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  7. Tillotson JT-207 Performance Cylinder Head – Box Stock 196cc Clone
Tillotson JT-207 Performance Cylinder Head – Box Stock 196cc Clone
138190024 Tillotson JT-207 Box Stock Head - Packaged
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Tillotson JT-207 Performance Cylinder Head – Box Stock 196cc Clone

Part Number: 138190024
Online Price: $35.00
Tillotson JT-207 Cylinder Head for GX200 & 196cc Clone Engines
Availability: In Stock.

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Description

Tillotson JT-207 Cylinder Head – 196cc Box Stock Class Legal


Unlock the full potential of your 196cc racing engine with the Tillotson JT-207 Cylinder Head—a purpose-built performance upgrade developed by EC Carburetors to meet the strict demands of the Box Stock kart racing class. Also known by its factory code TIL-1, this head is engineered for consistent quality, better airflow, and superior durability over mass-produced alternatives.


Purpose-Built for Power & Consistency

Unlike factory clone heads designed for power equipment, the JT-207 is manufactured exclusively for racing, ensuring consistent casting quality and tighter performance tolerances. Many stock heads vary greatly due to worn molds and inconsistent quality control—issues you won't find here.


Technical Specifications:

  • Valve Size: 25mm Intake / 24mm Exhaust
  • Valve Stem Size: 5.5mm
  • Retainers: Accepts stock slip-on retainers (legal for Box Stock classes)
  • Casting Use: Also serves as the base for Tillotson 212R/RS and 225R/RS (with larger valves)
  • Material Improvements: Thicker port and fin areas reduce warping and increase porting potential
  • Port Design: Optimized for high velocity and airflow efficiency, both in restricted and open classes


Flow Bench Comparison (28" Water)

Flow tested by Young Engines using identical valves for a fair comparison:

Valve Lift

JT-207 (CFM)

JT-158 (CFM)

0.050"

15.9

15.9

0.100"

30.0

30.0

0.150"

43.5

42.6

0.200"

46.0

44.1

0.250"

47.0

46.0

0.300"

48.5

48.0

0.350"

50.5

48.5

Result: The JT-207 outperforms the JT-158—especially in the mid-lift range—where real-world acceleration and throttle response benefit the most.


Why Choose the JT-207 Head?

  1. Superior Casting Quality
    • Manufactured solely for kart racing—not for lawn equipment.
    • No guessing on casting codes or performance variation.
  2. Improved Performance Within the Rules
    • Designed to increase velocity and maintain port signal.
    • Legal for porting in open classes with minimal loss of velocity.
  3. Built to Last
    • Reinforced material between fins and ports for greater heat resistance, especially under high compression and advanced timing.


Racing Class Compliance

Fully legal in:

  • NKA (National Karting Alliance)
  • AKRA (American Kart Racing Association)
  • WKA (World Karting Association)


Ideal for:

  • Box Stock / Stock Appearing / Builder Prepared classes
  • 208cc Limited Modified & Open classes where durability and flow matter even more.

FAQ

1. What valve sizes does the JT-207 use?

The Tillotson JT-207 comes with 25mm intake and 24mm exhaust valves, using 5.5mm valve stems. It’s designed to accept stock slip-on retainers.


2. Is this head legal for AKRA or NKA classes?

Yes. The JT-207 is fully legal for AKRA, NKA, and WKA Box Stock and Builder Prepared classes.


3. How does it compare to the JT-158 head?

Flow bench tests show the JT-207 flows better across the entire lift range, especially in mid-lift zones where throttle response and power gains matter most.


4. Can I port this head for modified classes?

Absolutely. While it performs well in stock form, the JT-207 is port-friendly, thanks to reinforced casting around ports and fins. Perfect for 208cc limited modified or open classes.


5. Why is the JT-207 more consistent than stock clone heads?

Stock heads vary in performance due to worn or inconsistent casting molds. The JT-207 is purpose-cast for kart racing only, resulting in more predictable performance and flow quality.

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