Good day to the community here. I would like to introduce myself briefly. I am new here in the forum, I own two 50cc scooters (Aprilia SR 50 AC and a REX RS 450), and I don’t like to “demotivate” but now I can’t really go on. My REX 450 has been mucking for a long time, (starts badly, bad gas adoption) so I thought, after all these years a new cylinder kit comes on it. (50cc standard) Penible according to Naraku instructions I then have the 101st Octane cylinder kit + Naraku head without SLS. I changed with: – new carburettor with 85/35 nozzle – new insulator with O-ring – air filter incl. box – valves set (0.10/0.10) no mechanic blockings ect. he also jumped on, ran him 2x 15 min., when giving gas some black smoke came out of the exhaust. Well, I thought because I had oiled the treads of the cylinder before I thought about it again. Engine stopped waiting for 1 hour each The next day I wanted to go into detail with the carburetor. Now the scooter doesn’t start any more. Spark plug looked at, black and damp. I don’t know any more … The only thing I noticed when checking the components that the insulator doesn’t match 100% with the hole opening of the inlet on the head. Since I used the old standing bolts I can exchange them again, but whether that’s the reason ??? without sucking the hand laid before the inlet while kicking, this sucks very neatly. I need help from the professionals please !!! Did I miss something ? THANK YOU 🙁