"The best you've ridden is the best you know." - Paul Thede


Power, Powerband, Longevity


Building a reliable, "World Class" engine requires a combination of state-of-the-art equipment and experienced, knowledgable technicians. Race Tech provides quality, precision engine services using the best equipment and processes in the industry.

The staff at Race Tech has over 65 years of championship-winning engine building and tuning experience formally educated by the world's most renowned engineers.

e provide precision services for ALL engine builders and tuners.

Please do not send in a complete engine. Components only (i.e. head, cylinder, crank).








Developing the best combination of porting, cam timing, mapping, and related components to build "World Class" engines is a painstaking process. Race Tech has spent an impressive number of hours doing R&D on the Flow Bench, Dyno, Rottler EM69P CNC, and at the Track.

If you follow the RT Power Plan™ and assemble the engine correctly you can build an engine capable of competing with anything in the world.



The RT Power Plan includes recommendations for:

4-Stroke Engines

  Full Porting (with possible addition of Epoxy) including a 5-Angle Radius Valve Job
  Cam and/or Cam Timing Changes
  Valves or Valve Mod
  Valve Seats (often for performance, sometimes for reliability)
  Valve Guides (if there is an issue with stock)
  Valve Springs
  RT ECU Mapping (for Race Gas and Pump Gas)
  Exhaust Pipe
  Also listed are specific concerns for that particular model.

  If something is not included in the RT Power Plan we are recommending stock.




2-Stroke Engines

  Head Mod
  Exhaust Pipe


To view the Race Tech Power Plan go to to the Engine Section at the bottom of Product Search.


Engine modifications are for RACING ONLY! Not for highway (DOT) use.



Race Tech has a Rottler EM69P 5-Axis CNC Porting machine to provide the most accurate, consistent, precision porting available.


ATTENTION TUNERS - Confidential Port Digitizing Available

Tuners can have their head designs digitized and ported on the RT Rottler CNC. We keep your port designs completely private and provide a Non-Disclosure Agreement. You can take advantage of precise, repeatable, CNC porting without worry.


Head porting is for RACING ONLY! Not for highway (DOT) use.


3-Angle vs 5-Angle Valve Job
Notice the Valve Seat Width is the Same

With years of using nearly every valve cutting tool available, Race Tech selected the Rottler SG7 as the best machine for high quality, precision valve jobs.

A precision Valve Job is the core of a high-output, reliable engine. Race Tech uses a Rottler SG7 to provide a dependable, accurate, highest quality valve job. 

Outstanding Concentricity - It is common for stock heads to have .003" to .005" runout. RT Valve Jobs have guaranteed concentricity of better than .001". 

Superior Sealing equals More Power - Every head is Vacuum Tested and only passes if the sealing leakdown is better than 1%. 

A spec sheet is included with each head.


 - Standard 3-Angle Valve Job

A Standard 3-Angle Valve Job maintains factory designed flow and horsepower.


 - Hi-Performance 5-Angle Radius Valve Job

A RT Hi-Performance 5-Angle Radius Valve Job adds horsepower without sacrificing reliability. The area around the valve seat is the most critical area of a port. A 5-Angle Radius Valve Job creates the best flow possible by adding additonal angles and a radius. This increases air speed and flow over a 3-Angle Valve Job.


RELIABILITY 3-Angle vs 5 Angle - The Top Tuners in the world all know a 5-Angle Radius Valve Job has superior flow while providing the same reliability as a 3-Angle Valve Job. The reason for the reliability is simple - the seat width is exactly the same.



  - Valve Seat Installation

Race Tech can precisely remove and replace valve seats.

Sometimes even brand new stock seats need to be replaced. If the stock seats are poor they are replaced for reliability. Sometimes seats are replaced for better flow caracteristics and power.


 - Valve Guide Installation

New valve guides are installed and precision honed to the correct tolerance. When guides are replaced, a valve job must be performed to ensure proper valve alignment. These two steps create valve to seat concentricity better than .001". 

On certain models brand new stock guides are replaced if there is a known reliability issue.


 - Valve Refacing

With our valve refacer, we can create backcut angles to further improve flow on many Titanium Valves. Steel valves can often be resurfaced.



RT HI-Performance Ti Valves

 Hi-Performance Ti Valves

When a stock valve can be improved significantly we have designed our own. These Valves increase flow as much as 3 CFM while improving velocity at the same time. This means an improvement in both Peak Power as well as Bottom End.
Currently KX250 and YZ250F valves are available. Check out the Product Search.



RT HI-Performance Valve Seats


 - Custom Valve Seats 

Race Tech manufactures custom valve seats for almost any engine including automotive. We use Moldstar 90 material which is compatable with Titanium as well as Steel valves.

Custom Valve Seats require a design fee and a setup fee. We need some basic dimensions including OD, ID and Seat Height. Please download and print the Valve Seat Form then give us a call for details 951.279.6655 Engine Dept option 4. Or you can send us your head and we will design the Seats.


 - Stock Valve Seats 

We also have many seats that don't require design and setup.




Engine modification is for RACING ONLY! Not for highway (DOT) use.


Race Tech's head porting provides an increase in both flow and velocity to gain peak horsepower as well as powerband. Race Tech porting is developed using a combination of flow bench and dyno data.

A Valve Job is part of the porting process. A 5-Angle Radius Valve Job is used for the highest performance.



 - Race Tech Pocket Porting

Race Tech's innovative Pocket Porting™ provides 75% of the flow and velocity gains available while maintaining a great price point. The graphics at the left show the importance of the four port sections. Notice that 40% fo the gains possible are very close to the valve seat opening. A whopping 75% of the total potential is covered only slightly further down the port (40% plus 35%). By focusing on these areas we can provide the best bang-for-the-buck.



- Hi-Performance Full Porting

Full Porting increase flow and velocity for maximum efficiency (from flow bench data). This option is available when cost is no object and you are looking for the best available. Includes modifying the combustion chamber.



 - Hi-Performance Full Porting with EPOXY

Certain models benefit greatly by actually making the port runners smaller. This increases velocity and low and mid-range power without sacraficing top-end. This modification creates the best power AND powerband. (Not required on all models.)



 - Head Decking

Head Decking can be done as a hi-performance upgrade or to repair a damaged head surface. Race Tech machines the surface flat to less than .0005". For hi-performance, head decking is used to tighten squish clearance and raise compression. Note that Cylinder Decking is often a better solution than Head Decking. Please call for details on your particular model.



 - Cylinder Decking

Cylinder Decking is available to repair a damaged cylinder surface or as a hi-performance upgrade. Race Tech uses a lathe with precision expanding mandrels and digital readout to maintain extremely tight tolerances. The surface of the cylinder becomes flat to less than .0005". Machining to raise the compression ratio is also available.



 - 4-Stroke Cylinder Head Rebuild

This service includes disassembly, reassembly and setting valve clearances. When complete you have a ready-to-run head.



 - Cylinder Boring

Race Tech uses a motorcycle specific boring bar to bore 2 or 4 stroke steel sleeved cylinders.



Race Tech uses a high-end Land and Sea chassis dyno equipped with a braking unit and AFR (air fuel ratio) measurement.

The braking unit provides steady-state dyno testing at all throttle positions and RPMs to produce precise mapping and jetting.

The Race Tech Dyno can run up to 500 hp and is able to measure anything from motorcycles to UTVs up to 50 inches wide. 


Race Tech has a mobile dyno unit available for trackside tuning and on-site runs at events.


CONFIDENTIALITY - We can dyno your bike and provide data sheets with complete confidentiality.



 - Precision Rigid Cylinder Honing


Precision Rigid Honing is a critical yet often overlooked and misunderstood component for producing reliable, repeatable horsepower.

Race Tech uses a Sunnen Precision Rigid Hone to provide a diamond finish using special stones for nikasil (these stones are critical).

Precision Rigid Honing is an essential process EVERY TIME a piston ring is replaced. This is true for all cylinder materials but especially true for chrome and nikasil bores.

DO NOT USE BALL HONES! A precision rigid hone is typically good for 1 to 1.5 HP over a ball hone on a 250!

Some brand new cylinders (like YZ250Fs) have cylinders that are often out of round by over a half thousandths of an inch. This causes smoking and loss of power. These cylinders should be rigid honed before use.

 - Valve Guide Honing
When a new valve guide is installed it must be honed to correct tolerance. Honing the valve guide is another often overlooked, yet critical piece of building a high performance engine.



 - Soda Blasting

Race Tech uses an ABS Products Soda Blaster to produce a like-new finish to decarbon and clean engine components. We use a Soda Blaster instead of a bead blaster because it prevents the possibility of leaving abrassive material (glass/sand/egg shells) behind that can damage an engine. The Soda Blaster cleans using non-abrasive baking soda at extremely high pressures.


 - UltraSonic Cleaner

The Pro UltraSonic uses high frequency waves with a special cleaning solution specifically for engines to provide a like-new finish.

The little things count!



Race Tech has a custom built, computerized, state-of-the-art Flow Bench capable of flowing 28 inches at 600 CFM (yeah... those are big numbers - don't stand too close). It is an essential part of the R&D process developing the RT Power Plan.

Utilizing a pitot tube and Port Flow Analyzer Pro Software with fully digital air flow measurement, RT can provide flow graphing, as well as port velocity mapping.

RT also does Wet Flow Analysis.

CONFIDENTIALITY - we can flow test your head and provide you data sheets with complete confidentiality.





Using a special assembly jig Race Tech replaces the connecting rod, pin, and bearing; then trues the crank assembly to a run-out of less than .001". Includes spec sheet.




Race Tech offers Vortex ECUs and Custom Mapping Services. 

We stock Vortex Ignitions for many models with the standard base map installed.

RT has developed maps for many stock models that outperform the standard base map.

RT has developed maps for our RT Power Plans.

RT has developed maps for many other modified component packages.

Race Tech can develop a custom map for your specific engine package.


Vortex ECUs are for RACING ONLY! Not for highway (DOT) use.




After years of experience and testing, CP has become the trusted piston supplier for Race Tech Engine Services. CP Pistons have proven to be durable and reliable with excellent performance. 

Race Tech recommends and sells CP Pistons. We keep many models in stock.




Race Tech has done a lot of research and recommends FMF Pipes.

FMF Pipes can be obtained directly through Race Tech.



 - RT Valve Spring Compressor

If you build a significant quantity of 4-strokes you are going to love this tool! RT has created a Valve Spring Compressor that makes disassembly and assembly of heads quick and easy. It is foot-operated and has a slide hammer built in for stubborn keepers. Includes 3 size drivers for small to large motorcycle and automotive engines. You will love it!

TESC 01 - Add to cart




At Race Tech you have options:

  1. Send your Engine Components in for Hi-Perfomance Machining
  2. Have your Motorcycle Dyno Tuned & Fuel Mapped
  3. Call Race Tech to order components or with questions: 951.279.6655 
  4. Many Race Tech Centers can do high quality engine assembly. (We do not build complete engines at RT)

Our customers' satisfaction is vital. We put it in writing. ►Read More!


Race Tech specializes in providing precision engine machining and R&D services but we do not build complete engines. If you're looking for a trusted source to build your engine, the following Race Tech Engine Service Centers exclusively use RT for their machining services.













    ►Top End Rebuild 2016 Honda CRF250R