proper break in?

I just got a new 02' yz426 yesterday and the dealer did not give me good info on break in. Any tips or suggestions. How did you guys break your bikes in? When should I do the first oil change?

Thanks in advance.

Just went through this myself for about the past 4 weeks. My dealer was lame also. I consulted some friends, but there are some peeps on this site that will have better advice than I.

I went through 3 short rides, or about 6 hours of ridding time, Being easy on the bike (or it was easy on me !!) I ran it through all gears gently to 3/4 power upto to the 3 ride when I ran it through all in full throttle (for short period of time)

Then I changed the oil just the other day (and yes you have to take that damn strainer out of the oil hose) , and if you need some oil changing advice and tips, just search this site, these guys know their sh%*t, and its not far from what the manual instructs. Thats just what I did, im sure others will have a more specific drill.

Im here in Ely, and a Former Vegas Dirt-Crasher

Aint nothin like a new bike :)

? Hey Vegas, do mind revealing the price of your new blue baby, just curious, cuz I did a buch of price checking in Nv and Ut. If not, no biggie. :)

dont get in the mindset of "oh, i have to break it in and be easy" just go ride it like you normally would, unless you're a desert rider that rides full open throttle :) change the oil and filter after about maybe 3 or 4 hours?

I have not broken in a new 426

All I know is this:

After I have ever built a new motor or Bought a new bike.

The first crucial hours is the hardest on the engine,

Steps I took after building Me RoadRacer and DirtTracker and Mount Bike and Play bike

1: Bring it home drool lots of drool

2: Bring her to a place to ride

3: Start her up let her warm up till you hand is getting nice and warm (Dont Touh Pipe)

4: Take for a very nice spin gently through the gears and back

5: Bring it to operating temp probably 20 minutes of ride

6: Stop park it until its safe to place your hand on the head.

7: Stage 2 Start , warm get on it let it run its pace for an hour or two

8: Bring home change oil, filter and clean strainer.

9: Stage 3 Bring it to the place it loves DIRT

10 Have fun Open her up let her breath

11: Wisper sweet nothings in her carb

12: 4 hours or one hard day of ride

13: change Oil Cleen Carb

Thats me and I am maticulis on maintaining a good motor. Oil is life :)

After That WFO and MAintain regular

Let the Flames begin

[ May 08, 2002: Message edited by: EgoAhole ]

Unibomber, you have private mail.

Thanks for the tips guys, I guess I am just being too anal about my new bike. But for what I paid I just don't want to do anything wrong to harm the engine.

The manual has very good and specific instructions on break in. The breakin time on this thing is relatively short.

I brought mine home Friday night, rode it around the field for 10 min. Parked it and when it cooled I put the Dr. D. pipe on.

Sat. morning loaded up, went to the track took an easy practice then went racing.

Sirthumpalot, my dealer gave the manual to someone else on accident. Didn't have one for my bike so they said to check in a week or two and maybe they will give me one. Lame

Freekin dealer, probably gave it to some guy buying a seadoo or something, those people can be such a-holes. Sales guys just eat at me, specially when they start talking as if they know what the hell they are talking about :)

I have been like most of you in the past, going very easy on the initial break in period, but a while back, this was brought up and was very interesting to me. It makes sense, but im not sure how I would do it. basically it said that the oil pressure pushes the piston rings against the cylinder walls, so when you break it in, keep the oil pressure up( by revving it higher). This will push the rings tightly against the cylinder wall, and seat them tightly in that spot. I am looking for the website that tells it in great detail, but I cant find it, when I do, i'll post it. Basically, the conclusion I have come to, is for the first 20-30 min, take it easy, change the oil, then ride it like you usually would.


My dealer (who owned a YZ 400 and WR 400 personally) told me to go about 10 hours on the break in. You shouldn't ride the sucker wide open for the full 10 hours, but other than that you don't need to baby it too much. After 10 hours, change the oil and filter and clean the screen (mine has been out twice and never had anything in it), but its always a good idea to check it. As far as oil goes, don't ask anyone for an oil pref or you will incite a riot among members :) . Just ride it and have fun with it, and tell the dealer to get you a friggin manual!

i think motor should be broken in by riding the way you normally do.if i build a motor to race i break it in racing,if i build a motor to cruise i cruise.ive had to rebuild topend between motos and break in was the ride from pits to starting gate.if motor is going to self destruct you really cant stop it.

Here is a link to chapters 1-3 of the '01 manual, I think the '02 should be similar (probably identical). Breakin and starting procedures start on page 1-14. Page 1-17 has the actual "Break In Procedures" section. Each page is a bitmap nammed with the page number. Hope this helps:

'01 426 Manual Chaptuers 1-3

PS-> For those of you waiting for the whole thing, I've started scanning chapter 4.

[ May 09, 2002: Message edited by: sirthumpalot ]

Sirthumpalot, thank you very much for posting that manual, that is cool. :)

I rode it for the second time yesterday and gave it no more than half throttle. I think today I am going to go RIDE it today. I have to admit though, half throttle on this bike was not too shabby. The power is hard hitting and not what I expected on a 4-stroke. I have to admit I have been a 2-smoke guy for many years. I still have my rmx 250. Break-in on those 2-strokes is much more critical than a 4-stroke I guess.

Thanks everyone for the replys

The most critical part of breaking in a fourstroke is breaking in the camshaft. Thats usually done at the factory. The piston is fairly safe right after installation. The crank is a roller, so no worries there. And if the cam was a roller tappet, there would be not break in required at all, but its not. There are a lot of other things in a motorcycle engine that need to "mate" like primary drives and transmission pieces so it never really hurts to put an hour or so on it fairly easily. If youve got 2 tanks of gas on it, ride it like ya stole it!

Matt, I would really like to read that article if you can locate it. For the life of me, I can't visualize how oil pressure can push the rings against the cylinder wall. Rings are nothing more than seals between the combustion chamber and the crankcase. The ring circumference is slightly more than the piston and must be squeezed a little to get the piston/ring assembly into the cylinder. Properly sized rings have a definite end gap that is measured for for signs that the rings and/or piston has excessive wear and needs replacing. For oil pressure to push the rings against the cylinder wall, there would have to be forced oil from inside the ring groove outward. If I'm not mistaken, only the cylinder walls are lubricated and the oil is "wiped" by the rings.

"BREAK IT IN LIKE YOU ARE GONNA RIDE IT", The manual calls for what an hour or something easy, then you are ready to race!! According to the manual, remember this is a race bike....Frank

Hugh, I appreciate you advise but my dealer told me not to fool with the oil until I had about 10 hours on the new engine? I am really a confused dude at this point. :)

Vegas, PLEASE dump that oil ASAP! Just ask Boit above. He changes oil after every ride! These machines carry little oil to begin with and share tranny and engine oil. It is basically impossible to change oil too often. As you get to know these bikes you will find that yes they are reliable, but the high performance 4 stoke design requires mucho maintenance to keep repair bills down. Your oil at this point will be black / grey and will have the viscosity of water! Don't do as I and learn everything the dumb ( hard ) way.

BTW , get yourself a magnetiuc drain plug ASAP, the Ty Davis ones are the stongest. I now hope that you are totally confused and that we may be able to make you save some greif. :)

[ May 10, 2002: Message edited by: Hugh LePage ]

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