Ok here is the story. the sled belongs to a friend. A few weeks ago we went riding and it idled and ran good. On the way home the base gasket blew out on the clutch side "recent rebuild and nuts came loose". We pulled the jugs and replaced the gasket. No more leaks. At the same time he wanted to put on my set of triple pipes I had from my old XLT. Put them on started it up and it would not idle. It will somewhat idle for a few seconds and then drop down and die. We pulled all the carbs and cleaned the jets and blew out the carbs. Put them on and adjusted them in sync. Still the same. Checked compression and they all are 125psi. New plugs. The kicker is that it was running fine before the gasket blew. I have owned and worked on sleds for years but this one has me at a loss. Oh we even checked to see if it was leaking fuel through the vacuum hose to the fuel pump. Does anybody have any other ideas? It just acts like it's flooding.