Fe450 engine stuck?

Hello. I just got my first husa like a month ago. It was running fine, expect little noise at the idle rpm. Didnt wonder about it too much. Then the bike got engine stuck while driving with full throttle. Got it home and opened the clutch side. The timing chain was loose.

Got the chain replaced recently and bike was working fine. Then same happened again. Engine stuck from the full throttle. Opened it again and everything seems to be okay and i got the engine turning by turning it backwards a little bit.

The problem now is it gets stuck time to time and starts to spin again when turned backwards, but cant get it to run. When i try to kick it, it feels like sticky.
Also noticed the balancer is the one that gets stuck. If i get the piston down and try to turn balancer, it will get stuck at some point and start to spin again when turned enough backwards. Anyone have any idea whats broken? I have youtube link to the video about the problem, if that helps.

Would like to know what parts to get before tearing it completely down.

https://m.youtube.com/shorts/vnBqmoGQ8IQ?feature=share

I wouldnt say its connection rod.

In the video clutch wasnt connected so i wasnt even turning crankshaft? So its not rod? I tried to feel if the bearings are any loose but didnt feel anything. It also spins ok till some point it just wouldnt move.

Any idea where that klok klok sound comes from?

Engine didnt just directly get locked, it was stalling and i hitted lower gear to get it run and then it got stuck. Gears work very good tho.

The chain didnt snap or anything, it was just loose. I worked fine with it, but i decided to change it anyways because the tensioner was at the max.

And it worked fine after as i said. Cylinder has pressure etc. So i bet my valves are also good. Blade isnt either hitting the sprague and the problem stays even if i take the sprague off. What kind of system the balancer has inside of the crankcase? Is there any stuff that can be dropped down and that locks the axle eventually?

Here i have better video of the problem. Sometime it spins easily and sometime its tight, spins with wrench tho. And im not spinning it that much so no, its not trying to open valves. Shouldnt this spin freely? So can i guess the bearing is blown or so?

(H) ttps://youtube.com/shorts/daUdaUY81GI?feature=share

Okay i took it apart. As i guess, i have some broken bearings. Now the problem is i dont know what bearings i need. Would be nice if i could get those from some local store so i dont have to wait for the shipping.

So i found the main bearing. Its the same as ktm's etc use. Can i just left balancer on the table and put it back together?

So i got the bearing and put the engine back together without balancer.

Now the issue is i cant get it to run. E-start has been always bad, but it spins the engine better than the kickstarter??

If i try to kickstart it, its veryvery stiff so its impossible to get enough speed to make it run. Same thing even if i take the plug out.
Whats the problem?? Auto decompressor looks fine so its not about it.

Engine spins ok with wrench. Timing etc is right.

The problem is finally solved. My cases were put together too tight so the crank didnt spin easily enough. Its kinda stupid system there is no gasket between the cases.

Had also problems with the sprague, it just kept slipping and slipping so i took it apart and did the tricks with the spring. Found new spring from volvo v70s transmission seals. There is now double springs and its working fine.