I run a Menz Ultra 22-10 at about 7200RPM with 40:1 mix.

A Pro Zinger gets about 7000RPM

Bambula 22-10 was down near 5700RPM

Bambula 22-8 was about 6500RPM--maybe 6600RPM

Menz S was 6900RPM.

Get your engine speed up in the 7000RPM range on the ground.

I am blown away that your only getting 6800RPM. I am running my engine at 8000' above sea level and I can get 7200RPM up here in the thin air.

Oil makes power--to a certain extent. If you can't get those RPM out of your engine--consider a 50:1 or a 40:1 mix on the gas. Just my opinion--and not to try and start another oil war--but IMHO 100:1 isn't enough oil. Thats like a shot glass of oil in your fuel jug[X(].

40:1 is 3.2oz per gallon
50:1 is 2.56oz per gallon

I've read posts--LONG AGO--about some of the guys running 100:1 mixes and getting hot on high RPM runs or hot days. If they ran full out for any length of time--the engine was overheating. The solution was to richen the high speed needle. More fuel = more cooling; was the consensus.

B.S. all that does is ruin the transition and foul the plug.

Put some gosh-darned oil in that thing and you can tune it to run full throttle for 20 gallons straight without ever overheating.

I'm not saying oil ratio is your problem in this instance. I concur that it is the vent hole in the carb. and that blocking the airflow from turbulating around it will solve the problem.

But, your numbers do seam low to me. I'd consider changing the oil ratio and see if you get anymore power out of it. You may just be pleasantly surprised.