“Help me obi won kanobi youre my only hope!”
Working away so only had the weekend to change my 1x setup to 2x on my gorilla monsoon, lbs booked up for at least a week so thought i would crack on.

Now the gear cable and sheath runs along the downtube from the shifter but then the cable leaves the sheath to enter the plastic routing on the bottom bracket before attaching to the front mech. There is no cable stop so how do i get round this. Im sure there was no cable stop on my salsa vaya either but that was acheived somehow?. Any advice would be very much appreciated!

You mean no stop for the sheath on the Down tube I take it?

Problem solvers make bolt on cable stops

https://www.sjscycles.co.uk/gear-spares/origin8-clampon-single-frame-cable-stop-black-286-mm/

You can also buy direct mount front mech. adapters and use a direct mount front mech. (the cable stop is part of the mech. itself).

Shimano side swing front mech is needed.

You don’t need a stop if the routing is under the bottom bracket…

Shimano side swing front mech is needed.

They only do mtb ones

Depends on the routing/mount but you can buy front mechs (Shimano) that have the stop built into the mech.

Sorry, down tube not seat tube. Would you need a bottom pull mech.?