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Recommended engine break-in procedure

 Motorcyclist magazine asked four of the top engine builders in the country what they do to ensure peak power output and optimum engine life. This is most of the article, (all of the break--in procedure).

From MOTORCYCLIRecommended engine break-in procedure


Motorcyclist magazine asked four of the top engine builders in the country what they do to ensure peak power output and optimum engine life. This is most of the article, (all of the break--in procedure).

From MOTORCYCLIST Feb. 1991. titled GIVE IT A BREAK-IN (How to make your bike run stronger and live longer).

The first few hundred miles of a new engine's life have a major impact on how strongly that engine will perform, how much oil it will consume and how long it will last..... We ask four top engine builders what they do to ensure peak power output and optimum engine life..........piston ring and cylinder seating is critical to get a proper seal for power output and oil consumption.....If the wrong type of oil is used initially or the breakin is too easy, rings and cylinders could glaze and never seal properly. A fresh cylinder wall needs some medium to high engine loadings to get the piston rings to seat properly for good compression but don't lug or overheat the engine either. 
 Use high quality low viscosity oil (Valvoline 30 weight eg.) no synthetics, too slippery, if used during initial breakin the rings are sure to glaze. Initial run should be used to bring oil and coolant up to temperature only, with little or no load, then shut off and allow to cool right down. After thorough cool down (ambient temp), start up and ride under light loads at relativly low rpm 3000-5000 rpm, keep out of top gear, lugging is more detrimental than high rpm. Key advice, constantly vary load on engine, a constant load is not ideal for breaking in bearing tolerances. This run should last only 10-15 minutes before another complete cool down.

 The next run should be slightly higher rpm, 5000-7000 and under light to medium loads using short bursts of acceleration to seat the rings in early. Again 10-15 minutes of running should do it and again avoid top gear. Allow to cool right down. The third run should consist of light to medium engine loads with a few more bursts of medium-high rpm, 8000-9000 rpm max, and lasting just 10-15 minutes varying the engine load and avoiding top gear. Next while the engine is still warm drain the oil and change the filter. This gets out the new metal particles that are being worn away. Al Ludington from Vance and Hines feels most of the metal particles will break away within first 50 -75 miles, get them out soon after. To ensure the rings seat well, use same high quality oil and don't be shy about short duration high rpm blasts through the lower gears after the oil has been changed. A few more 15-20 minute sessions should be used to work up to the engine's redline gradually increasing the engine loads. After some definite hard running and 250-500 miles it's a good idea to check the valves. After 500 miles retorquing the head is suggested. Switch to snythetic oil but not before 500-1500 miles. Most of the engine experts warned of the danger of breaking in the engine too easily and ending up withwith an engine that will always run slow whether it is from tight tolerances, inadequate ring seal or carbon buildup. Engine load is more detrimental than rpm, so avoid lugging the engine but rev it freely especially in the lower gears. Muzzy summed up his break-in concerns most concisely: Basically, be sure not to get it too hot but be sure to seat the rings properly. Its that simple...........

So that's it, sure a lot different than keeping under 4000 rpm for 500 miles then under 5000 rpm for 1000 miles. Maybe bike manufacturers are being super cautious at the expense of your motor's performance? I think that they take the cautious route that works over time (1000 miles, or about 20 hours of break in) versus a faster route that can be more easily screwed up. FWIW, on the VF1000R, the slower break-in showed better leakdown at 4000 miles than at 1500, and I suspect that the go-slow method of the factory recommendations are looked at more for simplicities sake than for other effects.ST Feb. 1991. titled GIVE IT A BREAK-IN (How to make your bike run stronger and live longer).

The first few hundred miles of a new engine's life have a major impact on how strongly that engine will perform, how much oil it will consume and how long it will last..... We ask four top engine builders what they do to ensure peak power output and optimum engine life..........piston ring and cylinder seating is critical to get a proper seal for power output and oil consumption.....If the wrong type of oil is used initially or the breakin is too easy, rings and cylinders could glaze and never seal properly. A fresh cylinder wall needs some medium to high engine loadings to get the piston rings to seat properly for good compression but don't lug or overheat the engine either. Use high quality low viscosity oil (Valvoline 30 weight eg.) no synthetics, too slippery, if used during initial breakin the rings are sure to glaze. Initial run should be used to bring oil and coolant up to temperature only, with little or no load, then shut off and allow to cool right down. After thorough cool down (ambient temp), start up and ride under light loads at relativly low rpm 3000-5000 rpm, keep out of top gear, lugging is more detrimental than high rpm. Key advice, constantly vary load on engine, a constant load is not ideal for breaking in bearing tolerances. This run should last only 10-15 minutes before another complete cool down. The next run should be slightly higher rpm, 5000-7000 and under light to medium loads using short bursts of acceleration to seat the rings in early. Again 10-15 minutes of running should do it and again avoid top gear. Allow to cool right down. The third run should consist of light to medium engine loads with a few more bursts of medium-high rpm, 8000-9000 rpm max, and lasting just 10-15 minutes varying the engine load and avoiding top gear. Next while the engine is still warm drain the oil and change the filter. This gets out the new metal particles that are being worn away. Al Ludington from Vance and Hines feels most of the metal particles will break away within first 50 -75 miles, get them out soon after. To ensure the rings seat well, use same high quality oil and don't be shy about short duration high rpm blasts through the lower gears after the oil has been changed. A few more 15-20 minute sessions should be used to work up to the engine's redline gradually increasing the engine loads. After some definite hard running and 250-500 miles it's a good idea to check the valves. After 500 miles retorquing the head is suggested. Switch to snythetic oil but not before 500-1500 miles. Most of the engine experts warned of the danger of breaking in the engine too easily and ending up withwith an engine that will always run slow whether it is from tight tolerances, inadequate ring seal or carbon buildup. Engine load is more detrimental than rpm, so avoid lugging the engine but rev it freely especially in the lower gears. Muzzy summed up his break-in concerns most concisely: Basically, be sure not to get it too hot but be sure to seat the rings properly. Its that simple...........

So that's it, sure a lot different than keeping under 4000 rpm for 500 miles then under 5000 rpm for 1000 miles. Maybe bike manufacturers are being super cautious at the expense of your motor's performance? I think that they take the cautious route that works over time (1000 miles, or about 20 hours of break in) versus a faster route that can be more easily screwed up. FWIW, on the VF1000R, the slower break-in showed better leakdown at 4000 miles than at 1500, and I suspect that the go-slow method of the factory recommendations are looked at more for simplicities sake than for other effects.


 Any rebuilt or new engine has to go through a break in process. Each piece of moving metal must get to know and fit with the piece of metal it is moving against. Usually, the manufacturers put a sticker on the speedometer or tachometer telling you to take it easy for 600 miles or so. Your buddy says "If you want to run it hard, break it in hard." As you might expect, the truth is not on the right hand or the left but, in the center.
The problem is this. All this rubbing produces heat, which can cause oil to fail, which can cause a piston to seize to a cylinder wall. On the other hand, if there is not enough rubbing, the piston rings will not seat right with the cylinder walls. If this happens the engine will not reach it's full power potential. If the only new parts are piston and rings, as in an engine rebuild, we only have to worry about heat build up from the new parts. If the entire engine is new, the heat built up is even greater, because all the parts are new.
Yes, it is true that we have much better machining and quality control on new motorcycle engines, then we did in the past but, moving parts still have to wear in. If you have better, harder metal, it will take longer then if you have poorer, softer metal. Years ago I decided to bore my BMW motorcycle to the first oversize. After a hundred miles of break-in I started to ride normally, which is to say FAST ! Well, the bike just was not running right. I re-jetted the carb and it started to run OK. Another hundred miles passed and I had to rejet again. This went on for over one thousand miles. After the last re-jetting I realized I had just put the stock jets back in ! It took better then 1100 miles for those rings to break-in. The steel used in BMW motorcycles is very hard !
On one hand, if you run the bike too easy, you run the risk of the cylinder walls glazing over and then, maybe, never seating properly. On the other hand, if you run the bike too hard, you run the risk of engine seizure. I suspect, that even if you do glaze the cylinder walls over, if your run the engine hard enough and long enough, the rings will seat. However, this may take a thousand miles, or more, to do.
So what's a biker to do ? Well, a compromise is in order. This is what I do with a freshly rebuilt engine. It will work on new engines too. On a straight, deserted road, I put the bike in second or third gear and accelerate with wide open throttle to about one or two thousand RPM BELOW red line. I then shut the throttle and coast down, in gear, to two thousand RPM or so. I then do it again. I do this about ten times. Then I ride around for a while at an easy pace. I do this several times, if possible. This seats the rings without overheating the engine.
I would continue to do this during the entire break-in period. If you are doing any freeway riding. That is, running long periods of time at a steady throttle setting. I would also add this. Shut the throttle off and then on again, very quickly, every three or four miles. This tends to draw more oil up on the bottom of the pistons, lubing and cooling them. On a freshly rebuilt engine, I like to change the oil and filter at about two hundred miles and then every thousand miles thereafter. On a totally new engine, I change the oil and filter at one hundred fifty miles, three hundred miles, six hundred miles and twelve hundred miles. After that, change the oil and filter every one thousand miles.


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