New to the forum here. I recently purchased a 2007 WR450F which had been sitting for possibly 2.5-3 years aside from the occasional start. Previous owner told me the only work it needed was carb cleaning and fluid changes along with a water pump/ oil pump gasket change. I did the aforementioned work, only to find that once it idled for a few minutes, which it did well, I blew the valve cover gasket. No tubes are visibly pinched. I searched the forum for relevant information on the topic and didn't find too much. Any ideas on diagnosing the cause for pressure to build in the valve cover? My next step will be to see if any of the vent tubes are clogged by running air through them and ensuring that they are routed properly. Other than that, I am at a loss.