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Not enough information to come to a conclusion.
Was there a stroker crank part of this build?
Considering if the case boring was a perfect circle off Center? Note how thin on one side and not the other.
Looking at the case bore job alone several measurements should have been taken before final assembly.
Looks like the cylinder flange thickness is around .035, this is absolute Min. thickness.
I dont like to go below .039 unless a sleeve is cast in a cylinder.
Neglected to ask if a stock cylinder head and gasket was used? Squish would be stock bore side and the piston most likely hit the cylinder head.
From the looks of the sloppy Permatex job alone looks like a all around Butcher Job!

I think I have some Ti retainers that are CRN coated I can use.
I'll do a REM Isotropic Finish to the Valve Springs along with some oil Pump parts and the Gear Set, I can do that in house.
I haven't been able to match up any ti Valves with what I have in stock ie MX 150cc, 250cc and 450cc of all colors.
Would cost me $116. each to make them, and I work here!

Interesting read.
In the midst of my build I see the Valve springs as a real problem.
I have three new sets from various vendors.
Doesn't look like any thought or engineering is put into this area.
For instance, All the springs I have have the inner spring coils going in the same direction as the outer Spring. Huh? Valve train #101 this setup translates bad ju ju Harmonics. the inner spring's all look like a Coil out of a Spiral Binder, A stiffer spring just increases my seat pressure, then I need to look at a different material for Valve seats.
I have tried matching up to no avail with a high end PSI or PAC valve spring.
I'll post what I end up doing along with my opening and set pressures and coil bind mesurements.

In addition to the above with stock internals you have lost the Intake Velocity of the stock carb.
Way over intaked and carbureted.
You need the velocity to help atomize the fuel air mix better.
that 32mm is just dumping big drops in there
I don't think you will ever get it to run correctly with that set-up.
I recommend you just jet the stock carb,

The Product is pretty for doing at home.
One thing is I have had many "Bake" the Temper right out of the Piston. They go to Butter.
I'll use Polydyne or Swaintech.

Genuine Chrome bore requires a Moly type ring.More accurately Phosphate Coated Iron ring.
I haven't seen a OE Cylinder since 1979 Honda CR125 and 250.
Some old Kawasaki Sleds used Chrome, They'd flake
No issue as No O.E's or Re-Plating Co's use Chrome. (even U.S.- Chrome in WI).
Its all Nicol Silicon Carbide, theres some Phosphuros in there too, You can use a standard Stainless or TiN Coated ring.
Plated cylinders are used exclusively in all modern MX and Sport bikes.
I much prefer the Plating in the Powesports market.

I just recieved the 61mm, NCY kit, Its Alum.Cyl, with a Cast in Iron Sleeve.
I will be shipping to Swain Tech for a bunch of Coating's
Along with Cylinder head and valves.
Those Ol Briggs motors had Plated pistons.

Agreed.
I get discrepancy information from different from Vendors.
Wish I could find a BB Plated cylinder vs Iron Sleeve cylinder.
Iron is best used on the back yard BBQ for its heat retention properties. not mentioning its Thermal Expansion qualities.