The choke on my 450 started playing up, where it would not go fully off.
Being the busy fella I am, I just bought a new cable.
When fitting it, I found the old cable to be intact.
The problem was just where it enters the carburettor, the cable passes through a curved piece of steel, and as I wash my ATV so much, the inside of this pipe and spring had become corroded.
A good cleaning and a liberal application of grease inside this tube restored the choke to its former glory, no new cable required.

Might be helpful to someone out there.