vertical lines in cylinder wall

[Lopper7]

Rebuilt the top end and started the break in process.

Then the bike shut off and wouldn't start so I said f it and left it parked for about 1.5 months.

Now that I calmed down I started working on it again.

I leak down tested it and it holds 7psi for 30 min. So I thought great now wth is it.

Took the head off and see vertical lines in the cyl wall, but it's smooth, you can't catch a fingernail on it.

Are the lines a bad sign or is it normal for a forged piston?

 

[Rubbersalt]

Bad sign. Can you provide a picture?
What oil mixture and oil type are you running?

It sounds like something has come loose or it has over heated while breaking in. A leak can cause it to be lean and over heat and swell up. Wiseco is also know as seize-co due to it being prone to seizing. Proper care (explained below).
Check your bottom end rod bearing. It's possible the needling bearing came apart.
Check the piston skirt, it could have cracked or broke
Are the piston rings in upside down?

Forged pistons have to be broke in carefully. They also have to be babied for the rest of the life. Treat them like a turbo charger after braking them in and they'll last a long time. Let them warm up for 1 minute of idle and cool down for at least a minute after riding. As for the break in, everyone has their method. This is mine, it works perfectly well for all forged or cast. Low rpm and several heat cycles. Do not use synthetic oils for the break in.
Idle for 15 minutes, cool off, repeat 2 times.
Idle with 1/4 throttle blips for 15 minutes, cool off
Idle with 1/2 throttle blips, cool off.
Lightly ride with 1/4 throttle and some 3/4 blips, cool down and then let it cool off for 10-15 minutes.
Lightly ride up to 1/2 throttle and some 3/4 blips, cool down and then let it cool off for 10-15 minutes.
Ride up to 3/4 throttle and some WOT spurts, cool down and then let it cool off for 10-15 minutes.
Ride up to 3/4 throttle and some WOT spurts, cool down and then let it cool off for 10-15 minutes.
Enjoy.