So my buddy’s bike the engine is a super tight fit so he’s unable to put a air filter on it (I’ve told him he should buy a shorter/angled intake) and we think he sucked in a pebble or something, I wasn’t there but he says he was riding and all of a sudden the top end started making a squealing noise, he shut it off for a few minutes then started it back up it was really hard to start and smoked a bunch when it did start and had no power it would only go like 5 km/h and when he’d pull in the clutch the engine would die as if you hit the kill switch also had low compression. So we took off the top end and there was a little chip in the piston and a pretty deep gouge/scratch from the top to the bottom of the cylinder. We put a different piston and cylinder/head on it, not a brand new one it came off a parts bike that had good compression low hours (both Zeda engines) and with the other top end it still has low compression. Any ideas on what the issue is? I thought maybe the clutch wasn’t working right sense when it was running with the original top end after the squealing when we think it sucked in a rock it was dying when he pulled the clutch in as if he hit the kill switch (before swapping I took it for a ride and yeah it barely had enough power to pull my weight and if I pulled the clutch it died instantly) so I released the clutch cable from the clutch arm so the clutch should be fully disengaged but it didn’t make a difference we also tried adjusting the flower nut a full turn each way in small increments and testing to see if it made a difference but it did not so I don’t think the clutch is the issue. I’ve changed a top end before on these engines and on dirt bikes/atv’s I believe I did everything right and I don’t see where I could’ve went wrong. Anyone have any ideas?