2 Stroke Break In Procedure

[Streetsquid]

My buddy just bought a new '02 KX100 and he was reading the owner's manual re: the proper break-in procedure and was quite amazed at how specific and detailed it was. He's new to dirt bikes but has owned lots of 4 stroke street bikes. His (and mine) experience with 4 strokes is that owner's manuals usually lean towards being conservative (for legal and other reasons I'm sure) when describing the break-in steps, but is this true for 2 strokes too?? Could someone please post a tried-and-true 2 stroke break-in procedure for us 2 stroke newbies.

Cheers,

 

[ride_red_15]

dont take it over 1/2 throttle for the first tank full. then do half a tank going up to 3/4 throttle. after that, dont rev it to the moon, but it should be good.

 

[jmics19067]

keep it out of sand or off of steep hill climbs them first two tanks also .
You want to try and avoid any harsh loads on the engine till everything seats .

 

[Jordy]

I also bought a new, out of the box kx100 last year, and my father, who is a mechanic told me not ot go half throttle for two tanks just to feel safe. audbviously he knew i wasnt going to go only half throttle for two tanks:) anyways, the first tank make sure to stay half throttle, even if its tempting to go more. On your second tank start half throttle, then work it up to almost full throttle. Then for the next two tanks dont rev it to high to be sure. I mite be over exadurating but i did this as my brake in, and now my KX is working great:)

 

[Yamman]

What I do is once I have rebuilt my topend I take the bike out for 10min. not going over 1/2 throttle. Then I let the motor cool completely. (Heat cycle #1) Then I Do that again for another Heat cycle. Once it has cooled I take it out for another 10min ride going up to 3/4 throttle and then let it sit and completely cool and that will conclude your break in process. (Heat cycles are critical in getting the ring to set right) I've done this on over 3 rebuilds and has never failed. It was reccommended to me by the yamaha mechanic.

 

[hot125mod]

it doesnt hurt to use a fan when its on the stand of course :bang:

 

[TonyJeske]

Yeah if your trying to blow it over :nener: It helps it cool down faster ,or if your dynoing. Heat cycles are by far the best technique. They allow everything to heat up to operating temperature and naturally cool down, which in turn seats everything properly. Running 5 tanks of fuel through it is defenitly broken in if you want to go that road for peace of mind but it is defenitly overkill. It should be broken in after an hour to an hour and a half. Make sure you warm it up at a stedy idle until you feel heat in the radiators/cases/cylinder, don't become a fog machine right when you start up, you'll have a lot more to worry about then, then just breaking in your bike.

 

[thorman75]

A guy I know (AJ of Service Honda fame) picked up a new KX from TUF racing in DeKalb Il. Got on the highway heading for Casey 3 1/2 hours south. Started the bike and had it running in the back of his PU. Drove 1/2 hour shut it off, drove another 1/2 hour started it back up etc. Got to Casey and let er rip.
The quick break in method.
But I agree the key is let it get up to operating temp and then let it cool completely. It tempers things,and lets the rings seat

 

[TonyJeske]

A owners manual has its ups and downs. It gives you specs, tells you how to clean for an air filter, break in procedures and so on. It can also waste a lot of your time ex:break in. Maybe he just wants to hear what works for others who have experience in those areas. I think if you are going to break in your bike according to the manual you might as well break in your lawnmower as well. They're just trying to make it last for two years and my guess is that if you partack in the facts and opinions that this forum has, your bike is going to be torn apart before then anyways so what difference does it make if they ask or not.

 

[oldguy]

The only addition I used in the past was instead of using our normal 32:1 fuel mix I richened it a bit to about 24:1 for the first gallon. I always changed the tranny oil after the 3rd heat cycle in case there were any metal shavings sloshing around in there

 

[snb73]

http://www.mototuneusa.com/break_in_secrets.htm

 

[matego]

SNB73, love the link. I took some basic performance engine building classes at Penn Tech. and that is what they taught us. Run it long enough to make sure you have oil pressure, no leaks, timing right etc. Shut it off, put it on the dyno, recheck all fluids and run it like its going to be run...HARD! Besides, you dont see them breaking in engines at the drags. They slap them together, check clearances and tow it to the strip. (may be a bad example, nitro engines usualy blow up by the 1/8 mark :) )

 

[zewcrew]

My Honda manual makes it simple... During the first operating day or 15 miles avoid any full-throttle starts and rapid acceleration. I still start it and let it idle till hot then shut her down and check things over allowing it to cool down completely before actually riding.

 

[Moparman1539]

SNB73, love the link. I took some basic performance engine building classes at Penn Tech. and that is what they taught us. Run it long enough to make sure you have oil pressure, no leaks, timing right etc. Shut it off, put it on the dyno, recheck all fluids and run it like its going to be run...HARD! Besides, you dont see them breaking in engines at the drags. They slap them together, check clearances and tow it to the strip. (may be a bad example, nitro engines usualy blow up by the 1/8 mark :) )

Aint that the truth.... I went to a IHRA ring of fire night, and it had like 12 cars. I tink it took 2 hours to do those 12 cars (1 class.. Top fuel funny) Almost all of them broke.. spread oil on the track, and we had to wait for them to clean he track... But its a good thing my grandpap :whoa: was racing in the Sportman class.. Because i went to the motorhome, sat in the AC and listen to it on the radio...