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Discussion Starter · #1 ·
Hello PBP members!

For the past 2 weeks i conducted a little experiment. I'm sure that you have all heard of how to coorectly break in a pocket bike but i have come to with some surprising results.

I bought 2 Giovanni pocket bikes from ebay and my plan was to "break in" the engine with the "proper" method, which is not hitting high RPMs.
Then i was going to use my method which was to "ride it like you stole it" (KINDA)

Lets get started.

For the first bike i did everything by the manual. I went through 4 tanks of gas and i didn't hit high RPMs at all. (As the guide stated). Of course i heat cycled the engine first before hitting the track.

My second bike i did things my way. I started the bike for the first time and let it idle for about 10 minutes to get the gas flowing. I then took it out to the track and brought 2 L of petrol with me. My goal was to hit different RPMS. what i would do was go WOT then once it hit max RPM i would drop it down to a more idle speed. i then would go around the track going all different speeds. Mostly 3/4 throttle. Then once i burned thru a tank i put in another litre then i drove it like i stole it.

You might ask why i broke it in at such high RPMS.
Inside the engine there is a piston, there is also a piston ring that needs to be "set" properly. If you dont drive the bike in high RPMs the piston ring will never really get enough pressure to "set.

OK OK one thing you shouldn't do is drive it at MAX RPM for longer then 3-4 seconds as the oil in the gas has not et lubricated the engine. after one tank of gas the engine should be all lubed up. then you can drive it "hard".

Never drive your bike slow to break it in. you will lose alot of possible engine speed. In short words, do little burts of speed randomly for atleast half a tank of gas.

One other thing that is important is to let the engine warm up!

ALWAYS let your engine warm up before you ride it. (idle it for 5 minutes)


So how can i prove this?

After i broke both bikes in i hit up my school race track. (not one for cars and bikes but for people running lol).

I have a TOMTOM gps that shows the speed you are going and i was getting about 35 KMPH on the engine that i broke in with the "proper" way. As for the "Drive it like you stole it" method i was getting 47 KMPH.

I spent over 5 hours testing this method doing over 90 runs for 300 Meters.

I then took apart the engine and looked inside the "proper" way had alot of gunk inside that built up during the "break in" period. As for the "DILYSI" (drive it like you stole it) method it was completly clean and looked great.

I used the EXACT same bikes. Exact same parts. Exact same oil to gas for break in and exact same tire pressure.

The only difference was how i broke it in.

So in other words guys... Drive it like you stole it! (KINDA)

Dont drive it to slow but dont drive it to fast for long periods of times.

Also just a random tip if anyone has hot exhaust problems.

On my blata B1 REP i had a Terrible exhaust problem it heated up so much that it would burn my ***. So what i did was get tin foil and wrap the pipe in it about 5 times, i then put a bunch under the seat and wrapped the gas tank. it helped TONS. try it :)
 

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Welcome to the Planet,very interesting read.
What was the gas/oil ratio you were using ?
 

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Wow, that's allot of testing, but as an automotive and diesel tech, I do not agree.

I bet if you broke them both in the exact same way, one would still be slower.

Tested before it leaves the factory, yup, a dab of gas, a pull of the starter, a rev of the engine with the rear wheel off the ground, quality control done.

no dyno's or anything like that...

While opening the engines, up in the head area, lots of oil is actually a bad thing, but we want to see some in the lower half, otherwise those bearings are going to fail sooner than the "Wet" ones.

I am interested to here about which one works better in a year from now.

Thanks for the post, I'm like you too, Believe nothing you hear and only half of what you see.
 

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Discussion Starter · #5 ·
Well the jist of it is simple. You want the piston rings to set nice and tight. if you don't allow them to sit tight during the break in period then you will lose alot of speed. mainly because all the pressure that pushes the piston up will escape around the sides. The reason some manuals tell you to drive it slow for the first 4 four tanks is because thats how long their warrantys last:p. like i said dont rev it till your engine starts smoking. but give it enough throttle to seal the rings.
 

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What was the gas/oil ratio you were using ?

Was it 25:1 , 32:1 or 40:1 ?
 

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To anyone who's considering following these "break in" instructions..I have to say I strongly recommend you don't. They seem more like "break" instructions. I've had countless 2 stroke engines on everything from pocket street bikes, pocket dirt bikes, pocket go carts, RC cars ect. and the only time I had a new engine fail shortly after purchasing it was when I didn't closely follow the break in instructions on a $600 Full Mod O'neil Brothers Racing motor in my HPI baja. I went right to full throttle after less than a tank of low RPM thinking it would be fine and I payed the price. My replacement motor from them (that was broken in exactly as instructed) is almost 2 years old and is still going strong.

You might not destroy your motor right away following these "break in" instructions but I guarantee the longevity of the motor will be greatly reduced.

I can see how it would seem like a good idea after only 2 weeks of testing but I'd really like to see how the motor is doing in 6 months, or a year if it's still running.
 

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Here is some "insider" information (off the top of my head so it's not going to be exact)


Dissimilar metals, the Nickle coating on the cylinder, the sometimes Chrome piston ring, etc, different metals do not like each other, we need to introduce them slowly, and toss lots of oil at them so they can get along.

The coating on the cylinder, well, the whole cylinder and piston grow and shrink, <--not joking! we want to grow and shrink them a little bit at a time, otherwise our cool "coatings" like to chip away!

Carburetors, they do not care, except for too much heat!

The clutch, the types of clutches / bells we use will do much better in the long run when slowly beaten to death, and not blasted with WOT right away, we need to heat cycle the glue, so it can cure cure cure!

If you guys want to hear more, say the words and I will do a multi-page write up ASE style, with pictures and everything.
 

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Nick is 100% correct. The coating on the cylindar is what failed on my O'neill Bros motor when I didn't break it in properly.
 

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Discussion Starter · #10 ·
i used this method on my blata replica about a year ago. engine still runs fine and the top speed is great :)
 

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i used this method on my blata replica about a year ago. engine still runs fine and the top speed is great :)
You are lucky! must be running lots of oil mixed with the gas maybe?

Every engine on earth should be broken-in based on the OEM's recommendations, why would they care, oh because it will cost them their company if they didn't, warranty!

They pay super crazy engineers (even crazier than me!) to spend 5 years at a time, trying every possible configuration, and each different method, and all different types of oil, etc.

As for the piston rings, here comes another solid bit of "privileged" info...

It's the exploding fuel mix above the piston (head-land area) that forces the piston ring down, which in turn forces it to open, so, it's a seal on demand setup, low idle (pressure) and they seal loose, and the opposite when a high load is applied.

Good questions, they are common issues, and many more than just you will *possibly* benefit from what we are discussing right now.

I call myself a newbie, but I'm not, and I am willing to share every single bit of information I am able to, for free, to the lovely users of this little forum!
 

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Discussion Starter · #12 ·
see your point of view is possible. but what you dont understand is that you lose engine speed. Everyone who uses the "easy" method doesn't know really how fast their bike can go because they never drove it in high RPM LOL.

im not trying to make you use this way but i just want to share my tests i conducted.

Also the main arguement about this is that the piston might be to big for the bore. But what you dont realize is either way its gonna get fitted correctly. the only difference would be the ring seal.

i used 32:1 for break in then after that i used 50:1 to test.
 

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Discussion Starter · #13 ·
Quick steps for the hard method:

1- idle the bike for 10 minutes.
2- let it cool down.
3- idle the bike for 10 minutes.
4- let it cool down.
5- idle the bike for 10 minutes. (WARM UP)
6- take it for a drive start off going just where the clutch engages. (my bikes clutch engages at 8300RPM.) (yes its a racing bike)
7- start driving the bike a little bit harder make sure you hit different RPMS. dont go WOT for longer then 5 seconds. make sure you do go WOT for atleast 3 seconds though.
8- let bike cool down
9- repeat step 6-7 two more times.

the reason for the heat cycle at the start is to listen to the motor and see if it has a nice sound to it (e.g steady pace)

It also gets the fuel running for the first time
 

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I totally see what you are saying, but, it's not common "race team" practice, you've got to give the older guys a little bit of credit some of the time...

You would never lose any top speed from a proper break-in, that part is 100% myth, but with a single cylinder, every little thing is noticeable, so those two bikes, would have ridden different no matter what you did, just make sure and ride the fastest one, then it's easier to win!

We bought two C1's from the same dealer at the same time, that came in on the same shipment, and they we're totally different, performance wise.

And I'm not missing any of your points, I'm only sharing my own insider information. been wrenching on these since 2005, almost done with two tech certs, for automotive and diesel technology, some of the info I posted cost $100's just for the books, not counting the school fees, and the time it took to READ and ask my 10,000,000 questions, (sorry again Sergio!) :p
 

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Discussion Starter · #15 ·
From mototune What's The Best Way To Break-In A New Engine ??
The Short Answer: Run it Hard !

Why ??
Nowadays, the piston ring seal is really what the break in process is all about. Contrary to popular belief, piston rings don't seal the combustion pressure by spring tension. Ring tension is necessary only to "scrape" the oil to prevent it from entering the combustion chamber.

If you think about it, the ring exerts maybe 5-10 lbs of spring tension against the cylinder wall ...
How can such a small amount of spring tension seal against thousands of
PSI (Pounds Per Square Inch) of combustion pressure ??
Of course it can't.

How Do Rings Seal Against Tremendous Combustion Pressure ??

From the actual gas pressure itself !! It passes over the top of the ring, and gets behind it to force it outward against the cylinder wall. The problem is that new rings are far from perfect and they must be worn in quite a bit in order to completely seal all the way around the bore. If the gas pressure is strong enough during the engine's first miles of operation (open that throttle !!!), then the entire ring will wear into
the cylinder surface, to seal the combustion pressure as well as possible.


The Problem With "Easy Break In" ...
The honed crosshatch pattern in the cylinder bore acts like a file to allow the rings to wear. The rings quickly wear down the "peaks" of this roughness, regardless of how hard the engine is run.

There's a very small window of opportunity to get the rings to seal really well ... the first 20 miles !!

If the rings aren't forced against the walls soon enough, they'll use up the roughness before they fully seat. Once that happens there is no solution but to re hone the cylinders, install new rings and start over again.
 

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Every time I burn a tank of fuel during my break-in process I do a compression test...I also do one before start-up....

If the compression doesnt get higher than the original test numbers then I know somethings not going right and do a quick tear down to see why but so far every engine Ive built has had the compression numbers raise 2-3 psi every tankful.......Except one...............

This piston came from an engine I broke in using a similar method to this threads author...If you know how to read a piston you can notice the piston has alot of compression blow-by because hammering on the engine with a tight cylinder turned the cheapo chinese rings to rubber.......The rings were so scorched they broke in half when being removed.......The carbon build-up on the sides should of been on the piston top.........







Listening to the racers break-in methods can be deceiving especially when race prepped engined are honed a lil looser in the cylinder wall to piston tolerances with chromoly rings and floating pins as a pre-break-in process so you can actually hammer a brand new build from the first second its started....Beleive me Ive built racing engines for Pro-Mod NMCA for 17 years up until 3 years ago...

Racing engines dont last very long.................My 133mph IAME methanol powered Outlaw race kart racing engine has a 220 minute lifespan before needing a rebuild;-any longer and you risk it going BOOM!......................I used to have 2 extra backup engines when I raced this in the 80's...........



 

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Discussion Starter · #17 ·
that thing looks pretty fun lol, i did the same thing after my last year race season. i agree with you 100% that you need to rebuild the engine. e.g new rings lightly sand down the piston etc.

but i truly believe that the instructions in the guides that state do now hit open throttle until after 4 full gas tanks is truly overkill.
 

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Discussion Starter · #18 ·
p.s just by looking at your pistons i can tell that you went WOT for quite some time during break in period
 

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Hmmm, are we forgetting this is bottom barrel Chinese "Quality" Japan / America etc is one thing, a China made pocket bike is not even in the same swimming pool!

No wonder pocket bikes have no warranty!

But, since it's not already broken, I doubt you messed anything up.

:):thumbsup:
 
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