Weak right cylinder

[Take Warning15]

I've been fighting with this bike for a few years now and I've almost got it. Two issues have yet to be pinned down though. One, a fuse that keeps blowing/ a short that I can't find. I'll get that eventually. But what is concerning me now is my right cylinder. It seems to not be making as much power as the left. The exhaust on the left is strong and consistent but the right is weak. Here's what I've done so far. Of course, I may have done a few things improperly, as many of use new to bikes do, so please take this list for what it is worth:

rebuilt the engine, both cylinders are just shy of 200lbs.
rebuilt the carbs and replaced stock jets.
checked float levels
adjusted valves countless times
made sure the battery is charged (never reads 14 volts @ 3k rpm, but is close)
checked timing/ timing chain
synched carbs- a side note on this- My first thought was that the carbs weren't synched. It would make sense that the right side is weak and the synch screw needs to be tightened. However, any more or less than where it is now leads to backfiring/ popping, etc.

The right side still does make some noise when decelerating.

Plugs are also reading a bit rich. They aren't soaking wet, but they are definitely black.

The bike has some aftermarket exhaust with baffles and a pamco ignition.

Trouble shooting suggestions?

 

[CDNTX650]

dbl post

 

[CDNTX650]

what are your mix screws at? you sure turning the sync screw some more wont make it kick in? using vac guages? or by ear?

 

[Take Warning15]

what do you mean no driving? Like running the bike but not driving it? My mix screws are at 1.25 out I believe. I forget exactly but I set them according to a chart that 5 twins posted. The carbs are from a 79 I believe. The more I turn the synch screw, the worse the popping and backfiring gets. it is difficult to turn it much more because the tank is all on but I can turn it half way in either direction.

 

[Take Warning15]

I'm trying to synch it by ear, but like I said, it isn't getting as strong as the left. I stopped adjusting it when the backfiring stopped. It still makes some noise but it is as good as I can get it. I figured once I solved the weak exhaust pressure, I'd also solve the popping sounds.

 

[CDNTX650]

What happens if you go out another half turn on the screws. If you are modded, that 1.5 turns is merely a guide.

 

[Take Warning15]

It gets even worse. It starts to stumble and run like crap. The thing that is throwing me is that the left cylinder is strong and sounds great.

 

[nghieplk]

Up. Im facing this exactly problem. The right engine is weak at idle (the weak sound on exhaust) but when I turn the throttle to go, it runs normal, powerful sound like the left. I tried to switch the plug but nothing happens.

 

[gggGary]

Basics done: valves, cam chain set, compression? Strong blue spark on both sides, timing set, checked?
Idle circuits cleaned set. Carbs synched?
Let it idle a while, then pull the plugs what do they look like?