What engine sound is this!? (video inside)

I just bought an aerox. Carb have no air filter. Choked-lever/nozzle is missing (just a hole in carb).

when I leave it for an hour or so or overnight in a garage the bike will not start after 5-20 minutes! ​

I try the electric start at first without throttle, I then try it multiple different ways including with/without choke, with/without throttle, but it still doesn't work. ​

the bike does make the noise when the electric start is used. THIS EXACT SCREACHING SOUND (youtube link: https://www.youtube.com/watch?v=i-6arvWq3po)​

After a while it will turn on but then cut out and turn off again straight away. SAME. ​

When using the kick start it just hurts my foot after a while because I will kick it( and correctly because I can do my friends moped) multiple times, eventually it will turn on after too long SAME. ​

 

It will most likely be down to a worn bush in the transmission case that is supposed to locate the starter bendix and take some of the load as it engages with the teeth on the variator. What it happening is that the starter motor is spinning the bendix out, but because the bush is worn out, it can't engage properly with the variator teeth, it gets pushed sideways slightly, so the gear on the bendix 'chatters' on the edge of them or doesn't engage properly at all.

I suggest that you remove the transmission case and check the edge of the variator for damaged teeth and look at the two bushes that locate the bendix (one in the transmission case, one in the crankcase). They will both probably need to be replaced to bring the bendix back into correct alignment.

 

Thanks mate! Transmission case, is it the "swing arm" case? The kick have teeth that intersect with the variator - is it the same principle from starter engine?

 

Yes, it's the case that has the kick start coming out of it.