The spring of the intake/exhaust valve can be compressed and the cotter can be detached without lowering the engine head.
Tool for compression of intake and exhaust valve springs.
Specifications
Adaptive size (mm): φ25, φ28, φ30, φ36
Hipeira valve spring compressor
Set contents / accessories: Main body x 1, valve adapter φ36 25 mm, valve adapter φ28 mm, plug hole air adapter (pneumatic plug) x 1, head hook hook x 1