The Colorado Sportbike Club

We asked four top engine builders what they do to ensure peak power output and optimum engine life. Their answer:

If the wrong type of oil is used initially or the break-in 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, they're too slippery, if used during initial break-in 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 relatively 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, so 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 synthetic 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 with 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. It's that simple.

So that's it, sure is 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. For what it's worth, 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.

Posted 3/07/01 by thadr6racer@hotmail.com at the Alaskan Performance Bikes website (message #837). Click here to see the original posting.