Thanks for your input guys but the long soak in paraffin and an aggressive blow out with the air line and she is running top notch!!!
Hardly believeable but anyone else with this problem, Please take note as the carb has been blew out twice to no avail..
Thanks again, Stevie.

Hi & Thanks for the suggestion but the power valve is functioning and setup correctly.. I have had the carb sat in carb cleaner for the last 2 days and I'm going to blow everything out with the airline. Inlet rubber is ok, reeds ok, If this clean out doesnt sort it, Look out on ebay as I am complete...

Forgot to mention, Airbox is drilled, Snorkel from airbox removed, moto air filter, 150 main / 45 pilot jet and a full dep pipe.

I have recently purchased a 1994 crm250 mark 3 and have a problem regarding correct running. The bike runs fine at low revs i.e ticks over and revs to about half throttle (Start of Power band). The bike will not run at high end revs and just coughs and splutters. I have tryed removing the airfilter ...

Just popped by to say "hi" to everyone... Im from the Scottish Borders & I've just bought myself a 1994 crm 250, So was overjoyed when I stumbled over this forum.. Looks like theres a wealth of info on here. Thanks for now, Steve.