Engine Break in time

[ndimatteo]

Hi guy's, I'm new to the world of motors and putting motor's on bikes ... I got my bike motor on and running well in a few hours, now it's tweaking time!! What i really want to know is how i should be operating the motor in it's beginning stages of life. Can i run at full throttle, if so how long? If not how long should i wait? Any information on the break in time of a 2 stroke motor would be helpful!!

Thanks all ...

 

[GearNut]

Do not run it at full throttle for any length of time!
Vary the throttle position and never keep a steady speed for more that a few seconds.
The typical break in is 1 gallon of gas. Then you can open up the throttle at leisure.
Keep in mind that after break in, if you run it at near full throttle all the time, it will wear out quickly.
I am sure others will post their techniques soon...

 

[GoFastBicycles]

I say ride it hard but not for long periods. you need to seat the rings. They aren't made of china just made in china.

Adam

 

[Mac]

I suggest watching hot hot it gets initially, I feel it should be ran and shut down several times during the first couple of short runs, it has always worked for me, should be able to touch the head after shutdown BRIEFLY. good luck!
Mac

 

[BRETT87]

Ride it hard but DO NOT HOLD IT FLAT OUT ALL THE TIME and do it for about 3 tanks

 

[noco]

just ride normal....full throttle....half....what ever you feel comfortable with....just ride and make sure your not too lean(check your plug)

 

[Venice Motor Bikes]

I cuncur with the 'just ride it normally' crowd... (You're not gonna hurt it.)
Always make sure it's good 'n hot before ever bringing it up to full throttle!!

I use 2 gallons of 24:1 gas/ oil to break 'em in. It will still keep running better & better even into it's 5th gallon of gas; so don't worry about trying to tune it for speed until then!!

 

[oldtimer54]

Thanks guys thats great advice.

 

[AZMotorbiker]

I've been running mine about 1/2 throttle with *occasional* bursts to 3/4 or full, but only for a brief period (usually long enough to get around any normal pedal bikes in my path, LOL) I also take a short break every 10-15 miles or so for about 5 minutes. I figure that's about as good a break-in routine as any.

-AZ

 

[N8dogg]

I just got mine a few weeks ago and started out riding it pretty hard right off. I did stay away from the long full throttle runs though. Im at 130miles right now and its running better everytime I ride.

 

[junked]

It's probably too late, but I recommend pulling the head and jug (cylinder) off and cleaning it all before you ever start the engine or even turn it over.

These engines can be rather dirty from the factory and you just never know what was left behind during assembly. My engine shows signs of foreign material being present from the factory.

It is simple to do and can make a big difference on longevity, reliability, and of mind. I learned my lesson.

 

[Junster]

If you look at a new cylinder you'll see the cross hone is very fine. Not coarse like old motors were. You have a very limited time to get the rings to seat properly. You do need to run it for 3-5 minutes then off till it cools all the way. (bout a half hour) Do that twice to let the bearings seat. I replaced my entire top end after about 2000 miles because the pin in the ring groove came out and gouged the cylinder. I broke in the new top end as fast and as hard as I could with keeping track of it not getting to hot. This top end has more compression and the motor has better power and more top end speed than the old top end ever had. I also broke it in with opti-2 at 75/1 from start up this time. Not with 16/1 regular 2-stroke oil. I pulled the head the other day cause I blew the head gasket (see general discussion for pics, actual blown head gasket) The new cylinder is smooth as silk and my motor runs better than it ever has. I have a shift kit, tuned pipe, CNS carb. I can do 42mph on a flat road with no wind paced by a new car. Not checked with a bike speedo. I know everyone has different ideas on this. This is what is working for me.

 

[Dontwannawalk]

I don't pretend to be any kind of expert on these motors but will put in my experience.

The discussion has been " Do you use Opti 2 from the start??" and "If you use it from the start will it eventually break in" and " What ratio would you use?"

With a ZB 80CC I used a 100/1 ratio from the get go just to see if it would work. Since the motors are pretty low cost I decided to be a Ginny Pig. It started fast,ran cool, had great low end power and shook like it was having a fit. Top end was 23 mph until about 400 miles and it then started to climb up to about 30 mph but still vibrated like ____ over 26 mph. I just didn't take it over 26 mph until it started to smooth out and then kept running it up to max for short bursts. At one point it vibrated so much that I actually couldn't keep my butt on the seat at 30 mph. At 500 miles it started smoothing out so I could stay on the seat and it would hit about 32 mph reasonably smooth. This evening I took it for a ten mile ride from my home through the hilly part of my town, out to a park around a lake and back home. The vibration is mostly gone (as much as I expect can be with these little engines) and It topped out at 38+ mph & I have 650 miles on it. That's too fast, in my book, to ride a Huffy Mountain Bike. It doesn't run as cool as it did when it had only 50 miles on it but still has never been really as hot as I've seen some other types of small engines run. I think this is still the first phase of the test on the Opti 2 break in but, I think I'm sold.

Norm Starr

 

[Dogtown Burner]

If you look at a new cylinder you'll see the cross hone is very fine. Not coarse like old motors were. You have a very limited time to get the rings to seat properly. You do need to run it for 3-5 minutes then off till it cools all the way. (bout a half hour) Do that twice to let the bearings seat. I replaced my entire top end after about 2000 miles because the pin in the ring groove came out and gouged the cylinder. I broke in the new top end as fast and as hard as I could with keeping track of it not getting to hot. This top end has more compression and the motor has better power and more top end speed than the old top end ever had. I also broke it in with opti-2 at 75/1 from start up this time. Not with 16/1 regular 2-stroke oil. I pulled the head the other day cause I blew the head gasket (see general discussion for pics, actual blown head gasket) The new cylinder is smooth as silk and my motor runs better than it ever has. I have a shift kit, tuned pipe, CNS carb. I can do 42mph on a flat road with no wind paced by a new car. Not checked with a bike speedo. I know everyone has different ideas on this. This is what is working for me.

may steal your quote... too good!

 

[Rocky_Motor]

What about letting your bike idle for a bit then letting it cool? And do it for quite a few rounds. Or is that a bad way to break it in?

 

[Dogtown Burner]

What about letting your bike idle for a bit then letting it cool? And do it for quite a few rounds. Or is that a bad way to break it in?

Hey rocky, the engine won't break in if you do that. The whole idea of acknowledging "break in " period Is the sealing of the rings. Or rather "seating" of the rings. The engine needs to have a load put on it to create enough pressure.. It's a
Long story and there are lots of threads. Do a little more digging on the forum. The best way all us old timers agree on is to ride it like you stole it, and just make sure to not run the mixture too lean, and don't run WOT for long periods of time. The engine keeps getting better with time.

 

[Rocky_Motor]

Oh ok, I thought it was just heat not so much the pressure.

Glad I know, can't wait to do it! The days are goin by sloooowly I tell you what

 

[Dogtown Burner]

There are a ton of break in threads. Forgive spelling the website is running slow with iPhone. There is a thread where a
Guy posted a
Link to 2 stroke break in procedures a while back. It's interesting. The pressure in the head forces the rings out against the cylinder wall smoothing it out and forming a seal with their unique shape and fit. Low pressure from "no-load" running, causes them to not cut into the walls and therefore leaves minuscule gaps and leads to blow-by. End result is a slightly lower compression and the chane of piston clatter And definitely s shorter lifespan for the rings. And then a new head if you want it to be perfect seal ever again. You'll
Read That a Few guys have just scrapped badly broken in jugs and started over. Anyway, quit waitin' and go ride that bad boy. They're fun. Not as powerful as you might be expecting, but fun nonetheless. Start with the stock "2nd groove" needle clip position, smooth out the inside of the intake manifold. Widen it as much as you can to kind-of match the engine intake port width. do same for exhaust, careful with the delicate gaskets! Grease the clutch gears in the right side of the engine, gap the plug to at least .025, remove the silver cap on the plug tip, and hmm.. What else...? Have fun!

 

[Dogtown Burner]

It's probably too late, but I recommend pulling the head and jug (cylinder) off and cleaning it all before you ever start the engine or even turn it over.

These engines can be rather dirty from the factory and you just never know what was left behind during assembly. My engine shows signs of foreign material being present from the factory.

It is simple to do and can make a big difference on longevity, reliability, and of mind. I learned my lesson.

Does this thrash the gaskets? Some have sealant, some don't, I've noticed on case Covers

 

[BarelyAWake]

To pull just the head and cylinder involves four gaskets, head, intake, exhaust & base - of these there's only one that will definitely need replacement & that's the base gasket as it rarely remains intact during disassembly, even with a new, never-run motor.

If/when you purchase any new gaskets or have intact ones removed from the engine - I strongly recommend using them to carefully make trace templates, this will allow you to make your own, far higher quality gaskets using materials commonly found at any decent auto parts store, for the same price or less