Jump to content

Apex Technical Innovations Billet Cylinder Head Kit - 2 Dome Reviews

Read and compare owner reviews & ratings of Apex Technical Innovations Billet Cylinder Head Kit - 2 Dome. Product specs, photos & video, pricing, and more!

Product Information

  • Price Range $265.00 ~ $315.00 Shop Now
  • Rating
      (Read 4 reviews)
  • Submitted
  • Last Review

8 Screenshots

Product Details


   4 of 4 members found this review helpful 4 / 4 members

What Is It?

Apex Technical Innovations 2 stroke heads are designed for each application to increase performance where you need it most. Less jetting woes, improved fuel economy, better throttle response and of course, increased power. The SX/XC dome gives a big mid-range boost with more power everywhere on the front side of the power curve. Apex offers head kits and OE head mods for the big 4 Japanese brands plus KTM/Husq/GasGas & Beta applications.

Two piece design allows for interchangeable combustion chambers (domes) to suit the power characteristics of any riding style.


Tools Needed:

  • Basic Hand Tools
  • Micrometer or Calipers
  • Torque Wrench
  • Rosin Core Solder

The detailed instructions made installation a breeze. I had a few questions regarding my squish clearance once the head was installed and a call with Matt @ Apex got me squared away quickly.

Fit and Finish

The Apex head fits as it should and the machining and anodized finish looks incredible. It really gives the head a nice “bling” factor.

Your choice of raw or anodized blue finishes.


Before you read my take on how the Apex head performed, I think it's important to understand my skill level, terrain ridden, the test bike and its mods.

Rider Information:

  • 34 year old Vet A Rider, 180lbs.
  • Most of my riding consists of XC style courses with a mix of roots, rocks, creek crossings, hill climbs and open field sections.

Test Bike & Mods:

  • 2006 Yamaha YZ125
  • Pro Circuit Works Villopoto Pipe Paired with R-304 Silencer
  • YZ125X CDI Box
  • 93 Octane Pump Fuel with Castrol 927 32:1

I was instantly impressed with how clean and responsive my bike ran with the Apex head. The head provides broad and snappy power throughout the front side of the power curve. My riding style is more that of a lugger; with the Apex head, I have the bottom-end power to carry a taller gear more effectively. This was very beneficial when tracks got slick; I was able to ride a gear higher and find traction while carrying more speed to pull me through obstacles.  Additionally, the Apex head increased my confidence because the added bottom-end would help me recover more easily if I made a mistake or found myself in the wrong gear.

The SX/XC dome is designed to provide a low to mid-range power boost and while doing that, I also felt that this dome improved power throughout the RPM range. No question that it pulled a little harder and longer vs. the stock head. I race in an open displacement class where passing 450s can be difficult , but the extra low-end pulling power made it easier to secure passes throughout the entire track.  I found myself making passes quicker and easier; over the course of a 2+ hour race, not only was this more enjoyable, I was more competitive.

OE Fit & Finish.

Final Thoughts

If you are looking to get more mid-bottom end out of a Yamaha YZ125, an Apex head with the SX/XC dome is a must-have. I love how clean and responsive it made my bike feel,  improving the connection between the throttle and rear wheel. The significant boost in power low to mid makes the bike more exciting to ride, but also easier and more competitive when racing against more powerful machines.

Brandon Ricks - IMG_2742.1.jpg
The Apex Racing head looks great, but provides tangible rider benefits.

  • Like 3
  • Helpful 2

Share this review

Link to review

   2 of 2 members found this review helpful 2 / 2 members

I’ve had the Apex head on my YZ250 for a little less than a month now. 

One of the best things I’ve done to this bike. 

I decided to call an talk to someone before ordering and was glad I did. 

Matt was incredibly helpful and after getting some information from me about the bike and type of riding, he recommended the SX dome.

Without talking to someone first, I would have assumed that the XC dome was what I should have ordered.

The new head fixed the squish and is also a more tailored to my riding.

After years of dealing with excessive spooge caused by the squish being too large from the factory, this finally cleared that up.

The bike runs so much cleaner and jetting is much less finicky.








  • Like 3
  • Helpful 1

Share this review

Link to review

   1 of 1 member found this review helpful 1 / 1 member

The best modification I did to my YZ250X. I put the XC dome on for mountain single track and the thing lugs super well. The support and product are two thumbs up. 

  • Like 3

Share this review

Link to review
DM David

   1 of 1 member found this review helpful 1 / 1 member

This was by far the best modification I did to my 2021 Yamaha YZ 250. And the customer service support I received from the owner Matt Deneke  was above and beyond. 




  • Like 4

Share this review

Link to review
  • Create New...