Lots of possibilities here, but by your description of not needing choke when cold it sure sounds like you have an over-rich condition either due to too rich carb jetting or some other carb problem. Another possibility is a restricted air filter, is it stock? The stock filter is a foam sleeve and normally works fine, but check that whatever is on there is not modified with some really restrictive material or a super small aftermarket filter.
Does the bike rev OK above 6500 in neutral at 1/3 to 1/2 throttle? If so the slow jet and slide needle are probably in the ballpark. But if it craps out at 1/2 throttle and above when under load then that points to the main jet too big or possibly the air passage to the emulsion tube or the small side holes in the emulsion tube are plugged. I'd be suspicious of the Chinese carb. Try to find a buddy with a CB/CL/SL 100 or 125 and swap to a stock carb as a test.
Along with being too rich there could also be an ignition problem causing weak spark. Spark problems usually show up at higher rpm/heavy loads. Check points gap and timing, also spark plug obviously. And this bike absolutely needs to have a good fully charged battery to run right. Key off you should see at least 6.5 volts across the battery terminals which should rise to over 7.5 with headlight off and revving to 5K.
People often do bad compression tests by failing to test a hot engine, failing to hold the throttle wide open when testing, and MOST COMMON - using the wrong test gauge setup. Especially on small displacement engines you need a gauge with the check valve directly at the spark plug end of the gauge or gauge hose. If you try to use a gauge with a longish hose with the check valve at the gauge end of the hose rather than the engine end, then you are effectively increasing the volume of the combustion chamber by the volume of the hose. So that lowers the compression ratio, just the opposite of milling a head to increase compression ratio. In any case that engine will still run very well with 100 psi compression so don't tear it down trying to fix the bad running problem just yet. But do check for adequate valve clearance. Hope this helps.
-Bill
