Here at Dan Vance Racing my goal for porting heads is to flow the most air at the highest velocities possible. The key to my success has been to remove as little material from the port that is needed, and raise the velocity as high as possible. The majority of the Harley heads were just to big to produce the high velocities needed to make good power in all rpm ranges. Now that the Motor Company (MOCO) is starting to build bigger motors the valve sizes are getting close to their optimal sizes. However the MOCO is now making the heads with smaller valves and ports. This is being done mostly to meet the new EPA regulations to controll exhaust emmisions but. i think the overall consensus is that the smaller valves and ports are creating higher velocities which is making the bikes more user friendly and making good torque. Unfortunetly the valve sizes are to small to support good horsepower in the upper rpm ranges in the bigger motors. This is where porters like myself have been able to capitalize on putting in a little larger valve and still maintaning good low end velocities and still have enough air for very good horsepower in the upper rpm ranges. In years past (I have been porting heads since 1980) we were only able to shape the ports with the material that was already in the port. Like other porters of the time we thought that bigger was better because we did not have the technology to to add material. We could use epoxies but after extended time the epoxy would fall out of the port and make a bigger mess. With todays better technology we can add material (wleding) and not be worried about our work falling out of the port. As I learned more and more I realized that if I made the port larger in some ares and smaller in other areas the flow numbers just got better and better, and the power the motors made were truly impressive for a two cylinder motor. One of my earlierest successes came at the 1995 AMI Brute Horsepower Shootouts that was held at Daytona Beach Bike Ralley. At this event I rode my bike (1986 fxr) over to watch and see what was happening. When I seen the HP numbers that were being made I wanted to put my bike on their dyno and see how I would do. I took off the air cleaner, took the baffle out of the exhaust pipe and put the bike on the dyno. At the end of the week I took the trophy home after recording 110.8 hp to the rear wheel. This resulted in my changing the direction of my business to making more power. With the introduction of the twin cam motors in 1999 the demand for bigger, more powerful motors was in full swing and I was ready for the change. The powersports industry started to make and sell performance parts at an unheard of pace. In todays world there is so many choices and products to search through that it can be a daunting task to try and figure out what was needed to make the bike run the way you wanted. The next several years were spent on the dyno and flow bench to determine what would make good power, be reliable, get good gas mileage and not cost a fortune to do. I have put together a list of parts that can satisfy almost any riders desires, from ultra fast to the bagger looking for more power to use on the highway and in everyday traffic. There are many combinations out there to choose from and unfortunetly I have not checked them all.
With the ability to now change the ports to enhance the flow in the lift areas of the chosen cam I have utilized two different port designs, one for the rider who is using a .500 lift cam and the rider who want a bigger, longer duration camshaft. This all accomplished by adding material to the inside of the port which promotes flow in desired cam lift areas.
Here is a picture of the heads and the parts I use. I start off by glass beading the combustion chamber and ports to remove the power coating and the carbon. I then remove the intake valve guides to make porting easier and more accesible. I will now remove material in the port to make it the correct size and shape. Then to the oven and then welding in the areas that are hurting the port flow. When the heads cool down I will finish my port work and repeatedly check my results on the flowbench. When I get the flow numbers I want I installed the vlave guides and do a valve job. I use a carbide cutter with all 3 of the valve angles i am using to be cut at once, I also put two angle cuts on the valve face which adds even more air. . At this time I will super polish the ports to a high gloss finsih which will allow me to inspect all areas of the port to check for imperfections. If everything is ok I take the heads go to the glass bead cabinet and blast the ports to a predetermined texture to assist the air and fuel to stay in suspension all the way into the port where they will recieved a spark for a controlled explosion to creat the power we want. Now that the heads have recieved the porting and valve work it is time for assembly. I thouroghlky clean all the parts with lacquer thinner, check all my measurements and record for future work and start the assembly process. After they are assembled they go back to the flow bench for the "to go" testing. If all test good I wrap then in a clear plastic wrap to keep out unwanted dust. They are boxed and return to the customer.
The parts that are included in this kit are: 2 new peformance valve guides, two new 1.900 hi-tulip intake valves and new spring to correct the spring pressure.
My heads can be set-up to accept most cams, all you have to do is tell me the cam choice.
