One of the bottlenecks of the HD ports is the short side radius.  The air wants to take the shortest path and that is the floor of the port.  It also doesn't like to make sharp turns.  To address both of these issues, I flatten the floor somewhat, which creates more area, and I smooth out the radius leading to the valve and the combustion chamber.  This allows more air flow in the area that is restrictive.  I also reduce and reshape the boss extending into the port around the valve guide to help the air flow separate and flow more cleanly around the valve guide. The bowl area transitioning to the valve seat is reshaped to optimize flow from the valve guide area to the valve.

  In the combustion chambers, I smooth and lightly polish the walls after blending. The smooth transition from the seat to the chamber helps increase low lift flow and the polishing helps prevent carbon build up.  I don't try to mirror polish because it really does nothing for performance and is very time consuming.

  The intake port is given a specific directional texture finish that will help prevent the fuel from separating out of the air stream and promotes better atomization of the fuel.  Liquid fuel doesn't burn - the vapors do.  The more the fuel is vaporized, the more efficiently it will burn, producing more power with less fuel and less chance of detonation.  For Stage 2, the intake seats are opened up for the larger 1.90" valves and blended to the bowl and the combustion chamber.  This along with a three angle seat promotes excellent air flow between the valve and the seat.  The valves I like to use have a 28° radius on the back side of the valve to help the air flow around the head of the valve and into the combustion chamber.  I don't enlarge the port so much that velocity is reduced to a level where low end power and drivability are sacrificed.

  The exhaust ports on most Twin Cam heads are very restrictive and need a lot of attention.  The exhaust valve size is not the problem with these heads so I retain the stock valves.  I do a lot of the same work to the exhaust port as the intake. The difference is the exhaust port gets enlarged in the area that has been reduced so much, then I smooth it like the combustion chamber.  The smoother surface actually has less surface area and will absorb less heat.  Less heat absorbed by the head in the combustion chamber means more heat in the combustion process and more pressure on the top of the piston.  Less heat absorbed by the exhaust port means hotter exhaust gasses and higher exhaust gas velocity.

  The valve guides that I use are cast iron and made by either Kibblewhite or Rowe.  They usually utilize OEM style valve stem seals or any direct replacement seals.  Optional with Stage 1, and included with most Stage 2, are new high-performance valve springs.  '05 and later heads can be retrofit to the earlier parts if needed, or we can work with the stock-style performance components.

  Throughout this entire process, I check my work at numerous stages using my Superflow flow bench.  I always keep in mind which cam(s) will be used and the desired final performance goals of the customer.    I can also mill heads to accommodate any desired compression ratio or to correct for any imperfections in the gasket surface.

  The intake manifold is an extension of the intake port and should not be overlooked.  A lot of flow gain can be had in the manifold.  For most carburetor manifolds, I reshape the short side of the manifold, similar to the intake ports, and give it the same directional textured finish.  I have found that these methods of modification produce great  performance and efficiency.  For fuel injected bikes, the throttle bodies should also be improved for maximum performance.

  Just as every person is different, so is every build.  I always like to talk with my customers to find out what type of performance they are looking for, and what is their style of riding.  Only then can I help them determine what parts may work best to get them where they want to be, and I make sure that my head porting is always matched to the whole package.  If you have any questions, please feel free to call or email me.  I can help with any kind of build and I'm happy to answer any questions the best that I can.

     - Hammer

Not sure which level of porting is right for you? No problem!
Call or email with your specs and we'll make a recommendation.