Break-In a Rebuilt Engine

Any new or rebuilt motorcycle engine will need to go through a break-in period to make sure it reaches its full power potential and runs smoothly.

Your manufacturer’s shop manual may have a specific break-in procedure, which can be helpful.

The break-in period allows new parts to move together as they should. If you’ve replaced the piston rings, a proper break in will allow the rings to seal properly and avoid having the cylinder walls glaze over.

You’ve got to be careful not to break-in your new engine too easily or too hard. If you go too easy on the bike, the cylinder walls are bound to glaze over and your piston rings won’t seal properly. If you go too hard breaking in your rebuilt engine, you run the risk of it overheating and seizing.

Motorcycle Engine Break-in Routine

During the break-in period, which typically lasts for the first 1,000 miles, you can follow this drill to help your rings seat without overheating the engine:

  • Find a long, straight road.
  • Get into 2nd or 3rd gear and accelerate at WOT (wide open throttle) to about 1,000 or 2,000 RPMs below the redline.
  • Shut the throttle and coast in gear at about 2,000 RPM.
  • Repeat without letting the engine get too hot.

If you’re driving your rebuilt engine on the freeway, try to vary the RPMs and throttle position every few miles.

Oil Changes During Engine Break-in Periods

During your break-in period, you’ll also want to change your oil more frequently. Some recommend changing the oil and oil filter on your motorcycle at the following intervals:

  • 150-200 miles.
  • 300 miles.
  • 600 miles.
  • After 1,000 to 1,200 miles.

Changing the oil on a rebuilt engine is necessary to get any metal out as parts find their position and to ensure the oil stays as fresh as it can as the new parts are breaking in.


Scroll to Top