I'm using the code
local model = workspace.World
local cframe = model.PrimaryPart.CFrame
wait(3)
model:SetPrimaryPartCFrame(cframe * CFrame.Angles(0, math.rad(0), -90))
I set the Primary part of the model, and put the rotation value to -90, yet everything is rotating more than that.

2 comments
What rotation is your goal?
-90, instead its doing about -117 for some reason