motor break in

[motocross169]

i am new to motorcycles. and i was wondering how this should be done for best engine life.i have a 2000 yz 125. i put in new wiesco crank and wiesco piston kit, and had cylinder re nikasiled. how do i break the engine in. and how often should i change the oil in the crank case.

 

[ellandoh]

technical answer ive had good results with is the heat cycle break in method and i change my oil after every weekend of riding for more technical answers........................................

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[brad m]

I would run it a little rich, and work the throttle. Don't keep it at the same rpm for long don't rev to high until you burn that tank of gas.

 

[motocross169]

what do you mean by the heat cycle break in technique

 

[brad m]

After you rebuild it and you are going to ride it for the first time you have to go easy on it and work the engine through out the rpm range but don't rev it to high. I hope that helps you a little better. Just do that for the first tank of gas but run it a little rich.

 

[whenfoxforks-ruled]

The search function seems to be back to normal!!!!! 2000 YZ. Is it new? I do not think so. Just the top and bottom ends. You do not need to get radical as a new bike break in. The heat cycles are very good. Heat cycle is letting the radiators get warm to the touch, bring the engine to normal operating temperature. Then let it completely cool down. Repeat. New I would do it on the stand twice, 2 short rides, 2 longer rides and done. Top and bottom end, less, once on the stand and 1 short and long each. Go over your bike while waiting, check the plug, coolant and oil level. Do you have fresh reeds and packing? Ratio about 32:1 or richer? Good pipe(no dents), clean also? Change the oil after break in, and every couple hours, if not sooner. If the main is correct, its broke in when it cleanly accelerates to the top. Too tight still, its like riding with brakes on nearly! Some of this opinion does depend on your particular ability riding and maintenance habits. Vintage Bob

 

[2strokerfun]

Lot of different opinions on breaking in an engine. But, as foxforks says, heat cycle method is arguably the most agreed on method (ya know, you can get away saying most anything by using the word "arguably" !!). Me, myself and I do this by running engine for about 5 minutes idle and low throttle repeatedly, not in gear. Let cool completely. Start it and run it again for 5-10 minutes idle and giving it throttle up to about 1/3 or so and back to idle repeatedly, still not in gear. Let it cool completely. Start it, ride it around slowly up to about 1/2 throttle for another 5-10 minutes. Let cool completely. Recheck torque on head and cylinder bolts (OK, honestly, I've skipped that a few times, but you really should). Then go ride it as you intend to ride. I always change the transmission oil after the first 20 minutes or so of actual riding after rebuilding an engine.

 

[whenfoxforks-ruled]

A half hour break in, leaves you 30 minutes closer to the end of your ring life. 5~7 hours? What does your manual say about the hours on the ring and piston? Are you keeping track with a compression gauge or hour meter? Vintage Bob