My sherco 125 2007 won't start without choke even when slitly hot when it does start it revs very hard and fast then after the choke is turned off it slowly dies or if I rev it, it it revs very fast the just slowly dies so never really ticks over.

Any advise would be great thanks

Well it sounds like an air leak but you need to start at the top

1. Fuel delivery

2. Plugged pilot jet (possible water in carb)

3. Intake leaks, cracked intake manifold, failed gasket surface etc

4. Broken reed

5. Crank seal leak, loss of primary compression = lean condition from lack of signal strength

I have to a agree with 0007 because it does sound , by the desciption , that it is running weak . Start with the carb. Strip it down and clean THOROUGHLY . I had a similar problem and that was the problem and it took an air line to clear it !!

Phil