Internal combustion engine

Abstract

A twin cylinder engine, includes a pair of cylinder members mounted to mounting surfaces of a crankcase, and cylinder heads mounted to the cylinder members. The cylinder members are modular components, which may be pre-assembled with components of the valve train as packaged units before the cylinder members are attached to the crankcase. Each cylinder member rotatably supports a cam gear which extends into the crankcase for driving engagement with the crankshaft. The cylinder members may be configured for either side valve-type (“L-head”), or overhead valve-type (“OHV”) engines, and the cylinder members may also be used in single cylinder engines.

1 - 18 . (canceled)  
   
   
       19 . A method of assembling an internal combustion engine having a crankcase, comprising the steps of: 
 providing a cylinder member;    mounting a cam gear rotatably to the cylinder member,    assembling other valve train components to the cylinder member, the other valve train components including at least one cam lobe, and at least one lifter; and    securing the cylinder member to the crankcase.    
   
   
       20 . The method of  claim 19 , wherein said steps comprise: 
 providing a pair of cylinder members;    mounting respective cam gears rotatable to the cylinder members,    assembling other valve train components to each of the cylinder members, the other valve train components including at least one cam lobe, and at least one lifter; and    securing the cylinder members to the crankcase.    
   
   
       21 . The method of  claim 19 , further comprising, before said securing step, the additional step of: 
 positioning the cylinder member with respect to the crankcase such that at least a portion of the cam gear extends into the crankcase.    
   
   
       22 . The method of  claim 19 , wherein said assembling step further comprises assembling at least one valve to the cylinder member.  
   
   
       23 . The method of  claim 19 , wherein said assembling step further comprises assembling at least one push rod to the cylinder member.  
   
   
       24 - 30 . (canceled)  
   
   
       31 . A method of assembling an internal combustion engine having a crankcase, comprising the steps of: 
 providing a cylinder member;    mounting a cam gear and lobe assembly rotatably to the cylinder member;    assembling other valve train components to the cylinder member, the other valve train components including at least one lifter; and    securing the cylinder member to the crankcase.    
   
   
       32 . The method of  claim 31 , further comprising, before said securing step, the additional step of: 
 positioning the cylinder member with respect to the crankcase such that at least a portion of the cam gear extends into the crankcase.    
   
   
       33 . The method of  claim 31 , wherein said steps comprise: 
 providing a pair of cylinder members;    mounting respective cam gear and lobe assemblies rotatably to the cylinder members;    assembling other valve train components to each of the cylinder members, the other valve train components including at least one lifter; and    securing the cylinder members to the crankcase.    
   
   
       34 . The method of  claim 31 , wherein said assembling step further comprises assembling at least one valve to the cylinder member.  
   
   
       35 . The method of  claim 31 , wherein said assembling step further comprises assembling at least one push rod to the cylinder member.