Originally Posted by Wallrat
I've spoken with many old school engine fanatics over the years in regards to single cylinder motorcycle engines and the unanimous conclusion was to use dino oil during break in, then switch to synthetic. The idea is that dino oil allows for better wear in of the parts experiencing friction, particularly the rings. Everyone seems to differ on how they like to do break in and when you should change the oil over to synthetic so I adopted a marriage of several different theories:
Cycle 1: Start the engine and allow it to reach operating temperature while at idle. Shut it down and let it air cool to ambient.
Cycle 2: Start the bike and allow a brief warm up, then ride it easy in the lower-mid rpm range with as little load on the engine as you can manage. Avoid fast acceleration and whatever you do, don't lug it. Stay out of top gear and don't keep the rpms the same for more than a few seconds. Residential streets are pretty much ideal for this step. Ride for 10-15 minutes like this and then park it again and let it cool off to ambient.
Cycle 3: Another 10-15 minute ride while varying the throttle. Again, no top gear and avoid lugging it at all costs. This time you'll want light-medium power and mix in a short burst of acceleration every 30-60 seconds or so. I generally will hit WOT on the last 4 or 5 power bursts. Park it and while the bike is still warm, change the oil and filter. Again, stick with dino oil.
Cycle 4: Fill the tank and repeat this step until it's empty. Only ride for 15-20 minute sessions, and keep varying the RPM. You'll want some WOT but don't make the engine work too hard for too long. Whatever you do, don't lug it. The idea is to make the engine work at maximum output, but not overheat. Allow ample cooling time between fast WOT moments. Let the engine cool to ambient after each ride. After the tank is empty you need to change the oil and filter again using dino oil.
Cycle 5: Ride the bike however you want. Always avoid lugging since nothing is harder on the engine. Once you hit 1000 miles, switch to synthetic.
That sounds like a very sound break in procedure. Personally I just don't think you need to go to that level. I agree with everything except the oil changes. Change the oil at the first service and just ride.
The key point in your method is "the old school", so many things have changed, for the better since the "good old days". Better oil, better metallurgy, better manufacturing even on our 20 year old DRs.