Note: This is a specialty product and is not currently available for purchase online. Please call Duncan Racing International and a DRI staff member will assist you by collecting the required specifications and placing your order. Thank you.

NOTE: Vortex Ignitions has discontinued manufacturing their INTERCEPTOR line of piggy back fuel controllers to focus all their resources on manufacturing their standalone X10 ECU (Engine Controller Units). Regarding INTERCEPTOR references on DRI website. DRI would recommend using a Vortex X10 ECU in lieu of using the now discontinued Interceptor. Please call Duncan Racing Technical Support 619-258-6307 for more information.

With today's modern ATV 4-Stroke engines, making additional Horsepower is no easy task...This makes it critical that Engine Tuners have the Experience, Knowledge and Equipment to do the job properly.

Duncan Racing International's HP4 Valve Train Kit is designed to give you the utmost in performance and reliability by using the most advanced equipment and techniques in the industry. All porting work is performed by our master technician and valve seat cutting is done on our in-house SERDI valve grinding machine.

PURCHASE OPTIONS

DRI HP4 Kit without Porting
#DR-170K $895.00

INCLUDES: Hardfaced camshaft (see options below), HD Valve springs, 4 shortened guides, 4-piece Big valve kit (2 IN, 2 EX)
* This kit does not include DR porting and SERDI Valve seat cut
**Kit must be installed by a trained professional
*** Cam Core required or pay $185 core charge

HP4 Kit with DRI Porting & SERDI Valve Seat Machining
#DR-170KP $1395.00
INCLUDES: DR Porting, SERDI Valve Seat cut, Hard faced camshaft (see options below), HD Valve springs, 4 HP guides, 4-piece Big valve kit (2 IN,2 EX) * Head will be reassembled by DRI

PERFORMANCE GAIN: up to 5 HP *Results vary depending on camshaft profile and piston compression. *Notes: **Kit must be installed by a trained professional

CORES REQUIRED: Head, Cam NOTE Customer Must Supply stock head and cam core in Good Condition or pay Core Charge Listed Below

NEW CORE PRICING: Head $561.00 Camshafts $185.00 8-Valve Cotters $30.00

VALVE OPTIONS: DR recommends using Big Valves +1mm Intake & Exhaust for short course/recreational use Stock Size Valves for Endurance applications (Dakar/Baja 1000 type races)
* DR also uses a modified steel guide in these endurance heads

DELIVERY TIME: 2-4 weeks

CAMSHAFT OPTIONS
#170-X92 (Endurance racing)
#170-X94 (Midrange)
#170-X90 (Race Cam/Mid/Top Power)

ADDITIONAL HONDA 700XX ENGINE NOTES; IT IS IMPERATIVE TO THE RELIABILITY OF THE HONDA 700XX THAT STOCK COMPONENTS LIKE CRANKSHAFT, MAIN BEARING CAM CHAIN AND ALL ASSOCIATED PARTS ARE KEPT IN TOP CONDITION. IF THESE PARTS ARE WORN OR DAMAGED THE RELIABILITY OF THE 700XX WILL BE SEVERELY COMPROMISED

HP4 KIT FEATURES
In-House Cylinder Head Porting* (by Master Technician)
*Valve guides are removed during porting process to allow for greater port reconfiguration

Port Design Modifications Aided by In-House Flow Bench Testing and Computerized Port Mapping Software

Precision Valve Seat Machining and Reconfiguration*
*DRI uses in-house SERDI Valve Seat Cutting Machine used by F1, CART and NASCAR.

Big Valve Kits (Stainless Steel or Titanium)

Heavy Duty Valve Spring Kits*
*With Titanium Retainers, Mandatory with High Performance Valve Trains

AMPCO 45 Shortened Valve Guides

Camshafts of the Highest Quality Made in the USA

All Head Work Done In-House for Reasonable Turnaround Delivery Time.

Customers Can Send In their Head for Modification or DRI Carries New OEM Heads.

HORSEPOWER
HP4 Kits with porting offer gains up to 5 HP*.
*Results vary depending on camshaft profile and piston compression

PIPE and IGNITION
For maximum performance, it is highly recommended to use a Fat Boy 4 Complete Exhaust and Vortex Interceptor with all HP4 Kits.

IMPORTANT NOTE When installing a high performance camshaft it is the responsibility of the engine assembler to check and confirm that the piston to valve clearance is adequate. Minimum clearance is .060" from valve to piston at peak lift. Tolerances can and will vary from engine to engine. There is no substitute for checking that these tolerances are correct. This is especially critical when mixing camshaft and pistons from different engine builders. One of the correct and easiest ways of checking this is by using the "claying the piston dome" method.
Call DRI or consult a professional technician