hi all problem with crf just had full service and valves checked bike starts nice idles for around 2 minutes then cuts out on its own with a strange clank noise wich sounds like its coming from cam chain side sounds like top end sometimes when you rev it it cuts out with this noise aswell im just after advice before taking to a garrage and getting ripped off and charged a fortune already happened once and just not got the money please help lads all best

Are you able to restart it immediately or very shortly after it stops?

My guess is the reason for stopping and the clank are unrelated. The stopping is probably fuel or possibly ignition related.

The clank is probably cam chain tensioner / guide related. It is almost certainly a case of strip, examine parts and replace as necessary.

Hi yes mate starts straight up after was told the noise could be decompression lever inside come loose or cam chain tensioner if so are these expensive jobs to have done just dont want to get taken for a mug by garrage as im not to clued up on the matter thanks mate

That noise is definitely the decompressor, the 250 and 450 honda do it aswell so don't worry about it. If you lift the cam cover off and look at the decompressor mechanism on the end of the cam and rotate the engine slowly by hand you'll see how it works and why it makes the noise you hear.

To change the cam chain tensioner is easy, if you need to that is. Remove the cam cover and make sure the chain doesn't move on the sprocket when you remove the tensioner, just simply put the new one in place in a reverse procedure.

They really are quite a bullet proof little engine if kept maintained correctly.