Break-in Tips: 4-Stroke Engine

Here’s a shortened/paraphrased outline for breaking in a four-stroke ATV engine, according to Toby Reed of Moto-Xperts, engine builder for GNCC team Ballance Racing Yamaha. Reed used to answer the “Wrench This” section of ATV Sport magazine and has grown into a premier engine-builder in the ATV industry.

The engine is back in the chassis.

Tips prior to starting the ATV’s engine:

1. Install engine in chassis
2. Fill engine with fluids
3. Reed recommends you remove, clean and reinstall the carburetor (if non EFI)
4. Moto-Xperts suggests you do the same with the quad’s fuel tank (remove, clean and reinstall, then add fresh fuel)
5. Remove and clean the airbox assembly.
6. Clean and/or replace the air filter

Remove, clean and install airbox with new or cleaned filter.

Starting the 4-stroke ATV engine

• Check to see if engine oil flows to the top end (valve train). Do this by cranking it five to 10 times with the spark plug cap off. Once oil is circulated move on to break-in procedure.

• PART I (3 idle periods, 3 cool-down periods)

1. IDLE: Start engine and let idle to simulate Tiding-type conditions without a load on powerplant.  Have fan blowing on engine. Let it idle for 10 minutes.
2. COOL DOWN: Shut off engine after 10 minutes of running. Let it cool down for at least 30 minutes while fan blows on it.
3. IDLE: Repeat No. 1
4. COOL DOWN: Repeat No. 2
5. IDLE: Repeat No. 1
6. COOL DOWN: Repeat No. 2

• PART II (6 riding periods, 6 cool-down periods)

1. RIDE: Ride machine at 50 percent of your normal pace for 10 minutes. Vary the RPM range and don’t strain the engine during this step.
2. COOL DOWN: Another 30 minutes of complete rest for the engine.
3. RIDE: Go for 10 minutes at 60 percent of your normal pace. Vary RPM.
4. COOL DOWN: Rest for at least 30 minutes more.
5. RIDE: Ride and vary RPM for 10 minutes at 70 percent!
6. COOL DOWN: Let the quad/engine rest for at least another 30 minutes.
7. RIDE: This time, go 80 percent for 10 minutes, while varying RPM.
8. COOL DOWN: At least another 30 minutes more of rest for the engine.
9. RIDE: Ride for 10 minutes, again, at 90 percent. Vary RPM.
10. COOL DOWN: Turn off machine at each cool down. Another 30 minutes or more of rest is suggested.
11. RIDE: Ride at normal speed/pace, but vary RPM and keep it to 10 minutes!
12. COOL DOWN: Finally, let it cool for at least 3o minutes
13. Break-in should be completed (aside from checks; below)

Other Break-in Tips:

• Re-examine carb settings/jetting.
• Give your quad a complete once over/safety check
• Don’t use paddle tires
• Ride in open area (Read: not sand, MX tracks, mud, hills, challenging terrain, etc.)
• Double check all fluids
  

  Check the ATV exhaust for fitment after finalizing break-in and prior to official first ride.

• Check chassis and hardware bolts (especially on parts removed)
• Examine all fluid lines for leaks/kinks, etc.
• Inspect exhaust for fitment
• Check valve clearance (approx. 5 hours of initial running time)
• Inspect chains (cam chain tension and drive chain).

Contact:

Ph:(765)230-0514