Valve adjustment 1986 Maxim X xj700

I'm looking to do a valve adjustment but I wanna make sure it's what I need before I do so. My bike takes forever to start up on a cold start. Once fired, I have to keep on the throttle, with very little throttle response, for it to stay running (choked or not). Then eventually it will rev normal and idle. Once at operating temp, it fires right up in like 2 cranks. I've gone through the carbs, plugs/wires, replaced my fuel filter, everything I could think of. I've seen one kind of similar post on reddit claiming it to be some sort of valve issue. I've done set screw valves on other things but never shim valve. I've done my research and get the gist of it. Is there any advice anyone could give me to solve my issue. Additionally, where would I aquire shims if I need to? Bike is a 1986 Maxim X xj700. Thanks in advance

 

Start with a valve measurement. If you're lucky it may not need any adjustment.
If an adjustment is needed, shims can be had anywhere, XJ4ever, Yamaha, Partzilla, even Amazon.
Budget at least a week down time between measuring, removing the out of spec shims, ordering and waiting on the new ones and buttoning it back up.
Have a look at the valve cover gasket, might need a replacement if still the original.

What have you done so far?
If they are clean- all passages flowing carb cleaner then;
Have you verified float levels?
Have you set all idle mixture screws?
Bench sync then running synch?