Engine Builds
At Def-Racing, we customize our engine builds to fit your budget, performance needs, and durability requirements. The following options are designed to help you understand the performance levels and costs associated with each build. If you have specific needs that aren’t addressed here, please don’t hesitate to contact us.
Professional AMA Build
Key Features:
- Stronger connecting rods
- CNC-ported heads
- Our unique port designs will often utilize epoxy in the intake port, improving engine response and power compared to conventional methods
- Moldstar90 valve seats and CNC valve jobs
- Custom valve guides and proprietary titanium valves
- Stiffer valve springs
- High compression pistons
- Aftermarket electronics (ECUs, dual injection systems)
Models:
Modern 4-Stroke | 250cc – 450cc
Turn-Around Time:
- 3-6 weeks
Engine Durability Limits Before Next Service or Rebuild:
- 10-20 hours (varies by rider, conditions, and maintenance)
Typical Engine Specs
- 15-25% Power Increase
- Race fuel only (VP, ETS, Renegade, or better)
- Compression Ratio: 250cc = 15.5:1+ | 450cc = 13.5:1+
- Crank Works / CP Carrillo rod or equivalent
- Dynamic racing piston with DLC coated pin
- Dynamic custom head porting, valve seats, and guides
- Dynamic custom camshafts and valves
- Manual cam chain tensioner
- ASF/ISF/REM superfinishing of internals
- Aftermarket ECU (Vortex, GET, or AIM) with custom mapping (Dyno tuning available and recommended by us or a reputable tuner)
- Assembled with OEM or superior gaskets, seals, and bearings
Average Cost w/Parts & Labor:
$3,500 – $10,000
Amateur AMA Build
In the amateur motocross world, there are a never-ending number of classes to compete in with varying rules. We offer stock or modified race engines at various levels to fit the rules per your sanctioning body. These are performance and reliability-oriented race engines built for all class levels… A, B, C and D classes.
Models:
- Modern 4-Stroke | 250cc -450cc
Turn-Around Time:
- 2-4 weeks
Engine Durability Limits Before Next Service or Rebuild:
- 20-40 Hours – varies by rider, conditions and maintenance
Typical Engine Specs:
- 0-20% Power Increase
- Pump Fuel & Race Fuel Mapping Available
- Higher Compression Piston
- Stock or Ported Head
- Stiffer Valve Springs
- Assembled with OEM or better than OEM gaskets, seals and bearings
- Stock and Aftermarket ECU Remapping
Average Cost w/Parts & Labor:
- $2,000 – $3,500
Drag Race “Grudge” Build
This is a very purpose-built engine. With only 1 thing in mind “MAXIMUM POWER”. For many of these engines we design and manufacture our own cams, pistons, valves, fuel and intake systems. We can essentially build any motocross or ATV engine into a drag race specialty. We do have a few very common build packages from the CRF450R and YZ450F, but we do and can build just about anything you would like.
Models:
- Modern 4-Stroke | 450cc-600cc
Turn-Around Time:
- 4-8 weeks
Engine Durability Limits Before Next Service or Rebuild:
- 5-10 Hours – varies by fuel specification, conditions and maintenance
Average Cost w/Parts & Labor:
- $5000 – $15,000
Typical Engine Specs:
- 30-75% Power Increase
- VP: Pro6, MR12, M1, M5, 5050 Meth-Nitro / ETS MX18 & MX21
- Low and High Compression Piston depending on fuel type
- Crank Works or CP Carrillo Rod
- CP or JE Piston
- Large Camshafts, Valve Spring Kit, Larger Valves, Large Port and sometimes with a spigot. Larger Throttle Bodies, Custom Injectors Size, Override Trans. etc
- Dual Injector Systems
- Aftermarket ECU: Vortex, GET or AIM Electronics w/Custom Mapping (Dyno Tuning Available)
- ARP or KPMI Head Studs
- Assembled with Cometic Head gaskets and generally OEM gaskets and seal everywhere else.
Enthusiast Build & Vintage Build
These engines are built with a combination of high-quality aftermarket and OEM parts. Typically equipped with tasteful modifications and built to last and not giving you any trouble on the track or trail. Specs and power levels are heavily dependent on customer budget. Runs on pump or race fuel fuel, mild compression and PLENTY of reliability.
Models:
- 2-Stroke | 50cc – 500cc
- 4-Stroke | 150cc – 450cc
Turn-Around Time:
- 2-6 weeks
Engine Durability Limits Before Next Service or Rebuild:
- 40-100 Hours – varies by rider, conditions and maintenance
Typical Engine Specs:
- 0-10% Power Increase
- Pump Fuel or Race Fuel
- Stock or slightly higher compression piston
- Assembled with OEM or better than OEM gaskets, seals and bearings
Average Cost w/Parts & Labor:
- $1,500 – $2,500
Complete Engine Lease Programs
Our complete engine lease programs provide riders and teams with high-performance engines without the long-term commitment to creating an in-house engine program for yourself. This service allows access to championship-caliber engines for races, ensuring you have the reliability and speed you need on the track. Turn key race engines at your disposal.
Consulting
With years of industry experience, we offer expert consulting services for engine design and performance optimization. Whether you’re a privateer or a professional team, our insights can help you achieve your performance goals through targeted strategies and solutions.
Engineering and Design Support
From concept to execution, our engineering and design support services cater to custom projects. Whether you’re developing a new engine or modifying an existing one, we work closely with you to bring your vision to life with innovative design solutions.
services
Vapor honing is also commonly known as wet blasting, liquid honing, vapor blasting, dustless blasting, or slurry mix blasting.
The multi-size grit/abrasive media (usually glass bead) is mixed with water and compressed air to blend before being propelled through a blast nozzle. This process is known as slurry blasting or vapor honing.
u200bContact us today to get your parts vapor honed!
