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Writer's picturePJT Powersports Repair

Break-In Procedure: For ATV And Dirt Bikes With Four Stroke Engines.

Updated: Sep 15, 2023

Whether you've just invested in a brand-new ATV or dirt bike, or you've recently had your engine rebuilt, one critical step remains before hitting the track or trails at full throttle. At PJT Powersports Repair, we recommend that all engines undergo a proper break-in procedure. Here are the steps that PJT uses to ensure an effective engine break-in.


Over the years, PJT has discovered this particular engine break-in procedure yields the most success for ATV'S and dirt bike's with four stroke engines. Here is the procedure we follow and recommend you do the same.


Preparation


Before starting the break-in, it's good practice to place your machine on level ground in a well-ventilated area. For the first two startups, leave your radiator cap off. This will allow the cooling system to purge—also known as bleeding—the air out of the system. Be sure to consult your owner’s manual to see if your machine has a specific procedure for purging the cooling system.


The Break-In Procedure


There are two parts to the break-in procedure:


Part One: Mate Components and Heat Cycling


The first part focuses on the need for new parts—whether sliding or rotating against one another to mate together. Some components, like valves, valve spring, etc. Also need some time to break in before being subjected to full load and power.


To achieve this, start the engine and let it warm up to its operating temperature, usually taking about 3-5 minutes. A good way to gauge this is to feel the heat radiating from the radiator be careful not to touch it and burn yourself. Keep the engine idling with NO abrupt throttle movements at all just Idle. If the engine makes any odd noises, shut it off immediately and identify the problem; do not proceed with the break-in. After 5-10 minutes, turn off the engine and let it cool completely, which usually takes 25-45 minutes. This warming and cooling process is often referred to as a "heat cycle."


Part Two: Achieving Good Ring Sealing


The second part of the break-in procedure emphasizes ring sealing, which is crucial for optimal engine performance. The rings must be exposed to pressure that forces them against the cylinder wall. For this, you'll ride the bike and gradually put the engine under load.



The Steps

  1. Step One: Initial startup Run the engine at idle until it reaches operating temperature (3-5 minutes). Shut it off and let it cool down (25-45 minutes).

  2. Step Two: Similar to the initial step but allow for light throttle blips during the 8-10 minute runtime. Let it cool (25-45 minutes), Chang oil only if you have a complete engine rebuild. If you only replaced your piston, you will change your oil at the end of break-in procedure.

  3. Step Three: Warm the engine for 3 minutes. Ride in the first two or three gears, varying the RPM but not exceeding half throttle. After 10 minutes of riding, let it cool completely.

  4. Step Four: Warm the engine for 2-3 minutes. Ride with the throttle up to three-quarters open for 10-12 minutes, shifting gears and varying the RPM. Let it cool.

  5. Step Five: Repeat Steps Three and Four, but this time you can use full throttle and hard accelerations through all gears. Avoid constant throttle positions and lugging the engine. Ride for 10-12 minutes, let it cool.

Congratulations, you've completed the break-in procedure! The final step is to change your oil and oil filter. Inspect the machine to ensure everything is tight and there are no leaks.


Oil Selection


One last point to address is the choice of engine oil for the break-in. Some suggest using specific mineral or synthetic oils designed for break-in. However, we recommend using your regular oil or whatever the factory specifies. Using specialized break-in oils may do more harm than good. If you've assembled your engine correctly, you should have already applied assembly lube or oil to all critical areas.


Summary


To summarize, the PJT Powersports Repair break-in procedure involves a series of startups, warm-ups, rides, and cool-downs to ensure your engine's longevity and optimal performance.


Congratulations on completing your engine break-in. We hope you found this guide helpful.


Thank you for reading.

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