##### 



Exhibit 12.1 CERTIFICATION OF CHIEF EXECUTIVE OFFICER PURSUANT
TO SECTION 302 OF THE SARBANES-OXLEY ACT I, Teo Tong Kooi, certify that:  1.
    
    I have reviewed this annual report on Form 20-F of China Yuchai International Limited (the
Company);  2.
    
    Based on my knowledge, this annual report does not contain any untrue statement of a material
fact or omit to state a material fact necessary to make the statements made, in light of the
circumstances under which such statements were made, not misleading with respect to the period
covered by this annual report;  3.
    
    Based on my knowledge, the financial statements, and other financial information included in
this annual report, fairly present in all material respects the financial condition, results
of operations and cash flows of the Company as of, and for, the periods presented in this
annual report;  4.
    
    The Companys other certifying officer(s) and I are responsible for establishing and
maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and
15d-15(e)) for the Company and have:  (a)
    
    designed such disclosure controls and procedures, or caused such disclosure
controls and procedures to be designed under our supervision, to ensure that material
information relating to the Company, including its consolidated subsidiaries, is made
known to us by others within those entities, particularly during the period in which
this annual report is being prepared;  (b)
    
    evaluated the effectiveness of the Companys disclosure controls and procedures
and presented in this report our conclusions about the effectiveness of the disclosure
controls and procedures, as of the end of the period covered by this report based on
such evaluation; and  (c)
    
    disclosed in this report any change in the Companys internal control over
financial reporting that occurred during the period covered by the annual report that
has materially affected, or is reasonably likely to materially affect, the Companys
internal control over financial reporting; and  5.
    
    The Companys other certifying officer(s) and I have disclosed, based on our most recent
evaluation of internal control over financial reporting, to the Companys auditors and the
audit committee of the Companys board of directors (or persons performing the equivalent
functions):  (a)
    
    all significant deficiencies and material weaknesses in the design or operation
of internal controls over financial reporting which are reasonably likely to adversely
affect the Companys ability to record, process, summarize and report financial
information; and  (b)
    
    any fraud, whether or not material, that involves management or other employees
who have a significant role in the Companys internal controls over financial
reporting. Dated: July 15, 2005 By:
    /s/  Teo Tong KooiName:
    Teo Tong KooiTitle:
    Chief Executive Officer and Director




---



##### 



Exhibit 12.1 CERTIFICATION OF CHIEF FINANCIAL OFFICER PURSUANT
TO SECTION 302 OF THE SARBANES-OXLEY ACT I, Philip Ting Sii Tien, certify that:  1.
    
    I have reviewed this annual report on Form 20-F of China Yuchai International Limited (the
Company);  2.
    
    Based on my knowledge, this annual report does not contain any untrue statement of a material
fact or omit to state a material fact necessary to make the statements made, in light of the
circumstances under which such statements were made, not misleading with respect to the period
covered by this annual report;  3.
    
    Based on my knowledge, the financial statements, and other financial information included in
this annual report, fairly present in all material respects the financial condition, results
of operations and cash flows of the Company as of, and for, the periods presented in this
annual report;  4.
    
    The Companys other certifying officer(s) and I are responsible for establishing and
maintaining disclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and
15d-15(e)) for the Company and have:  (a)
    
    designed such disclosure controls and procedures, or caused such disclosure
controls and procedures to be designed under our supervision, to ensure that material
information relating to the Company, including its consolidated subsidiaries, is made
known to us by others within those entities, particularly during the period in which
this annual report is being prepared;(b)
    
    evaluated the effectiveness of the Companys disclosure controls and procedures
and presented in this report our conclusions about the effectiveness of the disclosure
controls and procedures, as of the end of the period covered by this report based on
such evaluation;(c)
    
    disclosed in this report any change in the Companys internal control over
financial reporting that occurred during the period covered by the annual report that
has materially affected, or is reasonably likely to materially affect, the Companys
internal control over financial reporting; and  5.
    
    The Companys other certifying officer(s) and I have disclosed, based on our most recent
evaluation of internal control over financial reporting, to the Companys auditors and the
audit committee of the Companys board of directors (or persons performing the equivalent
functions):  (a)
    
    all significant deficiencies and material weaknesses in the design or operation
of internal controls over financial reporting which are reasonably
likely to adversely affect the Companys ability to record, process, summarize and report
financial information; and(b)
    
    any fraud, whether or not material, that involves management or other employees
who have a significant role in the Companys internal controls over financial
reporting. Dated: July 15, 2005 By:
    /s/  Philip Ting Sii TienName:
    Philip Ting Sii TienTitle:
    Chief Financial Officer and
Director