FOLLOW THESE INSTRUCTIONS FOR INITIAL START-UP AND HEAT CYCLING!!

After careful assembly of your new engine, follow these important steps during initial start-up.

1. Make sure you have oil pressure. Twin Cam engines pressurize the oil first, then run it through the oil filter before it starts to lubricate critical engine areas. The very last parts to see oil are the cylinder heads; coincidentally, the heads are quick to generate heat and need oil for lubrication and to carry heat away from these critical areas. For this reason, we highly recommend using 5W30 motor oil for priming and initial fire-up. During assembly, prime the lower end with a new oil filter in place (fill it with oil before installation), and be sure to pour some oil directly on the valve springs and valve stems. Leave the rocker lids off until you have verified oil flow to the rocker arms. Before starting the engine, cycle it in short bursts with the starter (plugs out but grounded). Install rocker lids after you have verified oil flow to the rocker area. Without oil, valve and guide damage can occur.<o></o>

2. Start the engine in short stages (heat cycles). Perfect piston fit is a critical factor for engine performance and long engine life. An incredible amount of heat is generated between the rings, pistons and cylinders during initial start-up. It is at this point where clearances are the tightest and your rings, pistons and cylinders will meet for the first time. Follow the instructions below and you'll be rewarded with an engine that will last longer and perform better.

DO NOT ESTIMATE TIME - USE A WATCH

3. 1st, 2nd, 3rd and 4th fire-ups: These are very short run times! Each of these initial 4 start-ups should last only ten (10) seconds each at 1250 - 1400 rpms (just above idle speed). After each start-up, allow the cylinders to cool to room temperature. Don't rush it. Take your time. Your new parts need to get acquainted.

4. 5th, 6th 7th and 8th fire-ups: Run times increase slightly. Run these 4 start-ups at 1250 - 1400 rpms, 15-20 seconds each, with time to cool to room temperature between each time.

5. 9th, 10th and 11th fire-ups: With a fan blowing air at the engine, increase run times to 45 seconds each, again at 1250 -1400 rpms. Allow cooling to room temperature between runs, as before.

6. Next 2 runs: No more than 1-1/2 minutes each. Continue to use a fan, but don't neglect the cooling period. These first few minutes of run time are critical to establish cylinder and piston wear patterns and to protect the rings from overheating. Remember: pistons don't die....they are murdered! The absolute worst thing you could do is start a fresh engine and let it idle, while you kick back and watch it melt from the inside out.

7. Change the oil to 20/50 or 20/60 (hot summer). Now you can start the break-in
process while riding the bike. Make your first rides short ones, with adequate.
cooling stops along the way. Don't lug the engine and avoid stop-and-go traffic.
Pick a route that will allow you to ride at moderate speeds, while shifting
through the rpm range. Keep rpm levels moderate; increase them gradually
as you log on the miles. Since your new engine will generate significantly
more power, it will likely realize an increase in operating temperature. A
quality oil cooler is also a smart investment and is highly recommended.


Source: S&S.com

 

Excellent info. Proper heat cycling during initial break in period is crucial to preventing power robbing micro welding of rings.

 

That is overkill from an old thread. Here's the latest procedure from S&S and what we have used on mine and my buddy's new motors.

A. Initial start up. Run engine approximately one minute at 1250-1750 rpm. DO NOT crack throttle or subject to any loads during this period as head gaskets are susceptible to failure at this time. During this time, check to see that oil pressure is normal, that oil is returning the oil tank, and that no leaks exist.

B. Shut off engine and thoroughly check for any leaks or other problems. Let engine cool to the touch.

C. After engine has cooled, start up again and allow the motor to build some heat. Engine should be run no longer than three to four minutes. When the cylinders become warm/ hot to the touch (approximately 150) shut the motor down and let it cool to room temp. Follow the same cautions as for the initial start-up, and continue to watch for problems.

D. Repeat this procedure 3 or 4 times. Each successive time it should take slightly longer to warm up and you can increase the temp slightly each time (+10). You can be more liberal each time with the rpm, gently vary rpm continuously from idle up to 2500 rpm in the final cycle. Don't be too concerned with final carb settings at this time because idle speed and mixture cannot be correctly set until the motor reaches full operating temperature. The motor should not reach that temperature during these cycles. Do not allow engine temperature to become excessive. After the motor has cooled to room temperature for the final time you are ready to start the 1000 mile engine break-in process.

E. The first 50 miles are most critical for new rings and piston break-in. Engine damage is most likely to occur during this period. Keep heat down by not exceeding 2500 rpm. Avoid lugging the motor, riding in hot weather or in traffic. Vary the engine speed. Do not lug the engine. We recommend changing the oil at 50 miles.

F. The next 500 miles should be spent running engine no faster than 3500 rpm or 60 mph. Avoid continuous steady speeds, and do not lug the engine. Vary engine rpm. We recommend changing the oil again at 500 miles.
CAUTION - Lugging or running engine prematurely at sustained high rpm may result in damage to pistons and other engine components. S&S voids it's guarantee if engine is not broken in properly.

G. For the balance of the first 1000 miles the motor can be run in a normal but conservative manner. You can be more liberal with the rpm range and motorcycle can be operated at normal highway speeds. Avoid overheating or putting any hard strain on the engine: no drag racing, dyno runs, excessive speed, trailer towing or sidecar operation.

 

Never get the rings seated properly using those methods and will have a underpreformer no matter what type of motor your "breaking in". check out www.mototuneusa.com for "properly" breakin' in a motor. I was told by the guy who did my first motor as he was a old dragracer the exact same thing and motors are even making more hp now with new technology. If the motor isn't put together right in the first place you'll find out no matter method you use.....