Hello

I just got my YZ450F 2010. It's really a sweet bike. Im coming off of 2 strokes so I dont know too much about the 4 stroke break in procedure. The manual says go easy for about one gas tank, my local mechanic said to go easy for about 5 tanks. Any suggestions would greatly help. Thanks
P.S. I'm not one of those open it wide open to break her in kind of guys.

i would say dont touch the rev limiter for the first tank. after that ride like you would normally ride

i rode around mid rpms for bout 45 min changed the oil and filter then rode it like normal(reving high, hit the limiter a few times) changed the oil again then beat on it like it owed me money.

Don't go too easy on it or you will never get the rings to seat into the cylinder. You only have one chance at that. Do a search, a while back there were some excellent threads on this subject. Congrats on the new bike:worthy:

Just ride it and don't worry about it. I wouldn't listen to your local mechanic. It doesn't sound like he knows what he's doing.

fccman said:

exactly just warm the bike up then rev it all you want, let it cool down then warm it up and rev it if not the rings will never seat on the nicasil, btw modern two strokes have the same process. Remember the change the oil after the first few heat cycles.

thanks for the tips, i'll crack her open a little to seat the rings

Thermal cycling is the most important aspect of engine break-in. Run the bike through 3-6 heat/cool cycles where you're actually riding the bike until it reaches full operating temp, then let it cool completely and repeat. Do this 3-6 times and you're good to go.

varies the rpm, shift up and down

lotsa engine brakes, etc

it should helps.

congrats on your new ride.

thanks for all the advice. Now I have to wait for all this snow that's falling to go away to finish my break in......

excalibur174 said:

Five easy tanks would put you way over 10 hours, that's probably when they tell you to check the valves, re-ring etc. Your mechanics an idiot.
I really never broke in a new bike other than taking it easy to get a feel for it. That means I never over-revved or fanned the clutch for the first 30 minutes or so that I owned a new bike.

Someone already said it. Let the bike warm up for a good 2-3 mins and then just rev it as hard as you want. It's actually better if you do rev it up a bit so the rings seat. change oil after every ride and clean oil filter, do this for about 2 full tanks and then go to once every three rides then once every 5 rides and so on. Also do you guys know how much the factory revs them up before shipping them off? They hit the rev limiter like crazy! They do it so the rings can seat well.

Also switch through EVERY gear and give it a little stress on each gear-5th is easy, 1st you don't have too, you want to get the gears worn at the same time the first time.

In experience, I've done it both ways and the one where I took it slow had a shorter piston life. The piston I hit hard with had a clean look on the head after 50 hours and was still use able. The rings also had less wear then the other. So just goes to show.

Getting the rings to seat not only helps with piston life, but, also makes a noticable power differanced. I broke in my first bike, a 94 cr80 taking it easy. The engine ended up being a dog and the piston only lasted 30 or so hours. A year and a half lated I bought a 96 RM125 and broke it in at the dunes. That bike flat hauled and was still running strong when I sold it 3 years later.

ok im sold i'll open it up some, come to think of it I have opened it up on all of my previous street bikes and dirt bikes I just couldnt resist. I always thought i had done bad to the bike but actually it was a good thing. What's weird about the manual for this yamaha is the intervals they say to change the oil and filter. They say about 12.5 hours in between oil changes. I think that's way too long, besides you can never over change your oil.

I'd say change it after the first ride, and probably the second. Then every 3-5 hours on the hour meter, oil filter every other change.

Welcome to TT! Great info regarding the YZ 450 here, enjoy your new bike.

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