Yamaha YFZ450R Top End Rebuild | Partzilla.com

This is how to rebuild the top end on a Yamaha YFX450R. Find the parts for the whole job right here: bit.ly/YFZ450R-top-end-rebuild.
A top end rebuild on an ATV is a big job, and John will take you through it step-by-step.
DISASSEMBLY - 1:58
The plastics have to come off first. Then, we’ll remove the gas tank and the exhaust on our Yamaha ATV. Once we get those parts off, we’ll start tearing the engine down. John will show you how remove the valve cover and find top dead center. Once we do that, we can remove the cam chain, the cams, the head and the piston.
TOP END REBUILD - 12:34
Taking apart the top end is one thing, but rebuilding the top end on our Yamaha ATV takes a little more skill and the right parts. We’ve got new rings, and we’ll show you how to correctly position them on the piston. Then, we’ll connect our piston and set the table to install a new cylinder. After that, we’ll work on getting the head in place along with getting our timing chain on and setting the timing. Once we’re done with that, we’ll get some fire into our Yamaha ATV motor by replacing the spark plug.
PUTTING IT BACK TOGETHER - 30:15
With the top end put back together again, there are a few more thing we need to take care of before we start breaking it in. We’ll show you how to install the airbox on your YFZ450, and then we’ll get the exhaust back on. Our ATV won’t run without gas, so the next step will be to get the fuel tank bolted on and connected. Then, we’ll crank it up to make sure it’s working and get the plastics back on.
Doing the job one bite at a time? Watch our 3-part series on how to rebuild the top end on your Yamaha YFZ450 to see disassembly, the rebuild, and reassembly: • Yamaha YFZ450R Top End...
Or see the part of the job you want:
YFZ450R Top End Rebuild PT1: Engine Teardown:
• Yamaha YFZ450R Top End...
YFZ450R Top End Rebuild PT2: Rebuild:
• Yamaha YFZ450R Top End...
YFZ450R Top End Rebuild PT3: Reassembly:
• Yamaha YFZ450R Top End...
Read more about our top end rebuild project here: www.partzilla.com/blog/yamaha...
VIDEO HIGHLIGHTS:
Removing plastics - 2:00
Removing the fuel tank - 2:15
Draining fluids - 2:45
Removing exhaust - 3:20
Removing the airbox - 4:00
Disconnecting the radiator - 4:40
Removing the spark plug - 5:20
Removing the valve cover - 6:55
Finding top dead center - 7:30
Removing cam chain and cam - 8:50
Removing the head - 10:15
Removing the cylinder - 11:00
Positioning piston rings- 13:50
Connecting the piston - 15:10
Installing rings 16:22
Installing new cylinder - 18:45
Replacing chain guide - 20:31
Installing the head - 21:00
Setting cam timing - 23:00
Installing cams - 23:45
Installing the chain tensioner- 26:45
Installing new valve cover - 28:30
Replacing the spark plug - 29:45
Connecting the radiator - 30:24
Installing the intake -32:30
Installing the exhaust - 34:00
Installing fuel tank - 35:00
Refilling cooling system - 35:40
First start - 37:00
Installing plastics - 38:30
Find thousands of Yamaha ATV parts here: www.partzilla.com/catalog/yam...
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In the video we’re working with a 2009 Yamaha YFZ450R, but you may have similar steps for your Yamaha ATV. If you’re not sure whether these steps apply to your machine, leave a comment and we’ll get back to you.
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[@user-ck3ud3kp2w]

Great video and clear step by step details, just one more word " PERFECT " ... THANK YOU

[@raeesstemmet9656]

Great vid. Keep them coming

[@FLYBOY123456789]

i have no idea why i watched this...however, if I ever needed brain surgery - I would call YOU...extremely well done.

[@jamesquinn116]

the man ..nice and looks easy but thats yearz... of knowing what ur r doing.god bless u buddy . great video..

[@mxthunder2]

I always put the rings on the piston before i put the piston in the motor. always put emphasis on how important it is to make sure the gaps in the cir clips are pointing straight UP or straight DOWN.

[@scp8412]

amazing explanation! Thanks

[@Farcasstudio2000]

Nice video , keep going 😎

[@KelleyCycle]

At 11:34 he gets extremely lucky not to lose that cylinder dowel down into the crankcase.......amazing he doesn't even realize it's sitting there on the edge while talking about the piston...haha. Musta been his lucky day ;) Good video all in all.

[@rickeberline3673]

Truthfully that would be easy to get with a magnetic extension with the grab arms it's the cir clips that is the issue or the cam guides

[@garyshay6674]

ATF and coffee filters to clean the cylinder bore.

[@yamaanshaikh4780]

Excellent Job JOHN Sirrr....👍

[@mareksumguy1887]

Actually no... he failed miserably. He let a fresh engine (new cylinder and new piston rings) idle for WAY too long. In other words... he completely messed up the break-in process. This engine will never make the power it could have made. It will also burn more oil than it otherwise would have... had he broken it in properly. How a new engine is operated (after its first start) is very important. You start it and let it idle for only about 20 seconds... just enough to get everything lubricated. Then you put it under LIGHT load (ride around in 1st gear only... with light throttle/load... until it reaches operating temp). Then... staying in 1st or 2nd gear you do FULL THROTTLE runs all the way to redline... and then chop the throttle and let it overrun back down to low revs. The overrun (engine braking) helps seat the rings so as to get proper oil control. The full throttle runs to redline help seat the piston rings against the bore while the cylinder is still sufficiently rough enough to be able to do so. By doing this you are essentially grinding the rings and the cylinder bore into conformation with each other... so as to get the best seal (compression) between rings and bore. This is how it needs to be done. Go to mototuneusa for full explanation.

[@darklorddylan1316]

@@mareksumguy1887 That's not really approaching accuracy. From all the testing I've seen. Engines broken in with different methods have no measurable difference apart from one test I've seen where the top ring end gap varied by 5 millionths of an inch.

[@mareksumguy1887]

DarkLordDylan ... you talking about MC Garage??

[@darklorddylan1316]

@@mareksumguy1887 Yup, they were the only ones that found any difference whatsoever.

[@fwflyer78]

Nice work John!

[@jeremycarpentier122]

Do you have a video for a water pump rebuild? I also did the rebuild buy my self and around 15 hours later the water pump cover have broke and the coolant is leaking by there.

[@robertlikens6614]

I got an 01 yz 250f I got it an it was allready apart got new cams for it an ther is three dots one them do u just use the one on the outside of each cam to time it

[@ShawnDickens]

Doing it the hard way.

[@richardeberline3585]

If I put new hot cams it recommends not to let it idle so if I put a new top end so do I do the first heat cycle for 5 minutes still

[@Ducktruckful]

question? do you have to make sure that all the slack is out of the non tensioner side? of chain? on some brand motors if you don't ,when you put adjuster in, the cams will rotate & be out of time one tooth!

[@syednurnaim4800]

Hai brother you are the good education

[@filipelimalima2002]

Hello this video is very explicit and helpful However I have just one question Is the torque sequence used on yfz 450 2009 the same for yfz 450r SE 2014?

[@mastermattk]

Will the quad even fire and run at all if the timing is out or sync? I checked my 2003-4 honda trx450s 4x4 and the timing was 180° off from tdc but still runs. I just want to make sure because I was told it wouldn't run at all.

[@kimbletrainer3605]

How come no ring gap was measured when installing ? Is it not needed??

[@josantos4543]

Hi john.....I got a 14 ordered all eom cylinder head kit ..do I have to make any adjustments or just bolt on and play?!

[@chrisleon6222]

Can you do a crankshaft position sensor video need help with mine !!!!!

[@ianmangham4570]

WOW,had to replace the barrel

[@Drain09]

@partzilla do a banshee build!

[@eduardofigueroa2866]

How many pins should be in between the top cam dots? 13 or 14? I’ve seen both and idk what stock is !

[@KenpachiZarakiX]

I just wish partzilla didnt have so many things backordered. Great video!

[@ajmiller6874]

You Chbu

[@dogger2186]

Dry assemble....only oil the pin. Hone the cylinder, Dry Rings, Piston and cylinder....Once back together spray some contact cleaner into the plug hole and turn it over several times Start it until and idle it until it pukes coolant....let it cool and repeat one more time...done. No break in at all. Try it and on the next topend you will be surprised how good the piston looks after 80 hrs......no oil to burn off and carbon up

[@segura457]

Como busco el tiempo ,cuando cambio la cadena de distribución

[@TECIXV]

Have you heard of having to re torque the head after being broke in?

[@sinistercat-jm4lk]

No air filter cleaning either?

[@bretlange969]

it doesnt matter where you put the ring gap... the rings rotate lol. Also break in happeneds almost instantly so be hard on it right off the bat! otherwise the rings wont seal correctly.

[@jomby1231]

Wow. Great video. Still no way in hell I could do this job!

[@MH-re1cy]

Are you just doing this for information purposes or do you have an actual shop you work on customers quads? If so where is it located? I have a 2005 yfz 450 se that seized up on me cpl weeks ago while riding the dunes! I purchased a 2014 yfz 450r se next day from dealership so my trip wasn’t ruined! Now I have to fix the 2005 and the top end was done not to long ago that’s why I wasn’t to worried about buying it but I don’t think the oil upgrade was done to it. From what I found the 04-05’s had an issue getting oil to the top end and there is a aftermarket funnel type part you have to install that helps circulate oil through the motor!

[@anglegrinder4630]

How about this for a reciept?lol.....oh HES working on mine?(sips tea)

[@dhameeralmass8500]

Hi I am from Iraq and a follow on the alarm I like your voice that you do your job I have a question how How can I know the exact much turqe for any nut I hope you understand what I mean thank you

[@alexalex736]

how come you didn't check ring gap and file the rings?

[@armandoanaya3140]

How many hours before i need a top end rebuild om my 2016?

[@goncalofernandes7401]

Mecânich top

[@yourfavoritemailman450rida2]

I ha e so many questions my 2018 Yfz 450r doesn’t start an keep makin a buzz noise near the battery but My lights an neutral sign comes on but my gear shifter is stuff an will not move at all I’m lost

[@jasontoellner]

What would happen if the piston was installed 180 degrees?

[@marcomartin6325]

did you get all of the coolant drained or is it okay to mix the new style Yamaha coolant with what’s left in the engine?

[@PartzillaParts]

Try to drain as much as possible. You can mix some coolants, but just get the old stuff out of there.

[@destinhook3826]

is this engine similar to the Grizzly 450? i can not find any videos of a top end rebuild on my Grizzly 450.

[@PartzillaParts]

They are different.

[@jerjer-vy8db]

Hey there I have a question about the 2005 yfz450 they have a bad oil system so could i use a case cover from an 07 that already has the nozzle on my 05

[@jaded804]

jerjer 1990 run some duos

[@ryanhughes5731]

I have a 06 Yamaha yzf450 four-wheeler hesitates when it starts up but then it gets running it cuts off and I replace the starter what could that be if you can help me out let me know thanks

[@johnskaggs1951]

I have a Yamaha 700R special edition fuel injection. I paid a person $1500.00 to rebuild it for me and that person worked on it and I had my son test ride it and it wasn’t right so the person took it back to work on something else and he kept asking for more time and every time I contact him he put me off and needing more time to fix this has went on all summer and I had to take the Police to get my 4-wheeler back. I did get it back but it’s in peace’s. I’m 61 years old and don’t have a clue as to how to put it back together. I’m disabled and on a fixed income and I was honestly hoping you could help me with this problem of mine. If you would please give me a holler and let me know if you would be able to help. Thank you for your time and I watch your videos all the time.

[@averagereviews3389]

Sounds like neither did the guy you paid either. Small claims for the first guy. Then take it to an actual shop.

[@LuisLopez-uv9fw]

I have a YFZ450 too and I’m i think the same thing happened to mine but I’m not sure how do I know?

[@PartzillaParts]

Compression test to start

[@anglegrinder4630]

30:30 Why not replace those coils? I know the less you replace the better on these but im sure yamaha doesnt have crappy replacement stuff

[@michaelwoods761]

only thing i noticed,the original parts that stayed with the atv were all dirty, was there no shop hand that could have cleaned up the vehiclewhile it was stripped down? for me thats all customer service to allow them to leave the shop with a smile.

[@cristhianvizcarra1878]

Buenas noches una pregunta el piston y el cilindro de un yfz 450.del 2003 es igual que el de una yz 450 del 2003...

[@kingil4783]

??????

[@alinbaraiac1543]

Can I ask at 11:42 what you are referring to when you say “they” are stuck”? Thank you

[@joshuacastillo5952]

The piston

[@xocoyotl4]

The rings

[@kienzleboy12]

I’m fighting and fighting to put my cams back in it’s like I don’t have a long enough chain but it’s not bound up anywhere ugh it’s starting to piss me off

[@763GanderGuys]

Timing chain is stretched

[@kienzleboy12]

@@763GanderGuys if that was the case i would be experiencing slack in the chain with tension on it

[@Inkedup128]

this man said i aint cleaning anything that wont cause harm to internals unless im getting paid extra. lol

[@robertvalencia20]

Hello John, I Did A Top End Rebuild This Weekend And Follow Every Step On Your Video, But For Some Reason My Quad (yfz450) Doesn’t Want To Turn On, Has Spark And Cranks But Just Doesn’t Want To Start, Any Idea? Maybe The Timing Is Off? I Also Installed A Brand New Stator And New Battery So This Was My First Time Firing It Up With All The New Parts.

[@PartzillaParts]

Are you getting spark and fuel?

[@robertvalencia20]

Partzilla It Is Getting Fuel I Disconnected The Fuel Line On The Carburetor And Opened The Fuel Valve On The Gas Tank And Fuel Was Coming Out And It Also Getting Spark. Put In A New Spark Plug And Gapped It To Quad Specs.

[@PartzillaParts]

@@robertvalencia20 Do a compression check for valves, then check timing.

[@robertvalencia20]

Partzilla Retraced My Steps And Don’t Think I Top Dead Centered It Before Removing The Cams But Did Top Dead Center It After The Install, Not Sure If That’s What’s Causing The Problem.

[@robertvalencia20]

Also How Do I Perform A Valve Compression Test?

[@alejandromedina8963]

You’re guys have a shop in California?

[@PartzillaParts]

Not in California, but we have a distribution center out west. Depending on what you need, we can get it to you pretty quick.

[@koren.tomislav]

Hi, I really appreciate the job you did with filming all these operations. I just wanted to ask if the valve cover gasket is the same at 2007-2008 yfz450 and after 2009-... yfz450r? The shape is equal, but I don't understand the price difference. That's why I am asking this :) Thank you for answer.

[@PartzillaParts]

From your description, I'm not seeing a different part between the model years.

[@indicauk7421]

Why did I get so much shit suggested to me before this gold

[@jeremycarpentier122]

Thanks for this video! Where to get all the torque bolt specs?

[@stevenpoteat5311]

Owners manual

[@upurnose46]

watch the video

[@kirklandotto7276]

I don’t my rebuild and it seems to have a lot of compression anyone got any ideas

[@kirklandotto7276]

It seems to have a lot of compression like my starter motor hasn’t got the power to get it started

[@jjja_hyhh2078]

I have a 2014 and it's smoking blue smoke could it be a valve seal?

[@brokebikemtb4448]

Depending if it's at start up only or the entire time its running....valve seals usually only smoke during startup

[@sinistercat-jm4lk]

Why didn't you clean the carburetor? Great job, but I wonder if motor is going to be a 100 % without cleaning that carburetor!

[@jacobsilasi5323]

This quad is fuel injected so it doesn't have a carburetor.

[@deemmadeithappen1876]

At 25:04 ... what is the name of that part you’re installing?

[@sitandspin3762]

Cam towers or cam caps and the retainer clips

[@roosevelt7910]

what is the value of this engine cilinder?

[@ShadyOne9]

Skipped the hardest part! Getting that second circlip is a BITCH

[@blakem2028]

.

[@ofueru2219]

Where is your gimmick 😁

[@WICKEDGIXXERL]

That junk air cleaner didn't help...