Hi all. Wondering if you could maybe help and give me a diagnosis. I have an old 96 yamaha virago that's done 70 odd thousand clicks. Today on my way 2 and from work I had lacking power in top range of 3rd, 4th and 5th gears. 1st and 2nd are fine through out the range but the top of 3rd and most of 4th and all of 5th..... no power with coughing and spluttering. It rides much better with the choke on. I previously had problems with a valve sticking and the bike had problems starting and it was coughing and spluttering. The valve was freed up and has been fine since. Could it be the same valve causing the problem? PLEASE HELP ME!!!