How To: Break in an engine

[BlasterEaten250]

Many people buy new atv's or rebuild there engines. When you have a new engine with no hours on it, you must break it in. Breaking in an engine properly will affect how long your engine will last. If you do it properly, your engine will last longer. I will tell you the procedures of breaking in a 4 stroke engine.

1.When you get the bike, or are done rebuilding, make sure you have the right amount of oil (brand new) in the bike. Make sure your filter is clean also. Install a new spark plug.

2. After that, for the first 10 hours of opperation, do not go past half throttle. Try to go different speeds as much as you can, but do not go past half throttle while riding. If you do, this could harm the engine. When you are riding, try not to put much stress on the engine (ie. climbing hills etc..)

3. After 10 hours of opperation, go 5 more hours, except this time, you can go 3/4 throttle. Do not go over 3/4 throttle. Again, try to vary your speed as much as you can.

4. After you have completed the riding part (15 hours total) adjust the valves.

5. After adjusting the valves, change the oil again to get rid of all the metal particles that are a result of the engine getting seated all together.


To learn how to adjust the valves, refer to this Remember, when adjusting valves and changing oil, always work in a clean environment, you dont want any dirt or dust getting in your brandnew engine.
I hope this has helped you some

[underpowered]

Anotehr method of break in can be found here, at http://www.mototuneusa.com/break_in_secrets.htm

[BlasterEaten250]

It is good to take things safe though. 10 hours could save 3 years.

[flyin#5]

sorry man... but im going to have to disagree with your break in procedure.

there is simple science to it, engines work on very close tolerances and the slightest thing wrong in your engine can mean disaster, or in this case more compression(power) or less compression. yeah, you have the rednecks that will tell you ride it like you stole it during the break in period... but im telling you, thats not the way to go. i have done a few to many rebuilds on the blaster, and have seen SIGNIFICANT im talking a 7psi difference on a two stroke using this method. the break in process is even more crucial for 4 strokes.

Heat Cycles

step 1-when you rebuild or get a new quad the first thing you want to do it start it up and let it idle until the cylinder becomes to hot to touch for a couple seconds. then shut it off and let it cool COMPLETLY.

step 2-once it cools off COMPLETLY again turn it on and let it idle until the cylinder is to warm to touch for a couple seconds. now its time to start riding. the first thing: NEVER stay in the same RPM range for more than a couple seconds. always vary the throttle. never put the engine under any load (dont go up steep inclines, ride with other people, or be in to high of a gear so the engine bogs down). you need to ride it for 5 minutes the first cycle not going over 1/4 throttle. after you ride for 5 minutes park it and let it cool completly.

After it cools completly repeat step 1 and keep repeating it until you have about 20 minutes of ride time on it.

*NOTE* its a good idea to keep track of total engine run time (warmup and ride time) and just ride time.

step 3 do exactly as you have been with step 1, but now go to 10 minute increments, not going over 1/4 throttle until you have 40 minutes ride time on it. then go about to 1/3 throttle.. ALWAYS VARYING.

step 4now go 10 minutes at a time not going over 1/2 throttle until you get an hour and 20-30 minutes on it.

step 5 now you can go to 15 minute's a ride if you want... id stay more towards 10 though.. so maybe find a medium at 12-13. keep doing everything the same, except you can go up to 3/4 throttle until you get 3-4 hours on it, or until your compression stops rising.. ill explain more:

the best way to know if your engine is fully broken in is testing compression. you will see the compression rise after every couple rides (or should), when the compression stops rising that means the engine is fully broken in. most people are to lazy to check the compression that much, but its highly reccomended. if you are one of those people who are lazy 3-4.. possibly even 5 hours is the normal break in time. after you reach 3 you should be fine going out near WOT, but i would keep varying the throttle until you get 4-5 hours on it.

im sure your wondering why this method works.. so i'll explain for those who want to know.

when a cylinder is honed, and when rings are made they have what you call "high spots". just like if you cut a piece of tubing you always get a little metal sticking up that you need to grind down. well... breaking in your engine is grinding that excess metal off your tubing. if you put tubing you just cut on the grinder and jam in on there... press as hard as you can you will get that excess metal off, but you'll take some length off that tubing as well.. and when you go to weld up your project, it wont be as precise.

its the same deal with cylinders and rings, if you go out there and ride it like you would any other day.. or race it, you heat the engine up to fast and not only does it wear away high spots, but it takes away the low spots... which takes away compression. not only do you have less compression, but you have less ride time before your cylinder gets glazed over (the cross hatchings dissapear). its an easy way to get more power out of your machine.. it just takes patience.

[BlasterEaten250]

There is many different ways to break an engine in. They way I said was from a clymer manual. That is how I learned it. I think my brother broke his in the way you said. And it works fine too. A big point of this thread is to make sure people do break it in. And it will tell them a way how to do it. Both ways work.

[flyin#5]

i agree.. it is important to break in your engine and more people need to realize this.

i know you got this info out of a clymer manual, but that doesnt mean its right. if your engine is fully broken in at 3-5 hours, and you keep going easy on it during that time and 10 hours or more past that your rings will not seat correctly, and its a waste of valuable riding time! also your method doesnt say anything about heat cycles, and if you ride for 2 hours at a time not going over 1/2 throttle its going to get much hotter than you want it to right away. its not precise enough... you need a time when you only go up to 1/4 throttle, then half, 3/4, and finally wot.

[raptor brothers]

I have always taken it easy for the first tank(not going over 3/4 throttle).Riding 10 to 15 min. at a time then letting it cool & doing it again(never had a problem).I also change the oil after the first tank.I always wandered why the owners manual(for my 660 & my 700) goes into so much detail about break in ,but does tell you to change the oil untill the 20 hr. service?The oil is so dirty after the first tank.I feel parts are made so much better now(tighter tolerances),that break in is shorter.I was also wandering if the rings weren't seated right wouldn't it smoke like crazy since they are what scrapes the oil off the cylinder walls & seals the oil out of the combustion chamber?

[beerock]

i did a how to on this in the 250r forum

[EXevan91]

there are many many diffrent "beleifs" on the breakin stage. lets see who else has a way besides u guys.

[beerock]

this isnt a belief this is fact