You are going to give me a stroke. Start over.
Pull off the cylinder head kit, and inspect everything. The rings should all move free just like when you bought the kit. Look at the piston. this page will help.
http://www.smellofdeath.com/lloydy/piston_diag_guide.htmIf everything is good then put it back together.
The EGR pieces you took off/on/whatever will not affect anything as far as how the bike runs. If you have broken or missing parts you simply have to block it off AT THE CYLINDER HEAD or OUTLET side of the stainless pipe. String, and bent rubber hoses don't work. Use a piece of a soda can. Just cut it to fit with a pair of scissors.
Answer these questions but don't ask or say anything else... How long ago did you install the 80cc kit?
Did you change the jets in the Carb? How long did you ride with the broken ERG system? Which piston in the chart looks most like yours?