I know a whole lot more about Webers than I do Dells. I have rebuilt Dells but only a couple pairs.
Webers? Too MANY!
A couple weeks ago I worked on a Thing with a Raby type 4 with DTM. Some people had worked on it that quite frankly were not qualified. After I re-adjusted the valves(3 were too tight) at loose zero, I checked the timing/ignition.
Then I turned to the carbs. He had a Spanish Weber on the left and a Chinese one on the right. Not a jet was the same: idle, main, air correctors all different. The accelerator pump jets were the same, but the squirt stroke was WAY off.
I swapped the Chinese carb for a Spanish 44 I had as a spare. Then I proceeded to re-jet so they all matched. The last offense that was committed was the linkage. The pickup off the throttle plate was way off(an inch difference) AND the one side had the linkage ear slid way down the hexbar to make room for the oil cooler hoses that run over the top of the shroud.
I should have taken pictures of what NOT to do. After moving the hoses and shimming out the linkage to make the downlinks the same length, then I slid the linkage arm over to get the same downward angle. Then I was able to synch them.
The customer told me that the Thing now ran as well as it had when he got it back from Jake about twenty years ago. Jake installed the motor himself, and my customer picked it up from his old shop in the early 2000s. Then drove it home to NYC.