Hi, I have a 2001 yamaha yzf 600. I took the carbs off to blow them out and put new plugs in. When I put them back on and took the bike for a test drive, it ran fine for about 2 minutes, then started running rough and had a noticeable loss of power. I wasn't able to work on it fuurther for a few weeks, but now I pulled the spark plugs, and 2 seem normal, one looked corroded, and one looks white. Any ideas what the problem might be would be greatly appreciated. thanks, Jim