Brand New moped engine break in schedule

DaveinNaples /

Saw an article in this forum a few months ago about the proper way to break in a new 2 stroke engine, but alas.........can't find it again.

Anybody know where I can get a copy of that expert bit of information?


Re: Brand New moped engine break in schedule

There is more than one way to break in a new engine.

1. follow the manufacturers recommendations and drive slow until you have about 650 miles on it, or until you are so sick of that you sell it and buy an old one. Or.

2. Drive easy for the first 50 miles, then gradually increase your speed for a few minutes every day. Run it up to top speed for a few seconds and slow down for a few minutes. They main thing is don't let it get too hot. When a piston and cylinder are new they tend to warp if too hot, after it has cured this doesn't happen. Short trips, 5 to 10 miles, with a complete cool down in between speeds up the curing process a great deal. Above all, increase the oil ratio in the gas by about 20% for the first few hundred miles. If you follow the second pattern you will be all broken in by 300 miles. Ken

Re: Brand New moped engine break in

I don't know if this is the one you are talking about.

But I did a search and got lucky... here is one I posted a while ago.


Break In


During break in you are mostly trying to let the piston expand and form to the cylinder.

Run it at about half throttle for about 10 minutes... then let it cool to the touch.

Do that about 3 times.

Then go to about 3/4 throttle for 10 minutes at a time... again let it cool to the touch.

Do that 3 times.

Now you can go to full throttle... but only for short bursts.... like 30 seconds... then back off and ride at 3/4 throttle for 5 minutes or so before going full throttle again for a short burst.

Do that 3 times for 10 minutes at a time.. again..while letting it cool between rides.

So you've run it 9 times now.

Now you should have 90 minutes on it.

You no longer have to keep shutting it off and letting it cool.

But still don't run it wide open for long periods... back off and let it cool as you ride gently.

Once you reach 50 miles or so you can start going full throttle for longer times.

Once you reach 100 miles you should be able to run it as hard as you want as long as you want.

(I think some manuals say to go 300 miles before flogging it... If you want to wait that long... go ahead... but modern high performance 2 strokes don't need anywhere near that much... I think 100 is plenty)

You should never rev up any engine (old or new) to high RPM till it has warmed up.

Re: Brand New moped engine break in

Fred. That is EXCELLENT!!!!!! Doug D

Re: Brand New moped engine break in

DaveinNaples /

Yeah, that was the one, thanks Fred.

Re: Brand New moped engine break in schedule

daveinnaples /

Thanks Ken, I'm going to follow somewhere between yours and Freds recommendations.

Re: Brand New moped engine break in

All I know is that when I bought my moped, the manual said not to go over 18mph for the 1st 300 miles, which was really hard to do! But when I posted the same question as yours at this forum, everyone who responded said I should follow what the manufacturer recommends.

Re: Brand New moped engine break in

Hi Peggy! What the manufacturer is trying to avoid by saying that is the tendency of a lot of impatient people to run at higher than 3/4 throttle and especially up hills or overloading the engine.The new components build up heat when you push the moped to it's limits right out of the box.I sure can't improve on what Fred said except to say don't rev your engine on the stand,except for very short bursts and not wide open.So break-in is a skill which involves knowing if your straining your engine or if it's heating up too much and that might be why the Gurus were over -cautious.People are so different you know.I'm the kind of guy who could hum along the first 300 miles and just enjoy the scenery traveling slow,only going up to 25 down the hills.The guys I work with, (we have to follow written procedures VERBATIM,which means: read a step,then do a step), tell me they wish they had my patience,and it near kills them to do a job in this manner.ANYWAY,sorry if I sided with the overkill language of the manufacturer.

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