I just got a 1979 CM400a, I cleaned the car and it doesn't seem like anything is bad. But before and after I cleaned it the bike has no low end power. The bike once warm will idol a little rough but it will stay running. When I put it into gear and hit the gas there isn't any power and it...

Just bought this bike and I got on it and it takes about 30 seconds to get up to 20mph then it takes off like crazy. Any suggestions for what the problem could be?