Fat Stem Twin Cam valves
KIBBLEWHITE’S latest valves are its Fat Stem design for Twin Cam applications.
The introduction of the new valves comes as the result of reports that some later model H-D Twin Cam heads using 7.0mm valves may have a tendency to crack in the port end of the valve guide boss. The problem has been noticed on heads with the number 332 embossed on the cylinder heads.
To rectify this problem Kibblewhite is now producing its Black Diamond valves with plus .005in oversize stems for engine builders who need to re-establish correct valve stem to guide clearance, but do not want to take a chance on creating a crack, or worsening an existing crack by changing valve guides in the heads.
The oversize portion of the stem does not extend into the keeper groove area, so the OEM keepers may be used.