High idel RPM, rough ride when riding slow
I have a 2008 K1200s, 38000km. Serviced every 10,000km, The last service at 30,000km I had the plugs changed and valve clearance checked etc.
On my work commute I spend about 20 min on the road doing ~120kmph (75mph), after 20min and I slow down at an intersection and ride slowly through traffic. When riding with little or no throttle the revs will be much higher than usual, when running normal the idle is at about 1000RPM, but when this issue occurs the idle goes up to as high as 2500PRM. This cause the bike to not engine break effectively and to speed up. It makes slow riding almost impossible without riding the clutch. It doesn't stay consistent at 2500RPM either, it will suddenly drop back to 1000RPM causing the bike to engine break throwing me forward, after I turn on the throttle to drive on it returns to high revs.
The strange thing is that if I give it some power, say bring it up to 4000RPM, I wouldn't have issues and it appears to run ok unless I try to slow down. Added to that if I turn off the ignition, while driving and just coast for 2 seconds, and turn it back on again the problem goes away for another 20min or so. I can slow ride and bike runs as normal. It also doesn't happen when the bike is cold. It only seems to happen if I have been riding at constant high speed for about 15min and then slow down. It doesn't happen if I am constantly slowing down and stopping at junctions or in city driving.
I had the TPS changed and the plugs have been replaced with new plugs and was fully serviced about a month ago. The mechanic hasn't been able to find the problem and there are no error codes coming up.
Any advice or info will be appreciated as I cant really ride it as its too dangerous to be in heavy traffic and it is unpredictable.