This article concerns everyone who just bought a pit bike online and are wondering what to do after assembling it!
Most manufacturer manuals and other sources will tell you the same thing about running the engine for the very first time:
Do not run your bike at more than two thirds of its full throttle and avoid high rpm’s during the first two hours of running. Often you are advised to drain the oil AFTER these two hours and use quality semi synthetic 10W40 4-stroke engine oil.
Because I just got myself a two new ssr pit bikes , I was browsing a very reputable pit bike forum (pitbikeclub.co.uk) looking for some info on assembly and breaking in and I stumbled upon some VERY valuable info. This article is a short summary of a newsletter article I found written by Motoman. Motoman is a very experienced superbike tuner who has his own newsletter (Power News Magazine).
This article “Break-In Secrets” is very controversial.
“Links to this article now appear on hundreds of motorsports discussion forums from all over the world. The reason is that over time, large numbers of people have done a direct comparison between my method and theowner’s manual method, and the news of their success is spreading rapidly.”
“The results are always the same… a dramatic increase in power at all RPMs. In addition, many professional mechanics have disassembled engines that have used this method, to find that the condition of the engine is much better than when the owner’s manual break-in method has been used.The thing that makes his page so controversial is that there have been many other break-in articles written in the past which will contradict what has been written here.”
Motoman wrote “break-In Secrets” after successfully applying this method to approximately 300 new engines, all with great results and no problems whatsoever. So I advise you to consider his advice!
According to Motoman, by just following the instructions from the manufacturer, you risk a permanent loss in power of about 2 to 10 percent. The direct result from a too gentle break-in will be leaky piston rings. This will allow pressure to blow by into the crankcase on acceleration, and to suck up oil into the combustion chamber on deceleration. In other words: loss in power and permanent contamination of the engine oil. The only solution to a bad break in will be: re-honing the cylinders, installing new piston rings and starting over again. In other words..you will have to take the engine apart!
You only get ONE chance to break in your engine correctly! I will explain you why and how.
Correctly breaking in your engine is all about the piston ring seal. A correct break in will result in a better fit of the piston ring against the cylinder surface. This will prevent leaky pistons. New rings must be worn in quite a bit in order to seal all around the bore. If the gas pressure is strong enough during the first miles of operation (open that throttle!), then the entire ring will wear into the cylinder surface, to seal the combustion pressure as well as possible.
So what is the problem with a too easy break in?
The honed crosshatch pattern in the cylinder bore acts like a file to allow the rings to wear. The rings quickly wear down the “peaks” of this roughness, regardless of how hard the engine is run.There’s a very small window of opportunity to get the rings to seal really well … the first 20 miles! If the rings aren’t forced against the walls soon enough, they’ll use up the roughness before they fully seat. Once that happens there is no solution but to re hone the cylinders, install new rings and start over again.
SO…the best advice i found about breaking in your engine is
1)Run it hard! (for specific methods: breaking in on a dyno, on the streets or on the racetrack…check Motomans 14 page article!
2)DONT use synthestic oil! Refresh your oil immediately when receive the bike, BEFORE breaking in, as you cannot be sure about its quality. Use Valvoline, Halvoline, or similar 10W40 petroleum CAR OIL. Cange oil and oil filter after first 20 miles!! After two days of hard racing you can change to your favorite brand. Check the article to find out why.
Source by Jan Klaas