I modified the stock exhaust and removed the secondary butterflies. I removed the stock muffler and midpipe, and I'm just using an exhaust tip made from the midpipe, so the exhaust exit is right behind my heel and ending right before the swingarm. After doing the exhaust and butterfly removal mod my bike seems to still run rich. I expected it to be lean, as it was said removing the secondary butterflies would cause that. Any ideas as to why it would run rich after all this?