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Exhibit 12.1 CERTIFICATION PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002 I, Wrixon Frank Gasteen, certify that: 1. I have reviewed this annual report on Form 20-F of China Yuchai
International Limited; 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
registrant as of, and for, the periods presented in this annual report; 4. The registrant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 registrant 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
registrant, 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 registrant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 registrant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 registrants internal
control over financial reporting; and 5. The registrants other certifying officer(s) and I have disclosed, based on
our most recent evaluation of internal control over financial reporting, to the
registrants auditors and the audit committee of the registrant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 registrant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 registrants
internal controls over financial reporting. Dated:
June 29, 2004 /s/ Wrixon Frank Gasteen
By: Wrixon Frank Gasteen
       Chief Executive Officer




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Exhibit 12.1 CERTIFICATION PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002 I, Philip Ting Sii Tien, certify that: 1. I have reviewed this annual report on Form 20-F of China Yuchai
International Limited; 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
registrant as of, and for, the periods presented in this annual report; 4. The registrant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 registrant 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
registrant, 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 registrant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 registrant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 registrants internal
control over financial reporting; and 5. The registrants other certifying officer(s) and I have disclosed, based on
our most recent evaluation of internal control over financial reporting, to the
registrants auditors and the audit committee of the registrant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 registrant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 registrants
internal controls over financial reporting. Dated:
June 29, 2004 /s/ Philip Ting Sii TienBy: Philip Ting Sii Tien
       Chief Financial Officer and Director