Just been to look at a 2007 290 Sherco. The bike is in great condition but there is no sign of any reference to what size the engine is? I havnt rode a modern trials bike in a while so ive got nothing to refrence what sort of power it should have. Ive only got the guys word and he doesnt seem to sure. Is there any way of telling from any sort of marking on the barrel or casing wheather its a 290 or a 250?

There are a lot of 290's in comparison to the 250's though the difference in power between the 2 bikes is quite appreciable. Take someone to try it who rides one or the other they will know immediately. Both are good. The 07's are the first ones to have no cross brace on the bars.

Check the frame / engine numbers. VNBS129TR6 is the start of a VIN for a 2.9 Trials built in 2006. Note the year referenced is when the bike was built not what model year the bike is so a 2007 Model could have a frame number as indicated.