New outlook on breaking in new motors

[buzzurd]

http://www.mototuneusa.com/break_in_secrets.htm

[twincamzz]

Nuthin' new there. I've broke my last 2 motors in that way, both with good results. Last one had 45K on it when I sold it & no oil usage whatsoever. Of course there will be folks who will tell you that this method will ruin your motor, so decide for yourself. YMMV.

[Twolane]

This isn't a new site, it's been around for years.

Personally, I wouldn't break in an air-cooled engine that way. It goes against all the principles I've learned over the years. If it's what someone wants to do, however, go to it. Let me know how you make out.

[IBARider]

Well, It's been years since I've rebuilt a motor and I believe there may be a difference between a 'new' motor and a 'new' bike.  I think the factory runs the motor and then I know there has to be some runnin' before delivery.  Anyways, for the last two 'new' bikes I've picked up...

Broke '02 in kinda easy like owners manual said, but I ride kinda hard so it got some of that too.  It was going through a quart every 1500 to 2500 miles with 130000 miles on motor.  I ran hard alot.

My '08... I loaded it pretty good first 20-30 miles like the above reference site.  We'll see if it makes a difference in long run... I doubt it

[PoorUB]

Nothing new. I have been breaking in engine with similar methods long before I knew about the internet. Most people read to much into it and think you are going to go out and beat the engine, work it very hard and run the hell out of it. That is not what is said. Warm it up good, and put the engine to work, not beat on it, but don't baby it either.

I tore down a car engine a few years ago that was locked up, with ~50,000 miles on it. The owner had babied it from day one. Bought it new and wanted to make it last. Rings never seated, the engine used some oil from day one. Finally it carboned up so bad that the carbon built up on the pistons and seized the engine. I tore it down, honed the bores, (they were in spec), replaced the pistons, rings, and bearings. I put the engine back into the car and drove it myself for a couple days, then gave it back to the owner. The owner had a change of heart, and ran that car fairly hard for the next 125,000 miles with no problems, then traded it off with ~175,000 miles on it and still running good.

[tireater]

I posted this awhile back....Many informed people here said break it in like S&S does ...I broke my last build in this way...

[Flat Dog]

I've broken in 3 bikes by running the at up to 6500, and all are doing quite well with good compression. Goes against everything I was taught in mechanic school.

I do take it easy for the first 100, tho...altering speed.

[Ultrashovel]

I like to run a new engine moderately with variations between higher and lower revolutions for the first 500 miles or so. I don't see any advantage to running them all the way up when right out of the crate. to each his or her own, however. It's nothing to fight about. LOL.

[silvercab996]

I read that guy's site years ago.

His method will work for the most part on currently produced mass manufactured motorcycles, cars, etc. I however won't use it. The guy has a general understanding of what's going on but actually misses a lot and is uninformed on small critical details. When I read where he says the rings exert 5-10 lbs pressure on the cylinder, I stopped and closed the link. This is way off base, especially for the Japanese bikes he is mainly refering to in the article. He also stated he has tried his method on over 300 bikes. And also thinks there is something magical about his method compared to the more conservative conventional technique.

My guess is the guy worked for a large Honda dealer and installed the batteries, gas, oil, and got the bikes ready for their new owner. Just for fun he would rev them up to a dangerously high level to warm them up fast. Doing this often without initialy damageing a motor, he was able to come to his conclusion. BTW the Japanese have always used, especially Honda early on, extremely fine micron finishes on machined parts. The very fine tolerences contribute to rapid mating of parts running together and without damaging heat.

This was not true of Harley-Davidson in the '70s or even the '80s. If a motor was reved too high before being broken in, too much heat would develop and the piston would start dragging on the cylinder. Pretty soon metal transfer occurs and you have a collapsed piston. Piston slap and lethargic performance are a result. I've seen it for years and still see it today. It's especially prevelent on aftermarket big motors and conversions that produce a lot of initial heat with their large bores, high compressions and radical cams. It has nothing to do with the make of the parts, just physics.

Harley started getting it right, I believe in the late '80s or early to mid '90s. Most of the excessive heat from break in occurs the first time the motor is started and it's first heat cycle. Subsequent starting will still produce heat but it will become more manageable with the amout of running time generated. The first 50 miles is the most critical, then the next 500. High performance rebuilds are still critical for heat management because jetting or fuel parameters may not be correct, ditto for ignition timing. Also individual machining and fitting of parts may fall outside fine production tolerences.

As a builder of over 40 years, I perfer the conventional method, slow and easy.  The same way I break in a new pair of boots.

[PoorUB]

My guess is the guy worked for a large Honda dealer and installed the batteries, gas, oil, and got the bikes ready for their new owner. Just for fun he would rev them up to a dangerously high level to warm them up fast. Doing this often without initialy damageing a motor, he was able to come to his conclusion.

No where in his instructions did I read anything like this, so I don't know how you came to this conclusion! He stresses that it is important to let the engine up to operating temps before loading it, then making a few passes at lighter load, the medium load, then heave load, all while keeping the RPM at reasonable levels.
I was taught 30 years ago to do the same with $20,000 diesel engines. With less than 1/2 hour of run time we were running them at full load.with no problems.

[1997bagger]

I was also trained by major engine manufactures to run a diesel full load and not let it idle but when I installed my S&S engine kit, I followed S&S break-in guidelines (heat cycle). I felt if something went wrong, S&S would consider talking to me if I used their method.