How much tranny oil to add for 2 stroke?

Some of that may be the difference between quarts and millilitres? My Honda owners manual says how much to put in and then goes on to say to use the overflow bolt to drain any excess. Can't go wrong with the overflow bolt IMHO.

Ktm manual says to fill until the weep hole leaks. Do what your manual says.

I was going by weep hole. Then I found out there was about a 200ml difference between the weep hole amount and the amount called for. So then I started measuring. I haven't noticed any difference in wear or performance. 2 stroke clutches are pretty resilient in my experience.

Go with the volume amount listed.

What bike?
Is bike level when filling?
I'm wondering if there is a special procedure for draining?

I am in the same boat. I fill my ratio rite with the ml in the Ktm book and make sure the bike is level. Then pull the check bolt and start filling but it starts to come out of the check bolt with a decent amount still left in the cup. I just kinda split the difference and haven't had a problem but I've always been curious. Ktm 250sx 2013

when changing the tranny oil make sure to drain well enough the old one out, be patient and wait to drain completely also many engines keep some small quantity at the tranny side so you have to tilt the bike to the clutch side to help get the remaining oil out.

There are essentially 2 compartments in there. The one where you pour the oil in where the clutch is and the one in the center of the cases where the transmission is. Usually there are only 1 or 2 small holes allowing oil to flow between the 2 compartments. If you pore oil in with the check screw already out it will rise to the level of the check screw and drip out before it gets a chance to actually go through to the transmission area and reach it's final level. Essentially you are getting a false reading. You need to be more patient and wait to remove the check screw.

Or save yourself the trouble and just pour in the amount printed on the cases or in your manual and don't use the check screw.

On my CR250, it would only take about half of the recommended amount of oil before it would run out of the check screw. I would have to then start the bike and let it run for a few seconds then shut it off, then remove the check screw and continue filling with the rest of the oil. And even then, I would add an extra ounce or so after I replaced the check screw just for good measures.

I go by the volume + about 8%.