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Best break-in technique for new YZ 250

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I have bought new YZ-F four-strokes and did the heat-cycle deal for their break in and all went well.  Now, I just bought a new YZ 250 2-stroke.  Is the heat-cycle deal with oil change before riding hard the right way to go or what would you recommend?

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Two heat cycles, and during the first ride take it easy for 10-15 minutes, varying the rpm. Then simply twist it for 100-120 hours till the next piston

 

This is my recommended method also on 2 smoke. On a 4 stroke you would ride it easy for the first 400 boring miles. 

 

 

Then you spank the living crap outa it. 

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Warm it up and ride!

 

 That sumbitch was meant to be raced right off the showroom floor. 

Edited by Muffintop
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I did a couple heat cycles with 15:1 ratio. Dumped the fuel and changed oil. Normal use after that

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This is my recommended method also on 2 smoke. On a 4 stroke you would ride it easy for the first 400 boring miles. 

 

 

Then you spank the living crap outa it.

Don't listen to this guy........ I use year old gas and mix it at 107.2:1, fill the tank all the way up, start her up then hold it wide open till the tank is empty or the motor blows, if the latter happened you did somthing wrong on the build, start over and repeat break in process.

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You could always do what it says in the owners manual.  Generally speaking, the engineers that designed the bike know more than people who like to argue about things like this on internet forums.

 

And just to throw one more method into the mix, I like to take a 30 min or so trail/woods ride for a break in.  Let cool, then ride at race pace.

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You could always do what it says in the owners manual. Generally speaking, the engineers that designed the bike know more than people who like to argue about things like this on internet forums..

Sometimes... I know I'm not going to oil my air filter with tranny oil, and I'm pretty sure I don't have to replace my Piston every 40 hours. The engineers assume the bike is raced and thrown away after a season...

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TT user "wiseco" used to be a regular on TT.   There still are times when we could use comments from the piston manufacturer where we are spending our money  - but he hasn't logged on for a couple of years.  I don't get it.

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Do not use a different fuel/oil ratio for break-in. Using 15:1 actually leans the mixture, and doesn't help.[/quote

Recommendation directly from Yamaha owners manual

Like I said, I would take some of their recommendations as just that - a recommendation. The engineers also insist that you use OEM pistons, and replace it at 40 hours. I do neither.

On roadrace bikes, alot of tuners swear by the "dry break-in", so everything seats very quickly. They don't care about longevity, they want it to make peak horsepower for a few hundred miles, and then they'll tear it down and repeat.

I personally (and i guess many others here) have been doing it this way for a couple of decades, and it's worked out pretty well. Oh, and I also used to wrench on bikes for a living (even did a few rebuilds on Jessica Patterson's bikes and some Daytona 200 superbikes), so i've been around the block. 

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Warm it up, check for leaks, take it around the block and make sure everything is functional. Load up and go to the race.

That's what I did last time anyway. :ride:

Edited by ubu

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Warm it up, check for leaks, take it around the block to make sure it shifts through the gears. Load up and go to the race.

That's what I did last time anyway. :ride:

You forgot the cool-down time when you're explaining to the cop that your neighbor called to report someone riding a dirt bike on the street exactly WHY you're riding it.

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You forgot the cool-down time when you're explaining to the cop that your neighbor called to report someone riding a dirt bike on the street exactly WHY you're riding it.

You have a point and it should be taken into account.

 

I don't consider puttering around for a couple minutes in a respectful manner to make sure everything is working properly before driving 3 hours to a race "riding on the street". My neighbors seem to agree. It's not uncommon around here to hear a bike from time to time. For some reason the guy a couple houses down does this seemingly every time he rides though. It's kinda weird. 

 

I reworded my original post. Sounded too much like "running through the gears."  It wasn't ripping down the street. 

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