The heads were rebuilt and converted to desmo valve operation by RYE ( Ron Young Engineering )
Initially, these replacement heads required cleaning after living on a dirt floor for a number of years. They were cleaned by hand with degreaser and brushes from machinerycleanery. Green and grey Scotchpads were used for the flat faces on the fins.The results speak for themselves.
|The new inlet valve seats have been cut to allow the valve to be flush with the combustion chamber as with the 750SS. Compression is higher than the GT as a result. The squish bands were made concentric and matched. Stock Ducati valves are used with custom valve guides. On assembly the squish height was measured and matched between cylinders.|
|This detail image shows the cutaway and blending of the inlet guide where it protrudes into the inlet tract. The other inlet tract is similar, the marks around the perimeter on both heads are from calipers used to match the size and volume. What I can't show is the valve throat and seat work where Ron carefully blended for better fuel/air flow.|
|A different shape for the exhaust tract where the valve guide protrudes, the careful blending and matching pays dividends with even running. When you click on the image the blending of the valve seat to the port will be evident.|
conversion and cylinder head assembly was carried out entirely by Ron. All the rockers are now
polished as per 750SS spec. This conversion is not easy, each head has
to be measured and machined individually due to camshaft position.
There are some horror stories out there..........
The cams are VeeTwo roundcase desmo street/track ( V2-03-054 ). Brilliant !
head nuts came in two styles. Type 1 has 17mm head and a 2.7mm thick
washer. Type 2 has 16mm head and a flanged base replacing the
washer. The '71 and '72 models used the 17mm type.
Access is slightly easier with the 16mm flanged type.