I've been ridding a sport bike for a year now, since I've been ridding I've noticed that during sex the amount of sperm that comes out is almost none?

Bicycle Sperm Count. There are numerous conditions reported by bicycle riders that are associated with compression of the nerves and associated structures. These have had some popular but inappropriate names to mention here. Probably the first issue to address is a properly fitted seat with appropriate cut outs to accomodate the male genitalia. Read: http://www.Medicinenet.Com/script/main/art.Asp?Articlekey=84072.
Sport bike. If you ride more than three hours per week, in addition to effective nerves which might control ejaculation, you compress venous drainage from the scrotum increasing testicular temperature [just like a varicocele] which can adversely effect both sperm production and quality.