'78 XS400-2E - newbie synching carbs

Hey all! I've been trolling this forum since I got my Yamaha about a month ago. I'm new to the forum as well as new to getting my hands greasy.

I've learned a bunch of stuff from trolling this forum so this past weekend, I attempted to sync my carbs using the 'two-bottle' manometer method. The problem I have is that no matter the screw combination on the carbs (high on one side, low on the other and vice versa), the liquid still goes in one direction and never balances.

Here are some facts/observations that may help the diagnosis:
Both carbs are clean
There are no air leaks
Both adjustment screws are nice and pointy
The main idle screw (in the middle) adjusts the idle with no problem
Liquid always moves towards Carb 1 regardless of adjustment screw position
Spark plug on Carb 1 side is white
Spark plug on Carb 2 side is black
When I hold my hands behind the two exhausts, the Carb 2 side is far stronger than the Carb 1 side
Sometimes it dies when warmed up and idling but on the other hand, sometimes the idle creeps up and stays around the 3500 mark until I gently release the clutch until it drops. (I really don't understand this one)

Anyway, any wisdom that anyone can impart upon me would be greatly appreciated!

Carb synch should be that last thing in your equation. Have you checked compression? Valve clearance? Do those and try again.

Check for leaks again. Tear down the carbs and clean them again. I know you say they are clean and have no leaks, but there is obviously something amiss. Did you rebuild the carbs? New internals?

I'm not entirely sure Cylinder #1 is firing...or firing all the time. Believe it or not, it can be hard to tell. when the engine has been running a couple of minutes, dribble some water on the header pipe near the head on both sides and see if both sides sizzle and evaporate at roughly the same rate.

BTW- nothing personal here, but I never believe that "carbs are clean" until I hear: "bike's running perfectly, no problems."

Thanks for the advice. I didn't rebuild the carbs, just took the bowls off, removed the jets and cleaned everything. I was hoping I wouldn't need to completely remove them but sounds like I'll need to find a couple hours and do that. That could be a rookie mistake on my part!

Like I said, I'm completely new to wrenching my way around an engine. Could it be that the motorcycle is running from only one side and the other side isn't doing anything? (I don't even know if that's actually a thing.)

That is most definitely a possibility....and I suspect, what may be going on.

Thanks HoughMade! So what would be your recommendation as far as things I should check and in what order? (I realize this could be a loaded question with many different answers and if that's the case, I'll do some digging as to what steps I should take.)

Thanks for the input!

First do what I suggested above to see if both sides are running. If not, check the spark first. Just remove the plug, lay it so the threads are in contact with the block and crank it over if it sparks, then move on, if not, trace down why no spark.

If it sparks, put the plug back in and take the air filter off on the side that isn't running and spray some starting fluid or carb cleaner in with the engine running, if it starts firing then....and you will know, then fuel is the issue, usually meaning that your clean carbs are not so clean.

cool - will try that and post findings.

Welcome to the forum!