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Home » Technology

Nucleus Sport Elite Valves & Guides for Harleys

The Cylinder Head Shop introduces the Most Radical Valves Ever Designed for Harley-Davidsons.

The Nucleus Sports Elite FDS valves are made to the same exacting standards as all the others in our range and of the same high quality materials.

Note the special FDS Flame Deflector Stem on the exhaust valve. Although no heavier than a standard valve, in fact it is 15 gms lighter, this valve feature is designed for the unusual “right-angled” ports of the American twin. It has an anti-reversion feature on the port side lip and the fire face is shaped to allow gases to exit faster.

Over the years that we have worked on Harleys and Indian of all shapes and sizes, up to 2,000 cc drag racers and have noticed a tendancy of them to burn out the tip of the exhaust guide. On many heads, this is literally carbonised and crumbles on machining.

As the escaping flame and burning gases leave the combustion chamber, a certain proportion roll around the exhaust valve and down the stem onto the exhaust guide tip heating to near melting point. This deflector is designed to flip the gases out into port and down the exhaust.

The inlet valve has a very subtle tulip shape. Its fire face has been specifically design to continue the rolling motion of gases as the valve opens. This increases the charge into the combustion chamber creating the potential for a more powerful detonation. Both are made out of Stainless Steel and Tuffride finished to 72RC Rockwell hardness.

The guides are again of a superior and unique design, the inlet being tapered and the exhaust both slightly shorter and having a snubbed nose. Both are made out of Colsibro, a high nickel alloy with superb heat dissipation qualities used in Formula One by the top sports team.

Tolerances between valve and guide are half a thou on inlet and one thou on exaust, if we or other specialists fit them to size. One and a half thou if sent out for home fitment. Diamond honing equipement is necessary. This is slightly less than the tolerances of the new 4 valve heads (1.6 to 2.4) and much less than std where tolerances of 3 to 4 thou are common.

Any Harley, Indian or other “American V- twin” replica engine owner looking for quality, high mileage longevity and improved performance has found a new option to consider.

We argue that they are the most intelligent option.

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