I'm going to stick with my original thoughts on you have more of a carb issue than a worn engine issue. I'm not saying you couldn't use a rebuild, but you should be able to get it to start and run better..... I'd put money on if you do rebuild it, you still will have problems.
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