Shouldnt take any time at all to see the effects of what you just added. It goes thru the hole & bounces off a small L shaped baffle & its in the crankcase.

I have a 3 oz bottle that came with the weedeater. Its a 4 stroke.
It makes a clear difference in the oil level in the window, but Ive not measure the amount of oil needed to get from low to full.

I thought about a half qt. also, but wasn't sure. I like the 3 oz idea. Also didn't know how much it had to go thru to get to the bottom. The reason I ask is that I had to suck some oil back out once, pain!

That sounds like a capital idea, but if you will look at my bike, it's a trike! I found a 60cc syringe and some tubing at work. It isn't hard once you get the hang of it.

I swear, some day Im gonna remember to cut a couple of grooves in the first 1/2" or so of the threads on the drain plug. If I do get too much in, I can back it out till the oil drains slowly out the grooves & not worry about it popping all the way out & draining the crankcase completely.
If ya do that, make sure you clean those threads up, best to put a nut on & back it off & chase the threads, or use a die, or a thread file,,wouldnt want to screw up the threads on the engine. Or stick metal bits in..

Routy wrote on 09/01/09 at 21:49:08:

It's not really a problem unless you have one.  It may cause weak seals to pop or leak.  But that in conjunction with another problem.  Internally, may cause foaming, which leads to bubbles in the oil stream, which leads to advanced wear in the journals and bearings.
A little too much oil is better than no oil.

Here's a pic of the "trike" except it is not a true 3 wheeler. The back wheel is still on. I chose this way because I am 68 and this is my first bike. At my age I do not want to hit the ground!

If you right click and vue imagine it comes out smaller