I recently bought an 88 XT600 that wouldn't start easily or stay running, but sounded good when it did. It sat for 2 years so I figured clogged carbs. Well I cleaned them(twice actually) and made sure no plugged holes. I got it running and it ran great, full throttle and all.
I filled with gas(it was old gas in it), 93 super unleaded here in the states, went 2 miles toward home and it suddenly bogged like it was working real hard and kept popping/ backfiring. till it died, wouldn't restart. after a bit with full choke it did start but same thing and died. Recleaned carbs, made sure no air leaks(even put light silicone sealer on some things).

It then started up and ran perfect, idle smooth, let idle for a couple minutes then bog and popping again and it died. I belive it would be the cdi or coil( it didn't seem to have great spark, but the bike is new to me so I don't know how good it should be) the plug color looked a bit lean and even after kicking on full choke it was dry. That says fuel issues, but outside of some internal air leak or out of spec part it isn't a clogged jet or port. BUT the popping and bog when it gets warm says cdi. Any of you that have been running these bikes have some possible solutions? Thanks JJ