This article is for everyone who has just bought a pit bike online and is wondering what to do after putting it together!
Most manufacturer’s manuals and other sources will tell you the same thing about running the engine for the first time:
Do not run your bike at more than two-thirds full throttle and avoid high RPMs for the first two hours of operation. It is often recommended to drain the oil AFTER these two hours and use a quality 10W40 4-stroke semi-synthetic oil.
Having just bought two new ssr pit bikes, I was browsing a very reputable pit bike forum (pitbikeclub.co.uk) looking for information on assembly and break-in and stumbled upon some VERY valuable information. This article is a short summary of a newsletter article I found written by Motoman. Motoman is a very experienced superbike builder who has his own newsletter (Power News Magazine).
This “Break-In Secrets” article is highly controversial.
“Links to this article now appear in hundreds of motorsport discussion forums around the world. The reason is that over time a large number of people have made a direct comparison between my method and the method in the driver’s manual. owner, and word of its success is spreading rapidly.
“The results are always the same…a dramatic increase in horsepower at all RPMs. Also, many professional mechanics have taken apart engines using this method, only to find that the condition of the engine is much better than when the owner’s manual owner The intrusion method has been used. What makes your page so controversial is that there have been many other intrusion articles written in the past that contradict what has been written here.”
Motoman wrote “Break-In Secrets” after successfully applying this method to approximately 300 new engines, all with excellent results and no problems at all. So I advise you to consider his advice!
According to Motoman, just by following the manufacturer’s instructions, you risk a permanent power loss of about 2 to 10 percent. The direct result of running in too smoothly will be leaking piston rings. This will allow pressure to flow into the crankcase during acceleration and draw oil into the combustion chamber during deceleration. In other words: loss of power and permanent contamination of the engine oil. The only solution to a bad run-in will be: rectify the cylinders, install new piston rings and start again. In other words… you will have to disassemble the engine!
You only get ONE chance to break in your engine correctly! I will explain why and how.
Proper break-in of your engine has to do with the piston ring seal. Proper break-in will result in a better fit of the piston ring against the cylinder surface. This will prevent leaking pistons. The new rings need to wear quite a bit to seal everything around the hole. If the gas pressure is strong enough during the first few miles of operation (open the throttle!), then the entire ring will wear on the cylinder surface to seal in the combustion pressure as best as possible.
So what’s the problem with a steal that’s too easy?
The polished hatch pattern in the cylinder bore acts as 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 is a very small window of opportunity to get the rings to seal really well…the first 20 miles! If the rings are not forced against the walls soon enough, they will use up the roughness before fully settling. Once that happens, there is no solution other than to reface the cylinders, install new rings, and start over.
SO… the best advice I found on breaking in your engine is
1) Run hard! (for specific methods: breaking into a dyno, the streets, or the race track… check out the 14 page Motomans article!
2) DO NOT use synthetic oil! Renew your oil immediately when you receive the bike, BEFORE you break it in, as you cannot be sure of its quality. Use Valvoline, Halvoline or similar 10W40 automotive oil. Change the oil and oil filter after the first 20 miles! After two days of hard racing you can switch to your favorite brand. Check out the article to find out why.