HELP!! rev problems

[roders89]

My bike is a 125 4stroke when is idling for about 10 15 mins and warm if I rev it up to 7 thou rpm and let go of the throttle it drops to 3thou rpm stays there for 1 min then slowly drops to idling speed of 1500 rpm.
Has anyone had this problem and hows it fixed?? My bike has a cv carb iv striped and checked it and all seems ok
I cant get the bike throw m.o.t because they keep saying sticky throttle cable but is not iv new one installed to be sure

[roders89]

Iv tryed all that and nothing realy has me stumped

[roders89]

My carb has only one screw on it its mikuni bs26 doesnt matter wat way I screw it does nothing???

[roders89]

[roders89]

S3fella you were right bikes purring like a kitten thank you this prob really toke the piss