Think I might have killed it already

Hey guys check the YouTube link.
I'm turning the motor over with my fingers.
The motor hasn't even gone thru two tanks yet.
It's a ktm 50 replica motor looks the same as another type in the swap shop section but it's just a Chinese copy if it.

Not really sure how I'm going to go about this..
A new top end is $135 or another motor is $400.

http://www.youtube.com/watch?v=_1jLV8wkoPw&feature=youtube_gdata_player

I'd fitted the motor last weekend and its had roughly 2hrs run time.

I just had a look at the piston thru the exhaust port and can see a fairly evident score roughly 1/4" below the single ring. I'm not sure how or what's happened but I ended up hooking my drill up to the crankshaft and spun the motor a few times and the compression has come back like before...

I got the motor from my vendor on the cheap though they can also be bought from kdf motors for $400 in Sydney australia right near where I live
Spare parts are easy to come by to which is a bonus.
The motors at kdf are 9hp but I'm unsure of what mine would be even if they do look the same. In saying that there a cracker of a motor.

I think what the problem was when I tried to kick start it I was just turning the clutch shoe assembly but not the crank. I later found the shoes were spinning on the crank so that bit of resistance I was getting was from the metal on metal of the taper join crank to clutch.

I think this may have happened from taking the clutch apart so many times trying to get it exactly the way I want it though perhaps I didn't seat the clutch on the taper properly.

The fix was to take the clutch off again and emry the crank shaft taper and emry the inner of the clutch shoe assembly. Cleaned it up with brake cleaner and slid the assembly back on.
Tightened the nut very tight then lightly tapped with a small rubber mallet on to the cltch assembly pushing it onto the taper giving me roughly 12 to 1pm of a turn... And repeated.
So far it's holding up nicely and the bike doesnt feel like its lacking power anywhere.
The reason I tapped it on there was I slightly scored the inner taper of the cultch assembly compromising the total surface area of the taper join.

If it were to happen again I may have to emry both up again and heat the clutch assembly tappered hole then slide it on red hot tapping it in and tightening but I don't think I'll need to go that far hopefully I don't get proved wrong.

Lesson learnt was to fit the clutch assembly onto a clean shaft and torque/tighten it down properly. Its supposed to be like 20 ft/lb or something but I just do it as tight as I feel comfortable with. Also a major is don't be impatient let the locktite dry.

I'd say I tightened the nut up when I connected the drill hence when I tried kick starting I actually had compression (from my prev. Post)

I see that the crank shaft is a higher grade metal than the clutch assembly which was smart as if I were to let this get worse I could of just replaced the clutch assembly due to the hole being flogged and slid it onto the untarnished crank shaft. Atleast I know know how to avoid this pita of a problem I caused myself.