its sorted so not to have further issues, i think its strange how it will run really well for a couple of hours and then grumble, surely it wouldnt run well at all and would run like rubbish all the time?