I was riding my bike and down shifted into4th gear and then upshifted into 5th gear and the bike just stopped pulling.The bike still shift into gear while sitting still,can you help me with this problem?I can`t figure it out!

Thoughts:

Check the clutch adjustment. Check the clutch cable for binding. On some bikes, there's a jam nut around a slotted stud, which is used to adjust the clutch. Ensure the oil in the clutch sump is not friction modified, which will cause all kinds of slipping.