Proper 2004 WR450F break-in?

I'll have my new 04 WR450 in a couple of days. What do I need to know about proper break-in? How many miles is recommended for break-in? I'd appreciate any info. Thanks... :)

Hammer it hard!

There are two schools of thought:

#1. Baby it for 500 miles, never really revving it up, and letting break in slowly.

#2. Break it in like you intend to ride it. Another thought is to seat the rings well as soon as you can. The hone in the cylinder walls "cuts" the rings a smidge, and if you baby that cylinder, you won't be putting a full load on the rings while the hone on the cylinder is fresh.

I have never broke in a new bike, but if I ever do get a new one, I will have some nice fresh dino-oil in it, and I will flog the hell out of it for about 45 minutes.

Change out the oil, then I am off to the races.

I think the WR owners manual recommends a 1/2 hour break in period, oil change, then race.

Flog it!

I rode mine around the driveway for a couple of minutes and drained the oil and changed the filter. I went riding and that was it.

Before I went out I checked nuts and bolts, spokes and adjusted the controls.

Then do the free mods we all babble endlessly about and you are on your way.

Good luck and have fun on your new scooter.


just dont hold it at high revs for any amount of time.

keep in mind break in is only 20 min running time.

so fire it up, warm it up. and ride it around for 20 or so min. and yes, rev it way up. then change the oil.

Haven't the engines ran for a specified period of time and RPM before they get to us?

Break it in like you'll ride it.


Haven't the engines ran for a specified period of time and RPM before they get to us?

not form what i have been told. they are built {the engines} then slapped into the frame. as it rolls down the line, it is fired up to make sure it was put together properly. i don't even know if they run them up to full temp.


The manual has a break in procedure. Its pretty brief and painless and gives you a little time to get used to the bike before you really open it up. I followed the manual for break in (about an hour), then hammered it pretty hard. Its a great bike!

thanks everyone for the feedback on proper break-in. looks like I'll just take it really easy for the first few miles/hours

i havnt broken a bike in-in years.

in my opinion it doesnt benefit them at all.

for example my 03/R1

a friend bought his the same time as me,only difference he is a very pedantic fella.

he babied his for 600 miles

i on the over hand wrung its neck straight away.

i obviously changed the oil at the dealers as per the warranty specifies.

when it come to having aftermarket exhausts fitted, my bike made considerably more horsepower than his.

and the guy with the dyno laughed and said to my friend "run yours in did you?"

his reply to me is that his bike will last longer.

but considering the longest ive ever owned a bike in 15 years of riding is 18months.

i dont see that as a problem-my R1 is a much freer revving machine and is noticbly quicker than my friends.

ive done exactly the same with all my bikes including my 03/wr450 its making 51bhp when i had it re-jetted. :)

I just broke in 4 new yamahas.

They were all hard to start at first. I let them warm up before reving, (cylinder head hot to the touch). Now I have a little over 300 miles on the bikes and they all start right up. I putted around on some fire roads the first half of the day then I rode as normal. Changed the oil after a couple of rides. I think the most important thing is to allow the engine to come up to temp before hard reving. Different metals expand at different rates. One note on the water cooled bikes is you can warm them up too long. As soon as the cylinder head is hot I shut them down till I'm ready to take off. My TT125s (air cooled) take longer to warm up than my WRs.

The break in these days is to get the rings to seat. Revving it higher means more cylinder pressure. The cylinder pressure pushes the rings against the cylinder walls. The rings seat quicker. Fast break in, fast bike is not BS.

You are right. Break it in like you are going to ride it. Just change the oil after the first ride. :)

I have already done the airbox mod and removed the baffle. I own the Canadian version so I don't have to "cut" the grey wire or the throttle stop. Is it ok to break the bike in with the mods that I have done? If not I can just cover the holes in the airbox and put the baffle in.


Haven't the engines ran for a specified period of time and RPM before they get to us?

Break it in like you'll ride it.


Yes, according to the owners of mylocal Yammie shop, every engine is run on a chassis dyno.....ride it til it gets hot, stop, let her cool down and inspect for leaks(oil and water). After ~1/2 hour, or a bit more , fire her back up and ride.....

RIDE IT LIKE YOU STOLE IT! Not really but close. Check out for "engine break in secrets" A really good in depth analysis of breakin it in hard but correctly.

Well, I rode mine at practice last year before the TX GNCC for about 45 mintes hard. Changed the oil the next morning before the race and haven't looked back since. I probably change the oil way too much now but I'm looking for longevity. No problems with my break in! Just my 2 cents.....

I bought a new KDX220 back in 01 and the break in procedure was stupid! They said to warm it up for 10 minutes, let it cool down. Do this again, then after it cooled down, warm it back up, ride it for 30 minutes with modest throttle, no more than half. Then let it cool down, drain all the coolant, pull the head and cylinder, clean the carbon, replace the plug and reinstall the cylinder assembly. Of course, I didnt remove the cylinder at all. :cry:

I think most people on here are partly correct. The article mentioned earlier about flogging your engine in order to seat the rings is even correct, but is only half of the picture.

There are two important things that happen durring break-in:

1) The rings seat

2) The bearings seat

To properly seat the rings, you have to ride hard. Specifically, lots of acceleration and deceleration in order to blow/suck the fine particles out of the combustion chamber from the seating process.

On the other hand, when these bikes come fresh from the factory, their tolerances are VERY tight, and can cause some metal-to-metal contact. In normal operation, there should be virtually ZERO metal to metal contact, the motor oil should act as a protective layer between surfaces.

Durring the first hour or so of break-in, any hard riding that you do, CAN cause "gauling" or excessive wear in the bearings. If you ride MODERATELY for the first hour, starting nice and easy, then progressively working your way up the throttle durring that first hour, you will allow the bearings to wear more evenly. Then hammer it as hard as you can for the next hour. Go home, and change your oil.

Ideally, the "perfect" way to break in an engine is to ride it nice and easy for the first hour (or two) to seat the bottom end, then have your cylinder re-honed and ride the piss out of it to break in the rings...but most of us don't have the time or resources to do that. :cry:

Beef makes some excellent points above. I have only had to break in 2 motorcycle motors (04 WR450, rebuilt XR540), but I have done numerous car (mostly small block Chevy) engines so I used the same process:

Change oil as soon as you take possession of the bike. That way you know what is in there. I use a 10W-30 good Dino oil for this. Change filter, clean tank screen, add a magnetic drane plug (~$20). Again, now you know what's in there - you've set a baseline. Anything major happens (any chunks or big particles of metal on magnet or in filter), you'll know something could be wrong.

Start motor, 4 minutes around 2000rpm. Let motor cool for 1 hour. Ride bike, light and varied throttle for 10 minutes. Let motor cool for 1 hour.

Change oil again, same Dino type as above. Clean magnetic drainplug. Don't change filter - no need.

Ride for around 200-250 miles, moderate throttle, varied speeds. Change to Mobil 1 Redtop (15W-50), change filter, check screen and magnetic drainplug.

No other Mobil 1 is safe for a wet clutch.

Mobil 1 Redtop Oil changes every 12-18 running hours on the bike.

On this bike I change the filter every 2nd oil change, and check the mag drainplug every time. I consistently get a little gray mush on the drainplug. The particles are so small if you rub them in between your fingers it just feels like plain oil. It wipes right off, but always rub it all with your fingers to check for bigger pieces.

Amazing how little wear for so much power... I've lugged mine a few times where it's shaking and shuddering and making bad noises, but nothing show up broken, and the motor just plain RIPS.

If I can get the chassis dialed in half as good as the motor, I'll be a happy man. These stock tires just suck in the soft winter NorCal stuff right now. Switching to Michelin S-12's, a 52-tooth rear sprocket, and a stiffer 5.8kg rear spring, and putting in (finally) the JD Jetting Kit. Running a blueprinted GYTR tip in a stock pipe. I'm not as good as the motor is yet, but it's fun trying...


I definately agree with you on changing the oil as soon as you get the bike, and putting in a magnetic drain plug.

I would at least check the filter at your first oil change (after the initial 20 minutes of run-time)...I've seen a LOT of junk washed out of a fresh engine from the manufacturing and assembly processes. If you are going to go to the effort to change your oil, you might as well at least check.

This is the tried and true method for breaking in automotive engines, with many more moving parts and bearing surfaces, whose tolerances may not be as close as they should be. In a single cylinder motorcycle engine, it would break in the bearings great, but might be overkill for the bottom end, and might not be "firm" enough to properly seat the do both requires some compromise.

For the average Joe, starting out easy, then progressively adding throttle I think is the best compromise...but oppinions are like belly-buttons...everyone has one. :cry:

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