123 Crisp Dr, Americus, GA. 31719

Why should I give my head a port job?

An interview with Star Racing by 2Wheel Tuner Magazine

Call 800-841-7827 or E-mail for more information.

Stock ports with rough surface & protruding valve guides Star Racing finished ports are smooth with flush valve guides
Stock ports are rough & the valve guides protrude into the airway Finished ports are smooth & valve guides are flush

A better breathing engine is a key factor to more horsepower. The internal combustion engine is nothing more than an air pump, and the combination of parts comprising the pump are critical. The cylinder head of a four-stroke engine is made up of intake ports and intake valves, and exhaust ports and exhaust valves. This is how the air pump breathes. Camshafts actuate the valves, telling the head when to inhale and exhale. The fuel/air mixture enters through the intake ports and exits through the exhaust ports, so the shape of these ports greatly affect an engine's breathing characteristics.

Why should a motorcyclist invest money into porting their bike’s cylinder head?  Mass produced stock motorcycles have cylinder heads with generic port shapes.  The rough angles left behind by the casting process hinder the performance of the engine, leaving horsepower on the table.

If porting increases horsepower, does it reduce drivability?  The right combination of porting and valve work will increase horsepower while maintaining drivability and reliability.  The bike remains streetable, while overall performance of the motorcycle is increased.

What are the benefits of porting a cylinder head compared to turbo charging a motor or adding nitrous?  Porting the cylinder head, if performed correctly, will have no adverse effects on the engine.  The same cannot be said for turbo charging or nitrous, which puts strenuous loads on the engine, mainly on the lower rotating assembly.  While all three will increase the horsepower of the engine, porting the cylinder head can be combined with both turbo charging or nitrous to further enhance their effect.  The exhaust side of the cylinder head needs the most help when adding turbos or nitrous.  This is because a lot of air is being forced in, but nothing is being done to help get the increased airflow out of the engine. Turbos also have a very distinct sound and are easily recognized.  Nitrous, while concealable, is easily detected with a little investigation.  With port work, only the bike owner knows if their head has been ported.  These issues come up a lot at the local drag strip in deciding whom to race or not to race.

Should port work be included when installing larger pistons or high lift camshafts?  Yes, it is very important to have the cylinder head upgraded as well.  Remember the air pump analogy.  A one-size larger piston will usually be OK, but anything larger will actually start choking the engine.  The engine runs, but it is screaming for air.  The larger bore cannot be filled with the current head setup.  The head will have to come off and have larger valves installed and port work done to get the engine back to maximum efficiency.  This is why you should talk to a professional before starting a project of this nature. 

What are the different stages of port work?  At Star Racing we have four levels of port work beginning with the Street/Strip and continuing up to a Stage III.  The Street/Strip port work will remove all blemishes left behind by the factory casting.  A Stage I is basically the same as a Street/Strip but is usually accompanied by larger valves on the stock valve seats with additional port work to match.  A Stage II typically involves replacing the stock seats in order to install even larger valves.  The Stage III is an all out Pro Stock port job. 

What should I expect to pay to get my cylinder head ported?  Depending upon the type of head, prices start just under $700 and go up from there.  All of our levels of port work include a competition valve job.  We also will perform a thorough inspection of the head to check valves, springs and seals for wear. 

Is there any advantage to having bigger valves if I port the cylinder head?  Yes, to a certain degree, larger valves allow for additional port work, which increases airflow.  Increased airflow equals more horsepower and a faster bike.

Suzuki GS intake from stock to Pro Port
Stock Suzuki GS intake port with rough surface Star Racing Pro Ported intake Star Racing Pro Port job
We can even port your car head! See the Acura head below.
Acura stock port Port job on Acura in process Star Racing finished port work on Acura
Stock In process Finished product

Cylinder Head Porting by Star Racing:

Cylinder head work at Star Racing is done on the latest equipment.  We have the facilities to completely rebuild all motorcycle heads.  We stock all high-performance cylinder head components including valve guides, valves, valve springs, retainers and more.  There’s no waiting on parts like at some other shops.  We provide state-of-the-art work with a short turn-around time so you won’t miss a day at the track.  We even offer custom CNC duplication.  Have a port that you like?  We can digitalize it for you and repeat as often as needed.  Proprietary modeling will remain exclusive to your cylinder head.

Call Star Racing (800-841-7827) to get your cylinder head ported today - any make, any model. 1-2 week turn around. No down time.  Specials on Hayabusa porting.

Complete cylinder head enhancement, services include:

Competition Valve Job:  The most critical, high velocity flow around a valve is right at the valve seat.  The competition valve job focuses on this area.  The valve height is kept at a standard so you don’t lose compression ratio.  A competition valve job alone can yield approximately a 3% gain in horsepower.  

Porting:  Porting is by far the biggest single gain for a normally aspirated motor.  All port jobs come with a competition valve job.  Up to 30 to 50 horsepower gains can be expected on some applications.

Valves and Valve Seats:  To get more flow into a cylinder you can simply make the hole larger.  This is accomplished by the installation of larger valves.  We offer valves in a virtually limitless variety of sizes and materials.  In addition to standard oversizes, we can have custom valves made. 

Click for pricing and other machine shop services offered by Star Racing.

Print your work order form now.


Star Racing's air flow R&D makes racing headlines


Star Racing partners with Walsh Race Craft for

cylinder head air flow research and development

Official press release from Walsh Race Craft below. Walsh Race Craft

Star Racing partnership with Walsh Race CraftWalsh Race Craft has been developing and manufacturing top level ATV suspension components since 1997, what most people don’t know is that Walsh Race Craft has also been involved in engine performance, maintenance and development for just as long.

Though Walsh Race Craft had been cooperative with other engine performance companies for many years in the past, they took on the responsibility of their own engine program in 2008 with Jeremy Lawson on a TRX-450R in the professional motocross ranks, where they finished second place in AMA GNC racing.

They publicly released their engine expertise in 2009, after a stellar year with Cody Gibson on the Walsh Race Craft/Monster Energy/Kawasaki Team. Cody became the first person to win both Pro-Am championships in a single season, as well as winning the most races, leading the most laps and pulling the most holeshots of any rider in the two classes.

Since going public with their engine program, they have had a very pleasing success rating, they have not stopped offering the same phenomenal service they perform on their own race equipment and have continued to search for and make improvements in nearly every aspect of engine performance.

Their search for continued improvements is exactly what led them to Star Racing for their cylinder head air flow research and development needs.

They had started testing Star Racing cylinder heads in 2011 and have been very pleased with their performance and professional quality. In order to keep their engine program on the cutting edge of technological breakthroughs, Walsh Race Craft has developed a partnership with Star Racing for cylinder head air flow research and development.

Both Walsh Race Craft and Star Racing are excited to announce that this high level of engine performance is now available to you!

For all 450 cylinder heads, contact Walsh directly (386-364-4942 or sales@walshrc.com) to get Star Racing high performance port work.


Stage II port work & competition valve job

contribute to NHRA win

Star Racing stage II port work & competition valve job

David Primrose in the final round

David Primrose, of Cedar Rapids, Iowa, dominated the Super Pro Bike class at the NHRA Summit Racing Series West Central Division Finals in September 2011.

David's 1996 Kawasaki dragbike received stage II port work and a competition valve job from Star Racing that gave him the winning edge with a 5.702 seconds, 120.17 mph run to win him the West Central Division Finals in Super Pro Bike.

Here's what David had to say about Star Racing:

"Thank you for all of your help over the years and for making such a great product.

Please thank everyone in the shop for me, the cylinder head you did for me has worked flawlessly and has significantly increased the consistency of my et's to the point that I have won three track championships (2004, 2006 & 2011) and the 2011 NHRA division 5 championship. (Hopefully one more in Ponoma)

I truly believe I couldn't have done it without your help.



Cody Gibson & his Walsh Race Craft/Monster Energy/Kawasaki Team.

David Primrose wins West Central Division Finals on his '96 Kawasaki dragbike


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