Hello Hansung
If you experienced a slipping clutch as described in Rotax SB-916 i-003 / SB-915 i-014, please contact your local Rotax distributor or Rotax service center for more information.
In the certified version of the SB, refer to Section 2 - Material Information, Subsection 2.2 - Company Support Information, which states:
Price and availability will be provided on request by ROTAX® Authorized Distributors or their independent Service Centers.
Any possible support by BRP-Rotax GmbH & Co KG will be provided on request by ROTAX® Authorized Distributors or their independent Service Centers.
(See attached)
Here is where you can locate your local Rotax representative: https://dealerlocator.flyrotax.com/