I have taken my yz400f to my local shop as i bought the bike as a non runner and got it for a very good price. The bike has a great spark, tons of compression. The only thing was that it had been standing for 6 months so i thought it may have just been a carb clean out job. However it was'nt, and still would'nt start. So i took it to the shop and the guy has told me it may be the valves and wants to charge me $200 just to check them. Is this the case or is he adding money on needlessly as i don't have a clue about 4 strokes.