The thrust blocks are the connection in the engine between the shift arm and the shift claw. They transmit the angular momentum of the shifter on the handlebars to the shift claw in the engine.
The BGM thrust blocks are made of wear-resistant and high-strength 42CrMo4 material.
They renew the shifting precision as it was originally available.
They should therefore always be replaced if the original blocks show signs of wear and/or a reinforced shift spring is used.