Triumph 6mm Valve Stem Conversion Kit 650 and 750

Our installation notes for the Kibblewhite Black Diamond™ 6mm Triumph conversion should help anyone installing or considering this well designed kit.

Triumph 6mm valve stem Instructions

Kibblewhite offers a complete 6mm valve stem conversion for Triumph 650 and 750 heads. This well engineered and ultra light kit uses single "beehive" springs with titanium retainers, light weight keepers, and Black Diamond™ valves with .2350" (6mm) stems with Viton seals.

Triumph 650 racing head 6mm valves

The guides are machined for the included Viton seals and do not need any additional machining for valve clearance, no matter how huge the cam lift is. If you are building a serious Triumph engine, want to reduce the weight of your valve train, or increase airflow, this once exotic conversion is now available off the shelf. Kibblewhite Black Diamond™ valves are the best you can get for your Triumph motorcycle.These specially impregnated forged stainless valves have proven to have superior wear resistance and reduced friction than that of hard chromium or electrolysis nickel plating. When used with these C630 bronze guides and properly installed and finished, much tighter tolerances than factory can be used successfully for quieter operation, less friction, and much longer service life. 

This kit has also been successfully been used to set numerous land speed records both at Bonneville Salt Flats and El Mirage Dry Lake, without modification of any kind. We have also used it with Pre Unit 650 Iron heads both street and race.

Oversize valves and guides are available at the same price, although the guides are only available in standard (.501"), +.002 (.503"), and +.015" (.516"). We will answer any questions you may have that are not covered in the installation notes. 

These guides are not finish sized, and must be honed to size after installation to provide correct clearance. Recommended clearance in aluminum heads from Kibblewhite and Franz and Grubb are as follows:

Intake valve to guide clearance: .0010"

Exhaust valve to guide clearance .0015"

These clearances can be easily obtained by finish sizing both intake and exhaust guides to .2365" as the exhaust valve stem diameter is .0005" smaller than the intake. C630 bronze guides must be finished with a rigid mandrel type hone such as a Sunnen® P190 Honall.

We use a PSK6-A adapter with the BL6-235CS mandrel, and L6J67 stone in our Sunnen Honall. These recommended clearances are offered in conjunction with a thin film of moly type assembly lube on the stem on installation, and the assumption that the guide is finished straight and true, and that the valve seat is recut TO BE CONCENTRIC WITH THE GUIDE CENTERLINE.

Lash caps are available but not necessary, but due to the reduced valve tip diameter, proper rocker/valve geometry must be checked and corrected if necessary.

Triumph 6mm valve stem conversion


For Triumph 6mm valve instructions click HERE

Triumph 6mm valve stem Instructions



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