Running a new ATV engine can be a nail-biting experience. It’s important to get it correct. The break-in period will affect how the engine performs throughout its life.
To break in a new ATV, follow your manufacturer’s break-in recommendations. A typical new or rebuilt engine break-in procedure is as follows:
1 Use regular engine oil for the break-in procedure
2 Check fluid levels
3 Warm engine
4 Check for leaks
5 Run engine up to 75% throttle in 2 and 3 gear for 30 minutes
6 Change oil and filter
7 Repeat 5 & 6, and the engine is run-in
In this post, you’ll learn how I break in a new engine, and I’ll explain why I do it this way.
Getting a new set of wheels is an exciting time. These toys are expensive. You want to treat them right and have them for many trouble-free years.
When breaking in a new ATV, it’s the engine we’re concerned with. Most other components don’t need a break-in period.
I’ve been lucky enough to own a couple of new ATVs and a ton of used ones. I’ve rebuilt lots of engines, and in this guide, you’ll see how I break them in.
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When engines are built, the cylinder is honed or crosshatched. That’s a system of polishing, if you like, the cylinder wall surface.
Crosshatching the bore creates an abrasive surface, and you’d think that counterproductive, but crosshatching is needed to help shape the new piston rings to the exact shape of the cylinder wall.
The better the cylinder and ring surfaces pair, the better she’ll perform over her lifetime. Your engine will be noticeable more:
The break-in starts with the oil.
Synthetic and semi-synthetic oil is excellent, but that’s a problem when breaking in a new motor. We want the rings and crosshatched bore to make good contact. Without contact, the bedding won’t happen.
Synthetic oil is too slippy for break-in. If your engine has synthetic oil in from the factory, change it, run with regular petroleum-based oil, just for the break-in procedure.
Check the fluids, allow the engine to idle for a few minutes to warm up. Take this time to check for any leaks or loose components. When the engines warm, we’ll start the break-in procedure immediately.
You’ll need somewhere you won’t be impeded. It isn’t practical to run a break-in session where there’s traffic or pedestrians etc. A quiet country road is ideal.
Run the bike at 75% throttle in 2 and 3 gear, varying the time spent at 75%. Allow the engine decelerate, again varying the time spent decelerating. Run this cycle for 30 minutes, keeping an eye on the temperature.
If the bike gets too hot, use good sense, run it in a higher gear and back off the throttle.
The break-in period doesn’t last long on a new engine. For most, the window is a few hours of running. After that, the opportunity is lost. The rings and cylinder are pretty much as mated as they’ll ever be.
Do you think 75% throttle is too much? Yea, I can see why you’d think that. I run at 75% because I want the piston rings pushed hard against the cylinder wall for as long as possible during the break-in window.
The higher rpm creates more ring cylinder wall pressure and, therefore, better pairing.
After 30 minutes run time, drop the oil and filter and replace again with non-synthetic petroleum-based oil. I’ll change the oil because at this stage risk of contaminants in the oil is high. The break-in sessions will cause fine metal particles to circulate the oil system.
Check all fluids and allow engine idle to operating temperature once again.
Repeat the break-in drive cycle for another 30 minutes, as before.
After two-thirty-minute sessions, your engine is broken in. I changed the oil and filter again, but this time use the recommended grade oil. You may be semi or fully synthetic. I changed the oil again after about 8 hours of running time and from then as per your manual.
If your new ATV is CVT belt-driven, break-in is minimal. Most manufacturers will ask that you refrain from running at full throttle until the belt beds in. Overheating the belt can cause glazing and transmission slip.
That’s it, congratulations, and enjoy many years of trouble-free ownership.
You may find the following posts useful:
How often to service bike?
How often should I start an ATV?
Storing ATV outside
ATV Riders Forum > ATV Riders Mechanical Section > ATV Powertrain > Breaking in a Fresh Top End
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Exrider434
11-03-2007, 01:00 PM
Like the title says, In your opinion what is the best way to break in a fresh top end?
NPelletier
11-03-2007, 01:31 PM
2 or 4stroke?
KXRida
11-03-2007, 02:10 PM
do two heat cycles, then ride for 15 minutes trying to keep a constant load on it.
Exrider434
11-03-2007, 08:09 PM
4 stroke, and what do you mean by heat cycles?
KXRida
11-03-2007, 10:51 PM
start it up and vary the throttle through rpm ranges 3-5 minutes and until the top of the radiator is hot to the touch, then shut the bike off and let it cool for atleast an hour. Longer is better. Repeat this again, then ride it with a constant load on it. You can drag the rear brake a little if you need to.
Exrider434
11-04-2007, 12:20 PM
what do you mean ride with a constant load on it? sorry for all the questions first rebuild
Keats
11-04-2007, 02:46 PM
giver hell. don't hold it at WOT, change the oil often right away and your set.
KXRida
11-04-2007, 08:56 PM
Originally posted by Exrider434
what do you mean ride with a constant load on it? sorry for all the questions first rebuild
Keeping the engine pulling and having "tension" on it for lack of words.
Like when you're going up a hill, etc. This is just the method that I have used on all my bikes. FYI moto814 racing uses this on all his engines so that is where I got it from. Reguardless just change the oil as stated above. Not really nessicary because there isn't really a whole lot of new metal to metal contact, but fresh oil can never hurt.
chad502ex
11-05-2007, 09:13 AM
constant loads on a new engine is the worst thing you can possibly do to a new engine...
an engine requires pressure to properly build pressure to seat rings into the fresh cross-hatching... the cross-hatching is the file to the rings..
KXRida
11-05-2007, 01:38 PM
Originally posted by chad502ex
constant loads on a new engine is the worst thing you can possibly do to a new engine...
an engine requires pressure to properly build pressure to seat rings into the fresh cross-hatching... the cross-hatching is the file to the rings.
.
it's not a new engine
Pojo450r
11-05-2007, 02:34 PM
its a new top end . i just built new moter dasa 510 kit with 13.5 to 1 je piston new crank this is how i broke mine in 1st start it let it warm up mabey 5 to 8 min at a good constant rpm not idle. i changed oil checked valve clearence then rode about 10 to 15 min at steady rpm DO NOT LUG MOTOR in 1 or 2nd gear at kep it smooth rpm. then i changed oil did final valve check and went out rode easy with my friends mabey 4 hrs i changed oil and now i just ride it like i always ride and havent had any problems. oil is the cheapest insurance u have change it often! also web cam 493 grind and +1 ex valves im happy with it
tank69
11-06-2007, 10:11 AM
Originally posted by chad502ex
constant loads on a new engine is the worst thing you can possibly do to a new engine...
an engine requires pressure to properly build pressure to seat rings into the fresh cross-hatching.
.. the cross-hatching is the file to the rings..
Can you prove this? How did you come up with this reasoning?
KXRida
11-06-2007, 02:27 PM
Originally posted by Pojo450r
its a new top end .
and? Not a new motor. You're only seating the rings and at most wearing a new groove into the wrist pin.
roadthrills
11-13-2007, 03:17 PM
A fresh engine does require some pressure to help seat the rings. Regardless of what you do the combustion event will do that. It is more so the friction from the crosshatch that seats in the new rings. That's why you never put Slick 50 or any other additive in, until after break-in. The warm-up cycles are a great idea. I do 3 of them on all my 2 and 4 strokes. Then vary the throttle constantly with no more than 2/3 for the first tank of gas. Change the oil and RIDE IT LIKE YOU STOLE IT!!
A A R O N
11-15-2007, 09:09 PM
When I built my YFZ motor I followed the exact instructions of a very reputable engine builder and it worked out very well for me.
The motor was very reliable and never burnt a bit of oil.
I used Schaeffer's 15w40 semi-synthetic for break in and normal use. There are many different oils that i'm sure will do the job just fine.
Start it up, keep the rev's in the mid to high range right away for a few seconds, hit the rev limiter once or twice for a SPLIT second, keep the revs up for a bit longer, shut it off, and it's ready to ride, race, or however you're gonna ride it. "break in time" was only about a minute long [and at 1 a.m. haha, the neighbors were happy im sure :devil: ] and that's all it takes . With these motors it's necessary to get the rpms way up there right away to get oil to the top of the motor and keep from causing problems with lack of oil to the cams, etc...
:devil:
zrpilot
11-15-2007, 09:54 PM
Originally posted by A A R O N
When I built my YFZ motor I followed the exact instructions of a very reputable engine builder and it worked out very well for me.
The motor was very reliable and never burnt a bit of oil.
I used Schaeffer's 15w40 semi-synthetic for break in and normal use. There are many different oils that i'm sure will do the job just fine.
Start it up, keep the rev's in the mid to high range right away for a few seconds, hit the rev limiter once or twice for a SPLIT second, keep the revs up for a bit longer, shut it off, and it's ready to ride, race, or however you're gonna ride it. "break in time" was only about a minute long [and at 1 a.m. haha, the neighbors were happy im sure :devil: ] and that's all it takes . With these motors it's necessary to get the rpms way up there right away to get oil to the top of the motor and keep from causing problems with lack of oil to the cams, etc...
:devil:
Hey Aaron,
Long time no talk... How ya been?
Oh by the way, Aaron has some connections and the engine builder he refers to really knows his stuff, GOOD ADVICE!!!!
Mike
Toadz400
11-15-2007, 10:01 PM
Originally posted by A A R O N
When I built my YFZ motor I followed the exact instructions of a very reputable engine builder and it worked out very well for me. The motor was very reliable and never burnt a bit of oil.
I used Schaeffer's 15w40 semi-synthetic for break in and normal use. There are many different oils that i'm sure will do the job just fine.
Start it up, keep the rev's in the mid to high range right away for a few seconds, hit the rev limiter once or twice for a SPLIT second, keep the revs up for a bit longer, shut it off, and it's ready to ride, race, or however you're gonna ride it. "break in time" was only about a minute long [and at 1 a.m. haha, the neighbors were happy im sure :devil: ] and that's all it takes . With these motors it's necessary to get the rpms way up there right away to get oil to the top of the motor and keep from causing problems with lack of oil to the cams, etc...
:devil:
I agree with this. No reason to go easy on the engine at all during "break-in". Only going to cause more problems down the road. I did basically the same thing to this with my YFZ and sometimes I wish it burnt oil when I put a little extra oil in. I've got 2 1/2 years on the engine and I've been everything but easy on it. Of course I maintain it but I try not to ride it like a sally and it still runs like a top, *knock on wood*.
A A R O N
11-15-2007, 10:37 PM
Originally posted by zrpilot
Hey Aaron,
Long time no talk... How ya been?
Oh by the way, Aaron has some connections and the engine builder he refers to really knows his stuff, GOOD ADVICE!!!!
Mike
Oh, I've been pretty good. I've just been too busy to get on here much lately between school and work. I'm about to start doin' a frame up build on my quad to get ready for nationals next year now too. It's kinda sad being that it's an '08 and I've only got about 10 races on it and it's about to be in a thousand pieces on the garage floor :blah: So what have you been up to with your quad?
....and toadz400---2 1/2 years without a rebuild:eek2: haha, I guess that's not too bad, but I sure couldn't do that.
...I get bored with power to easily :p My current motor has been stock for 5 months and that's WAYYYY too long:macho
zrpilot
11-15-2007, 10:50 PM
Originally posted by A A R O N
So what have you been up to with your quad?
Not much, running good, well at least as good as a 400EX can. Our mutual friend gave me some great advice to eliminate a low end bog. It has never ran better!!!
He also extended an invite to go ride in FL this winter! I'm working on doing that!!!
Take care Aaron!
A A R O N
11-15-2007, 10:57 PM
Originally posted by zrpilot
Not much, running good, well at least as good as a 400EX can. Our mutual friend gave me some great advice to eliminate a low end bog. It has never ran better!!!
He also extended an invite to go ride in FL this winter! I'm working on doing that!!!
Take care Aaron!
That's good to hear, that it's running well! That's a long haul, but that would be tons of fun to ride down there.
Good luck with the quad mike!
KXRida
11-16-2007, 06:45 AM
I'd still be rather skeptical of putting a fresh engine straight to the rev limiter.
Aceman
11-16-2007, 08:41 AM
Originally posted by KXRida
I'd still be rather skeptical of putting a fresh engine straight to the rev limiter.
These guys are trying to cold sieze a piston! I just hope people reading these type of posts don't believe everything that's typed.
People need to do their own research on engine break-in.
Toadz400
11-16-2007, 11:54 AM
Originally posted by Aceman
These guys are trying to cold sieze a piston! I just hope people reading these type of posts don't believe everything that's typed.
People need to do their own research on engine break-in.
Do you know what manufacturers do to the engines in the factory? They red line them. So your precious little engines have already been put to the rev limiter once before.
In order to break an engine in properly it needs to go through the entire RPM range. He didn't say hold it WOT for about 10 minutes and you're done. I can see why you'd be hesitant to go through the RPM range on a brand new engine but it needs to be done. If you break your engine in at low RPM's that's the range in which the rings will seal the best. To each their own though and people can break their engine in anyway they want to. This is just one way we do it.
KXRida
11-16-2007, 01:52 PM
I'll still stick to my heat cycles. Got over 200 hours on a single ktm 250sx top end.
Toadz400
11-16-2007, 07:50 PM
Originally posted by KXRida
I'll still stick to my heat cycles. Got over 200 hours on a single ktm 250sx top end.
That's fine, like I said, to each his own. I've got 2 1/2 years on my YFZ and it runs like a champ still. Couldn't be happier with it.
GPracer2500
11-16-2007, 09:05 PM
Engine break-in is always a hotly debated subject.
I think part of the reason the "correct" method seems so ambiguous relates to not all engines (or rebuilds) being the same. A couple of significant differences could include all aluminum cylinders with coated bores vs. sleeved iron bores, cast pistons vs. forged pistons, and maybe even air cooled vs. liquid cooled (with their differences in internal clearances). There's a lot of apples and oranges there.
What works fine for a stock cast piston may not be such a good idea with an aftermarket forged piston. What never causes an issue with a coated bore may be iffy on an iron bore.
Just something to think about.
alex450racer
11-19-2007, 07:49 PM
Originally posted by GPracer2500
Engine break-in is always a hotly debated subject. I think part of the reason the "correct" method seems so ambiguous relates to not all engines (or rebuilds) being the same. A couple of significant differences could include all aluminum cylinders with coated bores vs. sleeved iron bores, cast pistons vs. forged pistons, and maybe even air cooled vs. liquid cooled (with their differences in internal clearances). There's a lot of apples and oranges there.
What works fine for a stock cast piston may not be such a good idea with an aftermarket forged piston. What never causes an issue with a coated bore may be iffy on an iron bore.
Just something to think about.
Very well put
d3ktrix
11-21-2007, 03:29 AM
My break in method for a new top end:
-Put it together
-Run it till it warms up, change the oil
-Take it for a 1 hour easy cruise to make sure everything is good, change the oil.
-Ride it like I always do.
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But the fact is that sometimes a problem needs to be prevented even before the first sign of manifestation, so as not to get into a major repair. Today we will talk about the frequency of replacing piston rings.
Pit bike engine piston rings should be changed every 100 hours. But why is it so, at first glance, often?
Yes, not often at all, let's turn on our heads and just think, adding up the three main components - quality, operating conditions, general loads on the nodes (they are not small, by the way). The motors of the pits are overpowered to the point of impossibility, it is enough to remember that everything went from the miserable 50 cc fifty-fifty Honda Super Cube ... Draw your own conclusions, what margin of safety remains when the volume has increased from 50 cubic meters to 170 ...
But back to the rings.
When the engine is new, the piston and rings run tight and perfectly symmetrical to the cylinder running surface. Actually, wear occurs evenly and the piston runs smoothly, without unnecessary sliding of the skirt along the cylinder wall.
But as the piston rings wear, the piston has free play relative to the cylinder ... and this is what happens:
Due to the increased free play of the piston at critical points of rotation of the crankshaft, the piston moves from a completely symmetrical position to an angle. What does it threaten? Well, first of all, since the piston moves skewed, it actually does not just move up and down, but describes an ellipse. Accordingly, your cylinder will become an ellipse if you are too lazy to change the rings on time. With every hour of driving, the ellipse will get bigger and bigger, the piston will gobble up in vain (shown by blue arrows), and it will not work out its service life.
Speaking of piston. With proper maintenance, timely replacement of rings, valve stem seals; when lapping and adjusting the valves, and, of course, competent running-in, the motor can run up to 400 hours. During this time, he must survive 4 replacement rings, and then a piston for boring, and indeed the engine for bulkhead as a whole.
But back to the rings.
When the ellipse becomes unacceptably large, the piston already reaches critical angles and begins to rub its surface against the cylinder walls (shown by pink arrows). Naturally, gradually a kind of surfacing forms on the walls from the rubbing piston, and at one fine moment the piston wedges, tears off the skirt, hits the valves in pieces, they, in turn, bend into knots, and, finally, the connecting rod bends.
And all you had to do was buy two gaskets, one for the head and one for the cylinder, rings, just change and enjoy life. Along the way, of course, I would change the valve stem seals every 100 hours and grind the valve: anyway, the motor is disassembled. Better to do everything right once and ride without repair for the next 100 hours.
Bottom line: Do you want to use the entire resource of the piston and leave the prescribed 400 hours? Then change the piston rings every 100 hours. Do not be lazy, the whole procedure will take at least 6 hours, and the price of spare parts .
.. not the price in general.
"The rings and caps were changed in the engine. Now I'm wondering how long the engine should run in and what to do with the oil after that?" The fact is that all factory recommendations for running in refer to cases of repairs in which not only piston rings, but also pistons, connecting rods and main bearings were changed, liners were changed or cylinders were bored and honed. All the practitioners we interviewed agree on the need to break in an engine after replacing piston rings alone, but each of them has their own opinion on how and for how long the engine should be broken in. If we sum up everything we heard, and also analyze what is said about the post-repair running-in of parts of the crank mechanism by European manufacturers, we get the following.
During the break-in period, the vehicle must not be loaded with more than two thirds of its full load capacity, trailer or other vehicle must not be towed.
It is required to avoid engine operation in modes with revolutions exceeding, again, two-thirds of the maximum. The speed of movement is not higher than the same two-thirds of the maximum. Undesirable are long climbs uphill and driving through streets full of traffic jams, highways with high traffic, where you may have to frequently overtake other vehicles or brake hard. After the first thousand kilometers of break-in, it is necessary to change the oil and filter. In the next one and a half to two thousand kilometers, the load on the car and its speed can be increased, but not more than by 10-20%. Oil and filter after 2.5-3 thousand km should be changed again. At this point, the run-in is considered complete, but before a run of 5 thousand km after repair, it is not recommended to get involved in active driving.
Most of the discrepancies among practitioners are observed in the approach to choosing the brand of oil for the break-in period, the need for a second oil change after 2.
5-3 thousand km for the case when only piston rings were changed in the engine, as well as on the issue of running in idle mode, when, after repair, the car is rolled out of the workshop, the engine is started and allowed to idle for some time. The differences in the recommendations for choosing oil are such that, in our opinion, it is better not to listen to them at all, and not spare money and fill in what is recommended by the instructions for normal operation. Many experts believe that it is not necessary to change the oil after 2.5-3 thousand km if some piston rings have changed, while other parts of the crankshaft remain the same.
Regarding the break-in in idle mode, the opinion of the German company Kolben Schmidt is curious. Although some experts believe that it is with such a gentle break-in that one should begin to return the engine to service after repair, according to KS, it is harmful to the motor and can lead to severe wear and even damage.
