So I got the scope and peak in the cylinders...

First off, both spark plugs mostly black with just a touch of brown. That was a wide open run with cool temps putside..... Like I said, this bike runs rich.

Top cylinder looks great, only a minor wear patch just above the exhaust port. The rest of the walls you can still clearly see the cross hatch marks. Compression test shows 130-132, that was wet as I noticed a little fuel drops running down the wall.

Bottom cylinder doesn't look as nice. Has a bigger wear mark above the exhaust port and some minor wear above some of the intake ports. The exh port bridge looks as it may have seen some damage, the edges look a little messed up. And it seems like there may be a mark on the power valve. The compression on this cylinder was 120 dry and 130 wet.

So, do I keep running this thing? It doesn't make any weird noises and seems to run fine... Why the hell did this thing seize up????/

Steve
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MC21
04 NSR50R
93 CBR F2
98 CBR F3 track bike
95 VFR750
89 FL400R Pilot
90 FZR 4/600