Revving while in drive
 

Today while riding home I was going around a bend at about 50 mph and in 2nd gear. I happened to pull in the clutch and I couldn't hold the rpms at a steady point. It acted like a cylinder was misfiring or something. What is strange is that it runs fine in gear with the clutch engaged all the way through the rpm range. Also at a stop in neutral or the the clutch disengaged i can rev it through the entire rpm range.

I am pretty mechanically inclined but I can't think what could be the reason for this unless this is normal. I don't know if I've ever tried this before but I imagine I have and this hasn't happened. Does anyone have any thoughts? I know its not good for the motor to do this a lot but I just want to make sure there isn't any underlying issues.

Thank you for any input.