Erratic rev counter

[blainec]

firstly Happy New Year to all fellow airheads , I hope 2014 is a wonderful year with many hours in the saddle.

I need some help from the gurus on the forum . My bike is running like a dream but suddenly if i get to around 135 to 140 km/h the revs are at roughly 4500 rpm , if I accelerate a little more to 5000 rpm the rev counter is all over the show both up and down , but the engine is still running smoothly and the speed remains constent. If I accelerate a little  more it settles down, the same if I deccelerate .

I thought maybe the clutch is slipping so I adjusted the clutch cable with a 4mm play as it says in the manual. This did not help.

Obviously this is quite disturbing , I am sure it is not an engine problem, could it be the pick up , or is the guage itself buggered?

Any advice would be great.

 

[Welsh]

 

[blainec]

 

[Welsh]

 

[Fudmucker]

 

[blainec]

 

[gser]

 

[Chairman Meow]

 

[blainec]

 

[Leo]

 

[gser]

 

[blainec]

 

[LappiesLabuschagne]