seriously considering swapping my husky TE610 for my brother's WR450F. he said it has always run really rough when cold, but can't find anything about this on the forums. he's had this 2006 model since new, never touched the jetting or done any mods that might affect jetting. it runs fine once it's warmed up, but figure something doesn't sound quite right. does this just sound typical for a WR? any tips on potential problems to look out for much appreciated!