Breaking in a Fresh Top End

[Exrider434]

Like the title says, In your opinion what is the best way to break in a fresh top end?

[NPelletier]

2 or 4stroke?

[KXRida]

do two heat cycles, then ride for 15 minutes trying to keep a constant load on it.

[Exrider434]

4 stroke, and what do you mean by heat cycles?

[KXRida]

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]

what do you mean ride with a constant load on it? sorry for all the questions first rebuild

[Keats]

giver hell. don't hold it at WOT, change the oil often right away and your set.

[KXRida]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

I'd still be rather skeptical of putting a fresh engine straight to the rev limiter.

[Aceman]

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]

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]

I'll still stick to my heat cycles. Got over 200 hours on a single ktm 250sx top end.

[Toadz400]

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]

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]

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]

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.