i have broken in my 400ex motors hard too. i definatly let them warm up by cruising and varying the rpm. once it gets up to temp, i let them eat. i run the all the way to the stock rev limiter. i also let the compression slow me down, not the brakes. i have contacted motoman before. he mentioned to only put a small drop of oil on your finger and run it throughout the sleeve. do not not use more oil than that. he proceeded to tell me that he actually has put pistons in a dry sleeve before. however, he recommend using a small drop of oil on one finger and running that drop throughout the whole sleeve.

 

i dont agree with the 'rev'er up to the rev limiter" it doesnt make sence to me. the point is to get ur tolerances and ur rings set right. you do have to put the engine under load. i know this has been said already but i only let my engines rev to about 1/2 at full throtal (spelling) and ive had good success with it. just though id let everyone know.

 

I could shoot holes in the posted website way of engine break-in proceedures, and therories, but I will not.

I will tell you some facts that have been overlooked though.

I am 41 years old, and have been in the powersports industry since the '70s
I have raced, and built engines for many other aplications since. I still race, but have chosen Legends Cars as my sport, although I am recreational vehicle technition.

Here are some of my thoughts.

When an engine is new, or new cylinder, sleeves, pistons etc.. have ben installed, the method of break-in is normally focused on the rings. I have to bring to your attention that there are other parts to consider when deciding on your particular break in proceedure. The term " warm-up " needs the door kicked a little wider open here. Engines have different cooling systems and cylinder designs. Cooling of coarse being " air " and " liquid ". The inital warm up on these 2 types of cooling are different, and I will explain why.
Cylinder sleeves are not all the same, or will not react the same in all engines. Cylinders are of a few different types, closed deck, semi closed deck, and open deck. Closed deck is like a air cooled cylinder, the sleeve is in a solid cylinder, all the way out to the air fins. An open deck will be a engine where you lift the head and the cylinders are not attatched to the outer block, no metal holding the cylinders to the engine deck ( coolant passages totally visible ). And a semi open deck is like it sounds ( when the head is lifted off the block coolant holes can be seen between the cylinders and engine deck.
I vary the initial start-up break in time and run time on these different types of engines accordingly. When an engine is new, the cylinders are bored and honed to fit the rings and pistons, O.K. ( here's the kicker )... cold. An engine must be properly warmed up ( I recommend a number of times, with a complete cool down time in between ) so the cylinders can stabilize, and wear to fit the new components by getting hot to the touch then totally cooled down, cold to the touch, a number of times.
What I am getting at here is, cylinder distortion in each type of engine design I have mentioned above will vary when new, warm, proper " warm-up " procedures, and break in can damatically influence the engine life and performance, through cylinder stability at operating temps.
Not only does this initial warm up time set the cylinder up for operation and break in proceedures thereafter, but it also lets other engine parts time to 'get used to each other' like rocker arms, camshafts, rod bearings, crank bearings, balance shaft bearings and oil pump rotors etc...

Once this initial WARM UP, has been completed, THEN RIDE IT LIKE YOU OWN IT
But stay off the rev limiter ( don't get me started on the rev limiter subject, LOL )

In a nutshell, I don't advise just warming a new unit up ( once ) and riding it hard to break it in. WARM IT UP PROPERLY FIRST

just my 2¢ worth

----- Gregg -----

 

I believe Motoman addresses those issues also, here: Rod and crankshaft bearings.

I know there are a TON of theories out there, but Motoman has the hands on experience with over 300 of these motors, and has proven 1st hand that this method works!
Theories are great and all if you haven't proven them to be invalid. With the amount of times he has done this, along with lack of problems from doing it, I'd say that is pretty much the proof in the pudding (at least for me).

 

It seems very credible and he explains it very well...I dont really get the "infomercial" theme he's got going on with his site, but he's not trying to sell anything, and it is quite entertaining. But then some people just have a way with words to make them sound credible, like this guy... Well Ive got a brand new Recon in the shed that may be worthy of this theory, Im one of those guys that has to "see it to believe it"....

 

Yep, his explanations are in depth and tell a lot of secrets many have known for years. He has a distinct way to get his point across. Every time he brings up the subject of " Warm-up " he seems to hesitate a little and in the last arcticle you have linked, he even says not to REV an engine during start-up. I couldn't agree with him more. Any engine must be at operating temp before reving. The only thing he has gone indepth on, has been ' slipper ' bearings on the rods and mains, and I would have to agree totally with many to most of his views.
His description of manufacturing precise roller bearings are definately spot on, until a shaft is inserted into the bearing, and the bearing race is installed into a case. Most ATVs have ball crankshaft bearings, and not slipper bearings though. So if you have a crankshaft that installed into these bearings, and it is spun really fast, cold, the shaft in the center will carry a harmonic , that is unloaded into the bearings. Causing them to chatter, and hurt the precisely machined ball or roller bearing assembly. THE UNIT MUST BE WARMED UP AND COOLED DOWN TO BREAK IT IN THE FIRST FEW TIMES IT IS STARTED. Before the engine can be broken in the way he has stated. But I will stand behind his meathod of breaking in a motor, after this process has been done.
You can take a new crankshaft and get it INDEXED and find it is out 1 or 2 degrees. This will cause harmonics within the spinning bearings ( ball or roller ). And can cause them to chatter within their races. If the unit is " warmed up " many times as I have described in my above post, the engine parts will have time to get used to each other and have a less chance of failure ( or poor performance ) because of cold operaton or high RPMs on initial startup.

I recommend a new air cooled engine be started, warmed-up, and cooled completely at leas 6 times, BEFORE a high load break-in ride for the pistons and rings. Liquid cooled engines vary on these times depending on deck design. It gives the cylinders time to expand and contract with the pistons to fit perfectly.

Closed deck cylinders will have the most stable cylinder walls at higher loads, where open deck cylinders will tend to be less stable. They will distort more in certain areas, until properly broken in. Keeping cylinder walls stable ( or true ) at high rpms, or torque, will lead to extended engine life and performance. Different piston materials, friction coatings on pistons, or friction materials impregnated into piston casts, along with cylinder wall coatings such as nikisil, to reduce friction are used to help maintain cylinder stability as well as increase performance and engine life.

If a engine is started and rev'd cold, the pistons which are of a softer metal, than the cylinder walls, will expand very rapidly, compared to the cylinder wall. This my friend will tighten the clearance between the piston and cylinder wall, and can cause scoring. Leading to more friction in that cylinder. Amplifing the drag on the crankshaft. Now what was I saying about harmonics within a shaft inserted through a roller bearing, Hmmm.

Thanks for the links fellas, I enjoyed reading them, and once again, agree with him on a lot of his research.


----- Gimp -----

 

Excellent posts!

 

i have a 2005 honda rubicon. it has about 7.8 hours on it so far. i have opened it up a few times to see what it would run. on the break part. i pulled a 12ft john boat that had about 10 inches of water in it out of the back water to dry land and about 20 yards across the dry land. the four wheeler has hell of alot of power. but my question is would that have hurt the engine in power and performance? i can tell that it seems like maybe a small power loss or throttle response from the four. should i not worry about, will it regain its power after my first oil change, contact the my honda dealer. need some response

 

Thomas, I wouldn't worry about it, especially if the unit was at proper operating temperture before you but a load on it. Power, throttle response and smoothness should increase after the first oil change and then just get better until everything wears in. In normal automobiles, this sometimes takes 10,000 miles.

I have to go with Gimpster on much of what he says, particularly bringing to light that there are more parts to an engine than merely the rings and the cylinder. Race engines have a goal: top performance. Longevity and durability are not as important as to someone who does not have the luxury, time, money or inclinaiton to replace and/or tear down and rebuilt the engine every so often or when performance wanes the slightest.

I am familiar with piston aircraft engines, typically 2000 TBO (Time Before Overhaul) or thereabouts. The measure of maintaince, power management and luck(!) is whetehr or not your engine makes it to TBO - or beyond. Based upon this type of operating environment and the TBO ot TBO-plus goal, I can say this.

Patient warm-up before take-off rolls (full power, typically full load) is a big, big factor. Frequent oil changes help. Proper air fuel mixture; keep in mind that there is 25% less O2 at 10,000 feet than there is at sea level. Piston engine airplanes have a mixture control that is adjustible in flight so that you can lean the fuel flow as you gain altitude and richen the fiel flow as you descend. Running too rich is not good and running too lean is worse.

When a new engine comes back from overhaul it's broken-in with mineral oil. Pattern work (take-offs and landings) are frowned upon during breaki-in while level cruise at high power settings is preferred.

I have flown an aircraft with a Lycoming engine that went well beyond TBO with good compression up to the day it was flown to the shop for an overhaul. I attribute this to the maintainance and operating style/habits utilized. Keep in mind that cooling is typically not a problem for light aircraft and also keep in mind that these engines have a comparably low horsepower rating for their cubic inches compared to engines used in other applications and certainly compared to the typical ATV or motorcycle application.

When you get a new ATV, you are not just breaking in the engine, but also every other mechanical part on the unit. New Process Gear tell yous not to tow for the first 1000 miles on a new differential/planetary axle.

I don;t know who is right or if anyone is wrong, but I do not race. I am looking for long service life and trouble free operation with about as good performance as can be expected but I an NOT looking to eek out the last ounce of performance at the expense of longevity. This is just me and my applicaitons.

According, I

Warm-up carefully before operation.
Change oil and filter frequently.
Wait until at least 50 or more hours before switching to synthetic oil.
Vary throttle during break-in.
Stay off the rev limiter (or even close) but do load the engine on and off.
Allow the engine to rev down on its own as much as possible.
Use heating and cooling cycles and hours and measurements of break-in.
Try to speak kindly to the machine and not yell at it too much for the first 10 hours.

 

LMAO, good post !!!!

That made my day, lol

----- Gimp -----