also realize that when you blip the throttle, you are making power when the throttle is open, but when closed, and the engine is coasting down, there is significant vacume generated in the cylinder at points of the combustion cycle. if there is oil anywhere in the system (under the upper ring, or accumulated on the valves, or in the breather... this will give you puffs of smoke. Normally you don't see it because you are on the bike, and normally any excess oil will burn off during your first coast down to a stop sign when the bike is warm... but you can see puffs giving it the revs on the stand.
understand that this can also be water vapor from moisture in the header if the bike isn't up to temp. or small amounts of water in the fuel giving you puffs of steam (rather then smoke).
you can put your hand in it, far enough away that you don't get burned, and then smell it. tells you a bunch of things... if you do have oil leak by you will not only smell it, you will feel it, your hand will feel oily. if it's water, you won't smell the oil, it will smell like exhaust, but if you have a coolent leak into the combustion area, you will smell antifreeze or burnt antifreeze...
Need to know how to install your Rifleman's 1/5th throttle insert? click me
For more info on a sticky grip (not enough cable slack) click me
And another amazing install write up click this
lol, once you go 1/5th... you NEVER go back