Engine Break In - 97-01 Honda CR250 Top End Service - Part 15

Jan 26, 2019

1997-2001 Honda CR250 – Top End Rebuild – Part 15: Engine Break In

How To Break In The Engine On Your 97-01 Honda CR250

The Parts You Will Need

Tool & Parts
Oil
Coolant
Fresh Spark Plug
Clean Filter
Fresh Gas
(Master Tools & Parts List Below)

You should take at least an hour for engine break-in on your CR250. This might seem like overkill but I would rather lock up at five mph in my driveway than 30 mph 5 miles from my truck.

Before you do anything, refill your oil and coolant. Make sure to use a clean filter, spark plug, and freshly mixed gas.

This is also a good opportunity to catch other issues. For example, I spun my bike around, and it suddenly died. Upon further testing, I found a fuel flow issue that was not bad enough to kill my bike while riding, but just enough to cut off fuel when bouncing around.

During the break-in, always bring your environment into consideration.

Temperatures During Break-In

I rebuilt my bike in the winter, which is pretty common, and I’m breaking in my bike outside, which is also pretty common.

My shop is between 60 and 75 degrees, and outside is 20 degrees. The transition from warm to cold quickly will affect everything on a dirt bike. Aluminum, seals, and oil will all change, albeit not much, but more than I want in this situation.

This means I need to minimize the time between the shop and starting up in the cold.

Break-In Surfaces

Take note of what surface you are on.

The ideal surface is a dry gravel road because if you grab too much throttle, your tire with spin enough to avoid a sudden load on the engine. And if you lock up, you will, hopefully, slide to a stop.

The pavement is a good break-in surface because you have more control over your bike, but you lack the safety net of a loose surface.

The worst surface for a break-in is snow, which is all I have. Break-ins in the snow are always fun because you have to keep momentum while trying not to.

But no matter the surface, make sure it’s as flat as possible.

Engine Break-In

When braking in your engine, you want to avoid any sudden load, over-revving and lugging.

Kick your bike over inside first to make sure it actually starts, and there are no obvious problems.

Take your bike outside and start it.
Let your bike idle for a two count, then give it some throttle.
Repeat this process until your bike is warmed up.

You can adjust your idle later if you need to, but for now, it’s important NOT to let your RPMs stay steady.

Get a running start and click into first gear, then ride your dirt bike for about 10 minutes with varying throttle input WITHOUT going over ¼ throttle.

Let your bike rest for 5 minutes while checking gaskets and seals, then repeat the engine break-in process five more times, increasing throttle input by a ¼ turn every second run.