Removing the flywheel is impossible, no way to change the seals with the impact wrench to loosen it, the bolts get damaged. What can you do, burn it with a torch in hopes it loosens, but there's a risk of damaging the crankshaft bearings. Lowering the engine costs 200 euros to fix. Better to buy another one, but if it's for seals to have such issues, it's not worth it at all

I have had it since 2012, I have done thousands of km. It's a great little bike. The oil changes every 1000 km. And at some point, I changed the discs to genuine Astra discs so it wouldn't skid. A trouble-free little bike

First of all, let me clarify that I didn't use the engine for a long time (not because it broke, but because I sold it).
I had it without a flywheel cover and it didn't give me any problems for the two minutes I had it without it.
I revved it a lot and it didn't have any issues.

Positives
1. Fast for its price, it revs well and actually performs like a 100-110cc (depending on the exhaust, carburetor, and gears you use).
2. It doesn't require any special adjustments if the bases fit (not in terms of electrical issues).
3. The engine is very simple to fix.
4. The gaskets and screws are quite good, at least from what I've seen with Lifan engines, they don't leak oil unless someone who doesn't know what they're doing has tampered with them.

Negatives
1. It easily leaks oil.
2. The gearbox is very heavy and the gears don't engage easily.
3. If you adjust or replace the carburetor, it's difficult to set it up so it doesn't cause any issues, it's not like the more well-known brands (Honda, etc.) that are easy to adjust.
4. It definitely requires some modifications or adjustments (except for Chinese bikes, in my opinion).
5. I've heard that it breaks easily, but for its price, it seems reasonable.

For a maximum of 240, get it, but don't think it's for heavy use.

It is worth it and more, the powerful motor impressed me. I made the Argos-Leonidio route without any problem (about 80 km).