Engine break in process

monturacer3 · Nov 1, 2014

My phone won't let me search through the threads for tips on engine break in process, so in advance, sorry if this is a re-post.

Last week I ordered a 66cc kit from Dax and while I'm waiting to get it, I might as well ask, how should I break in the engine? I think I read somewhere that I should use between a 20-30:1 oil and gas mixture, but I'd like some more info on this. Such as how many miles should I break it in for or how many tanks of gas should I go through before lowering the oil content. Any info helps. Super excited to start building my bike!

Slogger · Nov 1, 2014

There are as many opinions about break in as there are members here..

My new DAX engine gets 25/1 Valvoline 2 stroke oil in its premix, Duane told me they recommend running 25/1 as the standard mix, not just for break in.
My bike ran very rich at first, but dropping the needle and putting in a .66mm jet from SBP got that straightened out and it's running well and getting stronger each ride now. This town is at 975 feet above sea level.

I vary the throttle and take it easy 95% of the ride, and after it's warmed up I might give it full throttle for a few seconds, just to see if there's any improvement.
Then right back to half to 3/4 throttle. Mine is doing real well, but cold weather here is cramping my ridin time all ready.
Good luck to ya, check your mounting bolts regularly, don't forget to check the exhaust mounting nuts, too!
Heck, check everything.

BobbyT · Nov 1, 2014

Welcome,
As mentioned you will get many different answers to this ouestion. I run the first tank at 32 to 1 and very my speed. After that I use 40 to 1. Make shure to check bolts, nuts and chain often during break in. Do as much research as you can. Have fun!

Venice Motor Bikes · Nov 1, 2014

I recommend using 24:1 for the first two gallons, then switch to 32:1 for the rest of the engines life.
40:1 is also acceptable after break in, but I prefer a little more oil in my engines, (just to be safe).

Another thing to check are the center bolts that hold on the small chain sprocket & the small gear on the clutch side; those often aren't torqued properly from the factory.

monturacer3 · Nov 1, 2014

Thanks everyone! I think I'll try 25:1 to start out with for the first couple tanks and just experiment with some other mixtures. What fuel should I run too by the way?

Venice Motor Bikes · Nov 2, 2014

I use 91 octane in all my bikes. These engines have such low compression that it shouldn't matter, (but it does)!

Also, don't use synthetic oil for the break in!! (it works too well & the engine won't break in propperly). :/

monturacer3 · Nov 2, 2014

Venice Motor Bikes said:
Also, don't use synthetic oil for the break in!! (it works too well & the engine won't break in propperly). :/

Should I use non-synthetic for the life of the engine too?

Slogger · Nov 3, 2014

monturacer3 said:
Should I use non-synthetic for the life of the engine too?

I think synthetic is a fine idea, after the break in is complete, that is. It's too slippery for break in.

I have a question about mine- I was ridin today (nice out, woohoo) and after a few miles I did a top speed check, hit 28.8. A vibration starts in at about 28. ? This is at 5300 rpm. (It's got a tall gear and a fat rider)
After a couple more miles, did it again and only hit 26.5, and the speed begins to sag off if you keep holding it wide open.
Would this be a sign of being too lean, too rich, or just not broken in yet?

Thanks for any responses in advance.
drn2

monturacer3 · Nov 3, 2014

Slogger, even though I'm new here, I think the problem you are having is the carb being too lean. I've had that same issue happen to me multiple times on my 50cc pitbike and I rebuilt and re-tuned the carb and it performed a lot better. I would suggest a carburetor rebuild and see how that goes for you.

Slogger · Nov 3, 2014

Thanks, Monturacer3
I'll go take a look at the plug. The carb itself is ok, I've been changing the jet and float height as the bike breaks in, I suspect it needs some more tampering on my part.. Or maybe less.
haha this is fun!

Edit: The plug was a dark tan with a hint of an oil sheen on it.
I'm thinking it might be time to go to a 32/1 mix to richen the fuel /air mix a bit and improve the oily plug syndrome at the same time. I think the plug gets oily on longer runs (at half 3/4 throttle) due to the 25/1 and the low load, easy running. The spark weakens and you lose a little hp.
The next gallon will only have 4 oz of Valvoline 2 stroke oil.

Motor awesomeness · Nov 3, 2014

Use 20:1 or I heard some people use 16:1 oil:gas ratio for the first tank or two and then after the first tank or two, use whatever the manufacturer recommends

MotorBicycleRacing · Nov 4, 2014

I just talked to the tech info at Maxima in San Diego who said that 8oz of oil is Crazy.

They recommend breaking in and running at 32 to 1 ratio.

There is No need to add extra oil.

The first 20 minutes of running after first start are crucial to seating the rings.
Full throttle once your motor is warmed up to seat your rings on that chrome bore for good compression.

monturacer3 · Nov 4, 2014

Well Dax says to run 20:1 non-synthetic for break in. And that seems a bit high. I wouldnt want to screw up a brand new engine by running the wrong mixture. So 32:1 for a couple tanks for break in is fine?

monturacer3 · Nov 4, 2014

And I've been waiting for That's Dax to ship out my kit for almost 2 weeks now. Is that normal for them?

crassius · Nov 5, 2014

MotorBicycleRacing said:
I just talked to the tech info at Maxima in San Diego who said that 8oz of oil is Crazy.

They recommend breaking in and running at 32 to 1 ratio.

There is No need to add extra oil.

The first 20 minutes of running after first start are crucial to seating the rings.
Full throttle once your motor is warmed up to seat your rings on that chrome bore for good compression.

well, that answers the first two of philosophy's three most important questions:
Who says?
Who's he?
How does he know?

we'll await an answer to the third (hopefully in the form of "running 1000 identical engines each way, one way yeilded engines that ran x number of years longer than those done the other way"

2door · Nov 5, 2014

crassius said:
well, that answers the first two of philosophy's three most important questions:
Who says?
Who's he?
How does he know?

we'll await an answer to the third (hopefully in the form of "running 1000 identical engines each way, one way yeilded engines that ran x number of years longer than those done the other way"

I always prefer "They Say". Of course I've often questioned who 'They' are and I've come up with a mental image at least.

Three robed and hooded figures sitting at a rough hewn table in a torch lit cave with quill pens and scrolls and writing what will someday be quoted as "They Say". The scrolls get passed around and whenever a person needs proof of something they quote from the scroll. "They say, that you can't break an engine in on syn oil".
Hmmmmm.

Tom

Davezilla · Nov 11, 2014

Realistically, there are more ways to break in these engines than there are members in this forum... and they all work as long as it's your idea and you throw in the "this tech rep for so and so engines says do it this way"

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Engine break in process

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Venice Motor Bikes

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