Right cylinder stronger than left, XS400

Hey guys, question on the above topic.....
Before re-installing the gas tank, I got the bike started and idling off a temp tank (can and some fuel line) Idled nice and smooth......
Now with the tank on, the right cylinder seems to be much stronger than the left...idle not so smooth, lots of vibration..... hitting the throttle seems to kick the left one in stronger....

Differences are inline fuel filter...could that cause the problem?
Could the carbs just be out of sync?

More sinister problem waiting for me in the wings?

 

sounds like an out of sync issue to me.

Sync them up.

 

Cool, that's what I wanted to hear....
Now to build a ghetto sync tool

 

Still have a vacumm operated petcock on it ? If so, it may be leaking fuel into one intake.

 

Hmmmm
Yes , original petcock, just rebuilt (local shop did it for the same price of a rebuild kit).
Carb fuel intake is on the left side,.... right side is the stronger of the 2....
If not a sync issue, could it be float valve or float level issue?
Thinking I may have some clogging in the enrichment tubes as well.... if I use the choke, RPMS rise, but then drop off and will try to stall if I don't close it up.

Will be doing the sync today....will post results later

 

OK ,need to recharge my battery and make a rickcomatic restricter for my homebuilt manometer..... trying to sync, all the oil (used 2 stroke oil for safety reasons, thankfully) got sucked into 1 cyl.... soooo I need to retry the whole thing again later.... looking like the sync was way off or I have an air leak (though nothing showed when I did a wd-40 around the boots/carbs tes).

edit addition!!: ARGH!!!!, turns out my Duplicolor flat black high heat paint isn't very gas resistant.... a drop ate a nice streak down the side..... must've splashed a bit when I picked the tank to reassemble before putting it back in the shed....... Not the best day of work there I guess.....