Did you get your carb sorted out then?Update:
I don't think I was running the engine long enough to see the changes previously. I lowered the main jet to a 150 and see a noticeable improvement and will continue to play with them.
I think I may be too rich on the pilot and needle now because even though it runs pretty good low end and mid range, there's a noticeable power gain about mid throttle even with my 200 lbs riding it.
I'll continue to tinker with it but the thank you all for the advice to steer me in the right direction 👍
Reading your last jet settings I think you were still way too rich based on my recent experience with a larger engine.
I just freshened up my TB 114cc big bore kit with a highly ported race head, matched intake porting, large duration Z40 camshaft, high flow exhaust, UNI filter and ported inlet Mikuni VM20 carb. So it's definitely moving more air than an 88cc engine and my final jetting is much leaner.
In cold 34° F weather my VM20 ran best at a 20 pilot, 120 main jet, needle clip 2nd from bottom (one step richer than center clip position) producing a clean carmel colored plug.This was the best throttle response jetting running crisp throughput the rev range with no bog or sputtering on WOT.
Tryed a 125 main and it was a little blubbery (rich) under WOT in this cold weather and would only get worse in the summer heat.
The 114cc engine started, idled and ran very good with a 17.5 pilot but the idle air screw was only 1/4 turn out so a 20 pilot was the better choice with zero stumbles just off idle. Same with the needle jet in the center position, it ran good with an occasional low RPM transition stumble, but ran perfectly with the clip down one step richer.
I had originally guessed the 114cc VM20 jetting would be 17.5 pilot and 115 main just by math comparing engine size to my perfectly jetted Piranha 150cc VM26 engine. In truth its not far off from where I achieved optimal 114cc jetting once all said and done. 😉
A VM20 is a pretty big carb for an 88cc, and mathematically your main may end up down around 100 or slightly Larger as the carb signal will not be as strong as my bigger cc engine.
How big is your intake valve diameter and how How black or sooty looking is your spark plug now? 🤔