[Yendor]

That looks like a beautiful survivor of the bike and in very good condition.
If as you say it was PROPERLY Put Away then your really in luck.
Most are just parked and forgotten.

Do you have a copy of the FSM (Factory Service Manual)?
Without it you likely have very little success in getting this bike operational.
There are Links to download PDF versions on this site.

It will need a FULLY charged Battery, these are Battery Excited Ignitions.
The Charging system does NOT put out anywhere near the required Voltage/Current required for Spark.
It doesn't even break even at an idle, actual charging doesn't start until approx 3K RPM.

The Points are behind the Left Side OVAL Shaped Cover just above the Spark Plug.
I would take some 600 Wet/Dry paper to the contacts (both sides) then clean with spray contact cleaner or a Cloth wet with Acetone or Denature Alcohol.

One other thing - Get a Set of JIS Drivers (Japan Industrial Standard). - What "LOOKS" like Phillips are not and will often just strip out it you use a Phillips.
JIS Drivers have a very different angle to the Tips.

 

[Yendor]

Clymer's manuals have been found to have a lot of errors - Download a Factory PDF version.
Here is a Link to it on the Common Motor Collective.com

Honda CL350 SL350 CB350 Factory Service Manual Searchable.pdf

drive.google.com

A Hand Impact Driver is a Blessing on many of these bolts.
Also I usually Spray DAILY with PB Blaster or other Penetrating Oil and let sit over a few days before going after stuck bolts.
Patience and lots of it will get you thru.

Ultra-Sonic cleaners are great.
BUT... There are FELT Seals that are greased on both ends of the Throttle Shafts.
If the Carb Bodies are just dunked the seals will be washed clean of the grease and you will need to remove them to re-oil (with 90 W gear lube or light grease) to make them seal again.
They are one of the GOTHA's in building these carbs. They will create a vacuum leak behind the throttle plates an cause lean condition that is really hard to find.

Getting to them is a bit of a Pita as the Choke Plates and Throttle Plates have to come out.
This is a place where the JIS Drivers are a MUST as the Screws are small and very easy to strip out the heads.

They were Staked at the factory to prevent them from coming out and getting swallowed thru the intakes.
Work them back and forth, then when re-installing use LOCKTITE.
Note: The Throttle plates are Beveled and MUST go back in correctly or they won't seat.

I could go on about rebuilding these carbs but...
There are some STICKY Posts at the top of the topics in all of the different sections.
The Carb Section has one on re-building these carbs it is a good reference.

Take Pictures as you go for reference on how to put things back