Help

[renoso]

I recently purchased a 1993 Yamaha XJ600 and I’m trying to get working. Originally it would not start and previous owner said it had something to do with the carbs. I cleaned the and rebuilt the carbs, synced and set the correct float height for all 4. Now it will start but only after what feels like forever and when it is first started it will randomly hold high rpms even after letting go of throttle. After it finally warms up that all settles out but my right exhaust is blowing less, and colder than the left with random pops and some white smoke (I don’t think it’s blue). It will run and respond well at high rpms this all really only happens at low rpms. I’m really in denial that it one of the pistons and I’m still hoping it’s something else. I have replaced spark, check compression with just my finger, rebuilt the pet cock and like I said overhauled the carbs. The only things I am waiting on right now is new air seals for the bottom of the carbs as they are starting to crack. Just looking for advice or ideas of what I could do next or what it could be.