Break in procedure

[2fun]

Originally posted by woody_raptor
I have bought quite a few brand new four strokes and I have babied some, and ridden the heck out of others and I honestly have never been able to tell a difference.

Don't the 4-strokes go through somewhat of a break in before you buy them??

[Woody_393]

As far as I know they don't ... well unless you get a pumpkin.

[2fun]

Too bad all motors aren't broken in when you get them.

That way, you wouldn't have to hold back for the entire day (almost) when you finally get a chance to ride it!

[Woody_393]

I hear you... It is almost more than one can stand to not get on it.

[tc66nova]

Ther are a lot of different ideas on this thread and I will throw in my two cents based on 25+ years of machining and drag racing experience. NEVER EVER use synthetic oil to break in an engine of any kind it WIL prevent proper ring seal. Synthetic oil is fine after the engine is broken in. As far as RPM during break in ,don't use excessive RPM but do put the motor in a higher than normal gear and accelerate briskly. Do this three or four times and the load put on the rings will go a long ways towards breaking in new rings. Idling an engine especially when new is the worst thing that you can do, it accelerates cam wear, glazes cylinder walls, increases oil contamination and all sorts of undesirable conditions inside your motor. The varying engine speed helps break in by letting tight spots get hot and expand and then to cool back down when speed slows down, do this often for your first tank of gas. Piston clearance is based on bore dia. and piston design. If you check specs for most water cooled engines 2 or 4 stroke you will see that they are very similar or even identical as far as piston to cylinder wall clearance. The piston does not have much to do with compression other than ratio, the rings "hold" compression (when properly broken in) the piston just carries the rings. As a matter of fact look closely at a piston and you will see that the area where the ring package is located is undercut and never contacts the cylinder at all. As far as sanding a piston I would never disturb the finish that the manufacturer has spent thousands of $ on R&D to determine the best finish for piston life and performance. Lastly as far as break in I have found the best performance and the best life out of running the engine through one heat cycle changing the oil & filter then warming it up untill the OIL is warm and then ride it like you stole it. Infact in my drag race engines I heat the oil with an electric oil heater before I ever fire it, feeling the engine for heat does not tell you if the oil is warm.

[2fun]

Good info tc66nova!

Also, wanted to say welcome to ATM (all things moto)!

Hope you decide to stick around, and post often!

[Woody_393]

Welcome to ATM tc66nova

Where abouts in NE Ohio are you located? I was in Mt. Vernon about 8 Months ago, working for Rolls-Royce. Nice Area.

Anyway, thanks for the info. I think you are dead on there.

Oh, and can I say that your Birthday is the best day in the entire year.

From the look of your mods looks like you are buddy or relative of James?

[tc66nova]

03 CRF450

Thanks, but no I don't know nor have I ever met James but I have been Building motors for a long time and I can usually see the reason behind new ideas and recognize what works and what doesn't. I think ATM is a great site and check it almost daily. Sept 15 is a pretty good day, have you ever noticed how many great minds were born in Sept? Just look at you and I LOL.
As far as where in northeast Ohio I am about half way between Cleveland and Akron in a really small rural town named Hiram. Except for the cold winters I think Ohio is the greatest place in the world. Thanks for the welcome, I hope that I can help a few on this board and learn some things myself.

Terry

[Woody_393]

Right on. Ya, after reading the power now thread, I see that you aren't. So my bad.

I'd have to agree about Sept. Very good month for smart people to be born. Now if I could just ride

[2fun]

Originally posted by Woody_CRF
Right on. Ya, after reading the power now thread, I see that you aren't. So my bad.

I'd have to agree about Sept. Very good month for smart people to be born. Now if I could just ride

I have to agree with you on this one!!!

[Woody_393]

I didn't even notice that you were one of us... That is sweet...

I knew I liked you, I just wasn't sure why? Now I know.

[2fun]

Originally posted by Woody_CRF
I didn't even notice that you were one of us... That is sweet...

I knew I liked you, I just wasn't sure why? Now I know.

You mean it wasn't because of my charming good looks??

[Woody_393]

LOL, Uhhh, Nope.

[Dirt_Boy77]

I agree that you risk a cold sieze if you don't let the bike warm up before letting it rip, On my bike I start it and start letting it get warmed up while I put my helmet on, I then sit on the bike and wait until I can't keep my hand on the head or cylinder then I put it in gear and take off, This has given the Piston,Sleeve time to warm up and expand properly. I guess one way on a water-cooled bike to tell if its warmed up good is to put your hand on the radiator,when it gets good and warm then you know the engine is ready to go. Matt

[2fun]

Ok, here is my procedure for breaking in an engine.
Hopefully I didn't leave anything out.

This is for a 2-stroke only!! I go with the Motoman method for my 4-strokes!!

Generally one tank of gas is plenty for break-in.
Use non-synthetic oil for your first tank of gas. Synthetics are too slippery, and will not allow the rings to break in properly.

There are many different methods as mentioned earlier.
I like to put my motors through several heat cycles prior to taking it out and riding it.
My last two motors I put through 10 heat cycles each, though it is not necessary to put them through that many. My theory is the more heat cycles the better.

I let the motor get warm to the touch and then shut it off. Let it get stone cold before the next heat cycle.
I lightly blip the throttle not holding it at any constant rpm the entire time (vary the throttle). Don't over-rev it, just lightly blip the throttle for the first few heat cycles.

Then I take it out (after 5-10 heat cycles in the shop) and ride it varying the throttle up to half throttle for the first ride. During this 1st ride, I'll vary the throttle (up to but not beyond) 1/2 throttle. Do this for ~ 15 mins.

Let it cool all the way till its cold.

2nd trip out, vary the throttle not going above 3/4 throttle. Ride it for 15 mins, and then let it cool to stone cold again.

3rd trip out, vary the throttle and take it to full throttle, but do not leave it there for an extended period of time. A few seconds at most. Do this for 15 mins and let it cool.

Do a jetting run now to be sure you are jetted correctly. Do this with a FRESH WHITE plug!!
Re-Jet if plug color indicates the need.

Now rip on it giving it gobs of throttle, still varying the throttle. Work the motor hard this time, and generate plenty of heat. Do this for at least another 15 mins.

Your motor should now be broken in.

Run the rest of the gas out of the tank and switch to a fully synthetic if that is what you normally run.
Re-Jet the bike for the new mixture, and you should be good to go!

Please note that whenever taking the bike/quad out on a run, it is ABSOLUTELY NECESSARY TO LET THE MOTOR GET WARM TO THE TOUCH BEFORE RIDING! OTHERWISE YOU RUN THE RISK OF SEIZURE AND YOU MAY HAVE TO RE-DO THE ENTIRE PROCESS WITH A NEW PISTON, RINGS, AND BORE JOB!!!!!

[Madman393]

Cast your vote and rate this thread to send it to the KB for all time!

[Woody_393]

Good stuff. 5 star here.

[2fun]

Yep, I believe I gave it 5 stars too.

Either this one, or some of the others.:

I've rated more than one in the last few hours.:

[ROOSTER_KTM]

Looks like I did it the long way. First, I had to run 2 tanks of gas at 50% throttle. Then I had to run 1 and a half tanks of gas at 75% throttle. Then I got to go full throttle! I had gone 180 miles of breaking in before i could blast it!
Justin # 701

2003 KTM 250 EXC RACING FOUR STROKE

[RedFan]

HIG4s
"BUT NOTE, the web site says this is for any 4-STROKE engine, and I can attest that this is not the best way to break in a 2-stroke. Heat cycle 3 times, take it easy for a tank of gas. If you run a 2-stroke hard and fast right away they can seize"
Agreed but ->
This procedure is to be done only on a fully warmed up bike which can be done by the methods mentioned by others here "blip, blip" or slowly riding around on flat ground. The Heat Cycle method is designed to "heat treat" the metals. With common materials there isn't any heat treating going on. Also this procedure is so short the bike will never get very hot. You simply need to seat the rings. I agree it doesn't follow common wisdom but often truth is stanger than fiction. My friend broke in his new GSXR and cruiser this way and the oil comes out looking new.