Zephyr wont pull off

The most likely thing is a sticking clutch. With the ignition off, can you drop it into second gear and push it with the clutch pulled in? You say you put 'new petrol' in, so it sounds like it has been stored for a while. Clutches will often stick as the clutch plates have been under pressure for so long. Fully warm the engine before moving off until the plates free up.

And it looks like you probably mean VS1400 not VS400!

There is help here

https://www.google.com/search?q=suzuki+intruder+vs1400+stalls+when+put+in+gear

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Yes, there IS a clutch safety switch.

http://www.bikebandit.com/houseofmotorcycles/2005-honda-shadow-aero-750-vt750c-handle-switch/o/m151126sch409843

Item #8

when was oil last changed sounds like clutch plates sticking

with the engine off put it in gear pull in the clutch if you can't move the bike the clutch is dragging and needs adjusting

u need to adjust the free play in the clutch lever

Saftey circuit issue! check clutch switch, side stand switch and wiring these are connect to the neutral light switch and the 3 are part of the saftey circuit,
circuit is designed to cut the bike out if the stand is down and you kick it in gear also to stop the bike turning over & jumping forward when you hit the starter and its in gear and the clutch isnt pulled in.

weak stand spring my not be pulling stand onto the stand switch correctly there fore no making the curcuit, switches just make and break the curcuit.

change clutch cable maybe.

how cold is it out side

check that the side stand switch works with a multi meter. make sure you havent pulled a wiring plug apart when working in the carbs

First check that battery terminals are all tight. when bike has rested awhile battery picks up some charge may be enough to start it cold.