engine break in

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cokecrazed007

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How do you guys break in a new engine, the procedue in the manual seems a little crazey. It say drive for 600km at no more thanhalf throttle and 400km at no more than3/4 throttle. Other people have said to just drive it like I would normally, but what do you guys think?
 
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sueandal

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good question i am going to follow this one. Start looking around the net because i found at least one site where the guy has a real convincing story about not taking it easy like the manuals usually suggest. He had all this data and pic. also dynos of same engines explaining how the easy old break in was the wrong way, you ended up with less power etc. I have no clue so just rode like normal (old iron cylinder non nickelsel ) when i rebuilt.:hr:
:) Al
 
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Squeege24

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I started with the "no revs over 5K" on the 09 KLR. I seem to remember a BMW mechanic saying not to "baby it but don't redline it", once. I've also read much of the article Sparklr has posted the link to, and that is very convincing. Soooo, last week, (at 400kms now) I started riding the way I always ride and that looks more like revs in the 6k range as I go thru the gears. And it just feels better.
DG
 
wjm

wjm

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That is a interesting site, I think I will go with his recommendations.

Bill
 
Sparkle

Sparkle

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My opinion is this is a big mistake. I've heard the theory too but it misses some important aspects:

1: Of course it's combustion pressure that forces the rings into close contact with the cylinder....2 stroke engines for years have used "Dykes" rings and tapered "lands" to promote the flow of pressure behind the ring. This part is true.

But combustion chamber pressures are exactly the same under all throttle conditions. Same mixture, same volume, same compression ratio, same pressure.......It just happensless times perminuteat lower throttle.

2: Two brand new machine parts fitted together for the first time will only touch each other in a few places until they have been run for a while. A brand new ring is extremely hard and sharp enough to cut you just handling it. When it's new, it may only actually touch the cylinder in a few spots, only sealed by the lubricant.

3: There is an upper limit to how fast you can slide two pieces of metal together...In a normal motorcycle engine at say 6500 RPM with a 3 inch stroke the rings are moving around54 feet per second...that's40 miles per hour! Remember it has to travel 6 inches each rotation...The speed isactuallyaround double that because the piston has to slow to a stop andreverse direction2 times a rotation.

4. At that speed the few points the ring is making contact with develop very high heat because of the low surface contact area...sometimes enough heat toburn through the thin layer of oil andscrape the cylinder bore. After the engine is broken in the ring is making full contactthe surface area is higher allowing high heat to flow better to the cylinder for cooling.

5. The thing that keeps this localized heat low on a brand new bike is by riding it at lower revolutions allowing time for the heat spots to bleed away.

If I ever get the chance to buy a new bike, I'll trust the guys that designed it...

But, then that's just me....:mad3:

Sparkle
 
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Cedartree

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The mototune method seems to be working just fine for me (so far), about 1000 kms now on a new piston/rings/hone job (DRZ 400S).Oil change after about 40km from mineral to synthetic. The oil is clean and thus far the engine has not used any oil that I can tell. Prior to the overhaul, it would burn 500mL in 300km of hard use. I also put the engine back together with NO OIL on the cylinder walls... as per the recommendations of a certain well known (in the DRZ Thumpertalk forum at least) Colorado engine builder. I was hesitant but the guy knows his stuff. The bike pullslike never before...So far so good.
 
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getoutside

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I rebuilt my dr350 to a 385cc and broke it in the motoman way. Also being doing this for years with my other bikes. I've never had any problems, never use oil and bikes always pull hard. This is like the great oil debate everyone has their opinions so go with what you feel.
 
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cokecrazed007

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I just broke in my engine and changed the oil after 30 km, I also pulled the oil screen out of the frame and flushed the oil tank out. I broke my engine the motorman way and so far so good. It pulls had and we will see if it uses any oil.
 
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aheath73

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Well, I just picked up a DR650 a few weeks ago and now have about 750 km on the odo. I have been breaking it in in a "middle of the road" kind of way...

I'll ramp it up on the highway, cruise around town, play in the dirt a bit, drive fast, drive slow, high and low RPM's...kind of like you're riding a bike! I haven't redlined it, but I haven't really babied it, either...I've had it WOT a couple of times, but not right away...and that was passing uphill at 120 kph...

I figure the most sensible break-in method, without following the precise motortune procedure, or the (in my opinion) overly cautious factory reccomendations, is to use it but don't abuse it...time will tell, I suppose. Good luck!
 
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Guest

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Ditto on that, I too just bought a DR650 and now sitting at 800K or so. I'm not hard on her but not too easy either, sorta easying her into my regular style of riding. I also changed the oil at the earliest possible oportunity(around 100K). I have just started giving her some short almost WOT bursts in the lower gears. Only time will tell if this is the right thing to do.

PS: just got the Happy trail panniers and they a pretty good for the money.
 
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tobster

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I bought my DR 2 -3 weeks ago, I took it really easy for 300k then did a big 600k ride at around 3/4 throttle. Then 200k of commutes, then the first service at 1100k. Im now up to 1700k in 2-3 weeks and I ride flat out pretty much everywhere on the road. Engine seems fine and feels completely predictable. More power would be good, but then the braking power will become an issue no doubt.
 
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