I bought a stock wr450 two years ago that I uncorked right away. I had the AIS blocked off properly and the right jetting to match. I think that somehow when i was switching between high and low elevation jets, the cap on the vacuum line came off without me realizing and I got it jetted to run pretty well. I have been riding it for awhile without knowing this but whenever it is running there is air being sucked in the vacuum line. When I put my finger over the hole the engine dies immediately. I can only imagine that running the bike without the cap on the vacuum line is a bad thing so my question is, What do I need to do to get it to run while the vacuum line is blocked off? Do i just need to get the jetting and fuel screw dialed in? Thanks in advance!