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How important is the break-in on a 4-stroke ?

rightarm said:
jim-bob said:
Old theory " Break it in slow and it will be slow--Break it in fast and it will be fast / later
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You said it "THEORY" AND THATS ALL IT IS.
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Many people, including myself, would argue that there is some truth to this.

If you take an ultra high performance motor, like the ones in our sleds, and put put around at 5000 rpm at a constant throttle right from day one until the break in period is over and compare that to a motor that is broken in with lots of throttle variation, including many short periods of wide open throttle, deceleration and everything in between - it is the motor broken-in at 5000 rpm will be more likely to consume oil, have lower compression and be slower.

At the same time, if you take the same ultra high performance motor and run it WFO from the instant it first fires until the break in is over, it too is more likely to be an oil burner (if it doesn't catestrophically fail).

Personally I think Yamaha's break in section of the manual should be re-written. Many interpret it as put putting around at a constant 5000 rpm for 100 miles and then a constant 7000 rpm until 300 miles and this is definitely not a good break-in. Unfortunately the way it is written this is the most logical interpretaton.

In addition to what it currently says, the manual should specifically say going over 6000 and 8000 rpm for short periods of time (regularly throughout the break-in period) is advised for a good break. It also should state that prolonged operation at any constant rpm for an extended period of time should be avoided and that breif periods of acceleration followed by deceleration can assist the break-in.
 

The more I get involved with this debate, the more I realize something. I broke mine in to motoman's theory however there was one difference. I waited until about 500 miles (just after my first oil change) to actually hold the sled open for more than a few seconds. As a read more and more I realize that this is pretty much what the manual says. The bottom line is, vary the throttle, don't be afraid to squeeze it hard, but just not for long, and don't hold it open until you got some miles on it.
 
The *KEY* defect in the motune approach is as follows;
Recent Snowmobile Info:

Yamaha's break-in recommendation for the RX1 has been to idle the engine for 15 minutes.
Some owners found that the heat build up from doing this was so extreme,
that their taillight had begun melting (!!!)

Yamaha has since changed the recommendation to three 5 minute idle periods.

Why would Yamaha recommend a break in method which will prevent the rings
from sealing as well as possible ??

This is a good question ...
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Now asides from the melted tail light (where did hear that? Doo?) .... at least good for a laugh.... The 3x5 minutes is because there is SO MUCH FRICTION that 1x15 can cause the engine to overheat, which PROVES that this initial idle is critically important!

This guy's recommendation is specifically contradictory to the manual, and he ADMITTEDLY doesn't understand the manual's break-in procedure. This first 15 minutes of idling is there because you can damage your engine (burn your rings) by running it hard right away.
 
LazyBastard said:
Now asides from the melted tail light (where did hear that? Doo?) .... at least good for a laugh.... The 3x5 minutes is because there is SO MUCH FRICTION that 1x15 can cause the engine to overheat, which PROVES that this initial idle is critically important!

This guy's recommendation is specifically contradictory to the manual, and he ADMITTEDLY doesn't understand the manual's break-in procedure. This first 15 minutes of idling is there because you can damage your engine (burn your rings) by running it hard right away.
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Yeah he isn't exactly clear on this and I haven't convinced myself either way on the 15 minute idle thing so I've always done it (no melted tail lights either...).

My 4-strokes and buddies 4-strokes have always had the fan kick in and some have shut down during the 15 minute idle period (the manual does still say idle for 15 minutes, not 3x5 minutes).

I've noticed that with a fully broken in sled, after 15 minutes of idling the fan often won't even have turned on yet.
 
my father rx1 mountain was raced 660' drags when it had about 200 km on it and the thing is a ringer, im sure jackshaft will agree with me on that. seems to be much better than any others that i have raced and it doesnt burn a drop of oil. i have beat a short track 800ho rev from start to finish with it. :Rockon: he wasnt to happy ;)!
 
I did idle mine twice before running it. The first time it didn't make the 15 minutes, it ran for just over 10 and shut down due to the heat. I let it cool and idled it again for the full 15, then let it cool again before running it. I have since heard the dealer actually idles the sled as part of the prep. Once you run it just make sure you load up those rings real good!
 
we had a 07 grizz 700 as a demo quad on our lot, got the very first one off the truck and ran the bag off it. Its main purpose was to demonstrate power steering to new customers, and they had a couple acres to horse around on behind the shop. We literally beat the crap out of this quad, WFO from day one, every day. 400 ft wheelies back and forth, 3 minute smoke shows, it now has over 1500 hard parking lot kilometers on it, and it is incredibly more powerful and responsive than any of our customers units. In fact we get many customers complaining that their units dont perform like the one they rode in the parking lot. We recommend all our customers to follow yamaha break in procedure. my 2 cents
 
So is the idling good or bad? I have not had the opportunity to ride my Venture yet because there is no snow but the dealer idled it, as per their start up schedule, prior to me picking it up. I filled it up on the way home, put fuel stabalizer in the tank and then let it idle for quite a long time to give the stabalizer a chance to get through the system. It was probably a good 30 mintes. The sled never shut offf, the temp light did not come on and I don't think the fan kicked in. I stuck it on the track stand & would rev the engine a bit every now & again but not too high, maybe 3-4 thousand rpm. The outside temp was probably 5 or 6 degrees out. Now after reading this thread I have to wonder if this extended period of idling was good or bad or if I should do it again without the opportunity to actually ride the machine. The next question is since this is a 4-stroke why the worry about break in anyway? I have had plenty of ATVs, automobiles & motorcycles and have never worried about breaking the engine in. Obviously I don't abuse them and drive them in a 'normal' fashion so why the concern with the sled engine?

BTW - this is my first 4-stroke & I don't want to screw anything up.
 
My dealer calls it a "heat cycle". We let it idle twice on mine for atleast 20 minutes. The motor did not get hot enough for the light to come on.

In my opinion, let it idle for another cycle or until the hot light comes on then you should be good to go for the next series of break in procedures. The next series is boring, but I stayed in the recommended rpm ranges in the book.

I have no regrets.

You are doing fine! ;)!
 
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