Welcome, it sounds like you are making awesome progress. These good old bikes take some patience and time to fully understand and get running right. I'm on the tail end of getting my bike set up just right and every day I learn something new. When it comes to carbs, i suggest a FULL disassemble, part by part cleaning and inspection for wear. Also before taking it apart grab a parts diagram so you know what's in there. Some of the small springs can fly off under compressed air and try not to bend or break anything.
So back to your bike... here is what I suggest:
- Start with points and make sure both sides are clean and with the right gaps (buy a new set if they look bad), if you can't get them to stop arcing back to the plate (backfiring exhaust), then the condensers are bad (but not typically)
- Set the timing per the book (no need for a strobe light)
- Test/measure the coils for proper voltage range
- Remove the spark plug wire caps and properly clean the connections (I use Deoxit for all electrical connections, it's made for electronics and works great on improving connectivity).
- Set the air/mix screws on the bottom of the carbs to spec, they control the rich/lean mixture ratio.
Take good notes on everything you do. Don't change too many things around in one pass so you can cancel out the work you are doing and isolate the problem.
I chased a cold manifold pipe thinking it was a clogged jet, Pulled the carb cleaned the corresponding carb, put it back in and no change. Checked compression (good). Cleaned the plug caps, no change. Switched the spark plug to another location - there it was, now the other pipe was cooler. the moral of the story is to keep it simply and focus on the obvious first. My plugs had 200 miles on them, but 1 went bad (don't use the cheap Champion plugs to save $5).
And don't use WD40. Carb cleaner should be used to check carb leaks - not sure where you got brake fluid from.
...just my 79 cents - good luck
