couple issues here, first one is that the bike will only run between full-3/4 choke,
Most common reason for this is plugged pilot jets
it has a dual output petcock on the tank and one line is plugged with a bolt, the carbs only seem to have a spot to hook one line, i don't know why the tank has 2 outputs, maybe its the wrong tank.
Or... a different year tank and fuel valve. Earlier carbs has two inlets and the fuel valve provided two supply lines.
i took the carbs off set the needle on the bottom to 1 3/4 turns out per clymer spec, also running 120 main jets with pod filters and 4-1 header.
The pods and header negate any stock settings in any manual that is about a stock bike.
The stock settings are to accommodate the stock air induction and the stock exhaust restriction. These carbs are too stupid to know what been changed, and don't feed fuel at an adaptive rate for the engine needs. Note the lack of sensors found on more modern vehicles?
i did take the tank off and set it on a ladder with a long fuel line connecting to the carbs, bike started with no choke and ran great, only problem is that carb #1 was leaking fuel out the overflow and then it started coming out the air filter.
The float valves are either sticking or you put too high a head pressure on them so they couldn't close. The overflow probably made the mix richer, partially compensating for the plugged pilot jets.
also there if a vacuum line coming off the carbs that is plugged with a screw.
It is not a vacuum line, it is a carb bowl vent. This allows air pressure to push fuel through the jets into the vacuum of the carb throat. Whoever plugged it was clueless.
should i assume the carb's aren't getting enough fuel and the long line while on the ladder acted as a buffer for them to get enough?
No. You should assume you need to look in your carbs (and tank) so see if they are clean (drop a bowl or two) And, make sure the fuel supply is clean with no rust particles. The pilot jets are only 0.016" in diameter. It doesn't take much to plug those.
Checking for head pipe heat can also tell you which corresponding carbs are most likely to have issues.
That second line off your petcock is a vacuum line. Try reconnecting the vac line from the carbs to your tank.
The stock bikes from 78 and earlier had no vacuum line for the fuel valve. There are also no standard vacuum ports from the intake tracts to feed such a device. Unless you pilfer a carb balance port.
Cheers,
