Starting a Rebuilt Motorcycle Engine

starting a rebuilt motorcycle engine
This is another one of those hotly talked about and contested issues if you are a regular reader on motorcycle forums – the proper steps to take when starting a rebuilt motorcycle engine.  Or should we say restarting?  I never know.  Anyways…..

There is a range of answers out there that run the full spectrum from an exhaustive, overly cautious checklist to just pressing the button and seeing what happens.  You will come to find out neither is really all that wrong.

I figured this would be a good post since most of the time when you google “starting a rebuilt motorcycle engine,” you end up with a bunch of articles about engine break-in.

Now, don’t get me wrong.  The topic of engine break-in is equally and arguably more important, but that isn’t what this particular blog post is about.  The focus here is on the specific steps one should take before that first kick or press of the start button.

This article also assumes that the rebuilder has properly greased all vital engine components on rebuild/reassembly.  To the extent this step was missed or forgotten, I would definitely suggest a more cautious restart procedure with manual lubrication as described below.

The differences in methods really come down to what I will call “manual lubrication” vs. “no manual lubrication.”

Let’s start with “no manual lubrication.”

Proponents of this method state that if everything is properly rebuilt and greased, that engine oil will reach vital components within just a few seconds of restart.  Therefore, press the button, kick it, whatever – no special procedures required for starting a rebuilt motorcycle engine.  They aren’t wrong.

That said, there is absolutely nothing wrong with being more careful when starting a rebuilt motorcycle engine, which really equates to making sure that oil is traveling through the system, lubricating everything, and returning as it should.

I know that personally, after pouring my time and effort into a rebuild, it is sometimes nice to feel like you are taking additional precautions and not rushing the final steps before restart.

This article is a little specific to American bikes (i.e. the steps regarding checking for return oil), but the methods for manual lubrication are applicable to any bike.

So how do you manually lubricate the internal components before starting a rebuilt motorcycle engine?

There are a few methods, but for all methods make sure 1) the spark plugs are removed 2) fresh oil has been added, and if you have a Harley with a separate oil tank that the tank return line is disconnected.  Call these steps 1 to 3.

Now it comes time for turning the engine – maybe you already know a few methods for this.

First, you can put the bike in neutral and let the starter motor do the work with a two or three quick two or three second pushes of the starter button.  This is my least favorite method.

Second, you can put the bike in gear with the primary cover removed, grab a large socket and breaker bar, and turn the engine from inside the primary case.  This is an okay method, but I still prefer the method below the most.

With the rear wheel off the ground, put the bike in gear, and turn the rear wheel.  This will turn the engine (achieving the same result as method two) without opening the primary case again.

Call these three methods Step 4 for starting a rebuilt motorcycle engine.

Final step.  Turn the engine until oil comes out of the return oil line.  This is your indicator that oil has made it all the way through the engine and everything has been lubricated.

And that’s it.  Five steps to take prior to starting a rebuilt motorcycle engine.

Please forgive any typos as I wrote this blog post from my cell phone.

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