Motorcycle Top End Rebuild on Yamaha Four Stroke (Part 1 of 2)
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- Опубликовано: 8 май 2013
- If you need to rebuild the top end on a Yamaha four stroke motor, but you are not sure what to do, you are at the right place. Our detailed instructional video will walk you through how to rebuild the top end on a modern day WR250F motor. Watch our industry expert as he rebuilds the top end on a Yamaha WR250F motor. The steps shown in this video will be the same as they are on a YZ250F and the WR450F and YZ450F. Trust us to have the answers and instructions you are looking for. Get all your bike rebuild needs at www.rockymountainatvmc.com !
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You guys are life savers. I can't express how appreciative I am for these videos. They have saved me countless thousands in repair expenses. I'm not the best mechanic, and I need detailed, step-by-step instructions. No other how-to videos come close. So THANK YOU!
Not to mention you guys have the best deals, anywhere, for pretty much any part I need. Just ordered a carburetor repair kit and some odds and ends, free shipping, and it arrived the very next day! Awesome.
Keep up the good work.
Really cool to hear. Thanks so much. Happy Holidays from us to your Yz250f and WR! Enjoy.
Rocky Mountain ATV MC Ha! You even recalled what bikes I ordered parts for. That is attention to detail. 👌
I'm never going to shop anywhere else again. ✌
Haha, glad you liked that. We appreciate your business! Thanks
Probably best training video have ever seen, brilliant and thank you.
Never done a piston on a 4t before and been quoted 300 pounds just for labour, so I'm doing it myself thanks to your video everything explained perfectly
Awesome video ,very professional work ...well done
best toturial ive seen for this type of work
Thank you for this video RM , you guys are number 1
Best video I have seen yet!
marxxs Good to hear my man. Thanks for watching!
Great step by step video.
Thank You for this information
Thanks *Craig Krage!*
Very well explained , probably the best video I've seen on this subject.
Excelente, melhor tutorial!!
could yous possible do a removing carburetor and how to reinstall because ion wanna mess up my throttle cable
Could you make a video on how to use a motion pro degree wheel for timing a 4 stroke
These guys need to be famous
Thank you for this video
Awesome video was able to do a top end no problem relying on this video!!!! Thanks :)
kyle leon Great! If there's any other videos you'd like to see let us know!
Rocky Mountain ATV MC Any chance of a 2012 ktm sxf 250 top end rebuild? :)
@@rmatvmc this one comment was enough for me to subscribe !
Brilliant video.
Thank you.
One question, when you put it together, do you have to put the chain and rings the chain goes round in exactly the same position for timing? Or is all this set lower in the engine, so just a case of pulling the chain back up round the two rings?
(I'm a complete novice, but want to take this on on my bike with the help of your video)
Do you guys have yz 450 bottom end rebuild video. Or a video more in depth with the valves, you guys used a whole new assembly here. My buddy locked up his yz450 on the side the road today. Gunna open it up for him.
Great video.
Do you do boat or waverunner engines also? Thanks.
Great video! You mentioned that you have a valve replacement video as well. Can you provide a link?
We might in the future but there just isn't a whole lot of demand for that video. If you have your service manual and follow along with this video keeping in mind a few things will be different you'll be able to complete the rebuild.
Hey I removed my cam chain tensioner before losening the end bolt and it's tight. How should I go about getting it off?
Any vids on installing a auto decompression cam on a 2001 YZ250F.
Hi i have a wr400f and the motor broke down, i want to ask if all the parts except cylinder and piston is the same in the wr450f ? because i want to do an upgrade in the motor and go to buy the parts of the wr450f !!
awsome great video
Hey thanks +Christian Santos. Hope it helped out!
I am in the process of fully rebuilding the top end on a 2004 RMZ250 with all new parts including Cylinder Head, all valve components as well as wiseco cams etc. Beings I am starting with all new parts where is a good place to start on valve shim size???? Not sure where to start as the old ones are going to be WAY TO THICK?? I am going in the morning to get the proper feeler gauge set
Do you have to empty the oil and water before doing this or just the coolant
Hey my right crank case from my 01 yamaha yz 250f crack can you mane a video of how to replace it
Can i used this to perform yz426f top end replacement
Do you have a top end video for YZ450F 2014 and up?
Could you please do video on a top end rebuild for a kawasaki klx 300 thanks
My MT-07 is leaking oil at the head gasket. Is this the same procedure of disassembly and assembly? Thank you.
will carburetor cleaner work fine for cleaning it?
i guess i would not have to check the clearance to the rings since the cylinder wall was replaced 60 hours of riding before ? i bought a high comp piston to my 09 yz 250f
Tengo una duda que e desarmado un yamada wr250f y la bambú la del medio del eje leva de anmicion abre cuando aprieto
una pregunta, cual es el nombre de la herramienta que usan para pulir el cilindro?
Few questions :
-why you don't measure the piston to eventually re use it with new rings ?
-why you don't measure the cylinder bore and piston to see if you have the correct clearance ?
As i know you have to ,to be sure the new piston have the correct dimensions for your cylinder.
How does work the cooling system on those bikes ?
no thermostat,no cooling fan ?
the engine is running constantly cold so ?
My uncle has a 2002 Yamaha raptor 660r and one day we went riding and it started shooting oil out the air box, I've read some forums and heard that was caused by too much blow by or a bad piston ring, would a rebuild fix that? Please respond, thanks.
Is this an early top end rebuild by Skely ?
I need help with two WR250R dual sport bikes, is there a similar vid? Please also same for DRZ 400 - valves, top end,and bottom end rebuild videos DRZ400 & WR250R ( dual sport)
Is the engine basically the same on a ttr125? Or is it different since this bike is a 250
Is this the same top end rebuild as a 2015 wr450f
It doesn't have to be at TDC for disassembly.
How tight should the cam chain be?
I love the way you showed how to do this job. However I did all you presented and my bike doesn't start. Any idea how to troubleshoot it? I cleaned the carburator, checked the fuel pump, spark plug, air filter. All is fine but the bike still doesn't start. Please help if it's something you're familiar with. Thanks a lot
We most likely will in the near future but really the only difference between a fuel injected bike and a bike using a carburetor is the you would remove and install a throttle body instead of a carburetor and then you also have a fuel pump so you would have those wires to disconnect as well. Other than that the steps would be the same as this video.
would carb cleaner work the same?
With a service manual and referring to our Bottom End Rebuild Videos you should be able to get through it.
How long do you ride with this piston?
How many pounds are given to screws holding the head and cylinder?
Can you do a more recent Yamaha
hi, i have questions about my top. im rebuilding a yz250f motor since i blew my last one. after pouring gasoline on the valve seats, i found that some of my valves are leaking, and upon inspection i found damage inside most all the valve seals. is it sufficient to replace my valve seals or will i need to have my valve seats recut aswell?
Remove the valves, then inspect both surfaces for marks, clean All the carbon off the valve and seat (at its 45 deg angle and around) then try again..
If the old valve seat looks okay then get a new valve put some sharpy on the valve sealing surface and then put the valve in and turn it to see where the contact area is.
It should be about in the middle of the valve seats sealing edge..
Also inspect the valve guides while your at it :)
what radiators are on that wr250f?
does this bike have a cast iron liner?
Do I drain the oil when I do this?
I have a Kawasaki mojave 250 it's kick start and sometimes you can kick start it and sometimes you can't and sometimes it will go down half way and act like it's locked up and if I turn it over with a wrench it only goes so far then it acts like it's locked up to. it's as if its turning over then it suddenly stops can anybody help me out???
Hello !
I have a 2008 YZ250F with around 80 hours on it, and planning to replace the piston in the end of the season... What else is recomended to replace ?
When replacing the piston, do I have to hone it, or can I skip it ?
Thanks :)
steffen førnes When replacing a piston you will need to replace your gaskets so a top end gaskit kit will be needed. You can either save your old coolant into a bucket or replace it, depending on the condition its in? You can determine whether it's worth saving or not. To answer your honing question, i would best guess you are not going to see any cross hatches on your cylinder wall? I'd recommend you get it honed. The purpose is for oil retention and piston ring seating. Let us know if you have any questions, thanks for watching!
ok so I was riding my bike and all of a sudden I heard a click/ snap and then the bike died. I have no idea what happened, I fired it up let it warm up for a minute or so and then shifted into 2nd and took off. within 30 secs I heard the click/snap and now my kick lever is locked in position. any possible info would be helpful i haven't taken it to a shop and am considering selling the bike. ive only had it for one summer and am also considering rebuilding it myself or having a shop do it. any info on what yall might think happened would be appreciated and or price range on what a shop would charge....
Local shops vary in price so that is hard to say what they'll charge. The going rate i would guess would be $60-80 an hour at a shop. Depending if any real expensive parts got damaged inside would be the real deal breaker on whether to fix it or part out? I don't think you're out much attempting to fix it yourself.. just parts and more quality time in your garage lol. It's just a matter of diagnosing the problem and finding out what caused the lock up and what's all needed to fix the bike? As far as knowing what it could be, i don't know? I would start on the right side of the bike and work your way in. Assess the top end as well.. your timing could've jumped a tooth locking up the motor? Let us know what you find out, thanks!
Am I correct in seeing that there is no piston wrist bearing?
+Toshbar Yes, that's right. Four Stroke motorcycles do not have wrist pin bearings.
Can you do kx250 f
Guys how do I disconnect the motor from the frame of the yz450f? Do I have to remove the whole rear end from the frame of the bike?
UPDATE:
I went to my local Yamaha dealer service center and to get the engine off the bike the whole rear rack assembly and wheel has to be removed
*bomark 2002* You can leave the subframe still attached to the bike if you'd like? I like to take the top bolt holding the subframe out and then loosen the two side bolts, that way i can swing the subframe down and out of the way to move the motor around. With the swingarm you will want to take the top rear shock bolt out and you will need to pull the swingarm bolt that goes through the rear end of the motor and out the other side, then you can let the swingarm drop and hang there resting on your bike stand. This way you don't have to disconnect your rear brakeline. After doing this and obviously removing all motor mounts you should be good remove the heart out of the bike. Let us know if you run into any questions. Thanks.
Man I ended up takin it to my local shop I absolutely could not get that bolt out, I am having the bottom engine rebuild done to it, I ended up busting an eBay dealer on price and got a wiseco bottom end rebuild kit for $221 bucks, pricing error
Hi i have a question 2007 suzuki rmz250 i have a cylinder bore 83mm i want to know what i need to do with the cylinder head if i need port or valve and what cams i need i have hotcams stage2
I'd check with your local engine builder, or reach out to Race-Tech's engine department. They should be able to give you recommendations for porting, etc.. -Charles
How long do you say this would take? And once you do it do you get more familiar with doing this thanks! Great video👍🏻
You can plan on a good couple hours. The more you service your top end the more you become familiar with the whole breakdown process and steps to take to make the job go faster and smoother. If you have any questions during the rebuild process just let us know, we're happy to help where we can!
Rocky Mountain ATV MC Ok thank you very much! These are fantastic instructional videos! +subbed
Thank you very much!
Please get to work on the RFS ENGINES, From KTM 500 to 530, and instructions for regular Adjustments
could you go over how to take the clutch out please
If you are looking for a clutch replacement video follow this link Clutch replacement for motorcycle and ATV - Clutch kit Install ... If you are looking for instructions on removing the clutch stack along with the inner hub and outer basket just follow this link to our bottom end rebuild videos... Motorcycle bottom end rebuild part 1 (of 3) crank & bearings
Should you also replace the valves and stuff? how would you when you need new valves?
racequad9 Usually when your valves have stretched out of spec, bent, have excessive carbon build up that won't come off without damaging the valve and or the valve coating has started to come off. These are a couple signs you can look for.
Same as wr 426?
That banjo bolt.. would that be on my 05 yfz 450 as well and do you have to unscrew it?????
Yes, your ATV does have the oil supply line running up to your head. You would need to remove it when rebuilding your top end.
@@rmatvmc The banjo bolts have a horizontal hole in them (of course). Is it important to mark the bolts before removal, and/or take special care on installation, such that the hole is in a specific alignment to allow for oil flow during operation. (Yes I am so ignorant that I am basically asking you "how does this banjo bolt work?"... sorry... :-).
If you've never disassembled an engine before, would take the engine off the bike make it easier? or is that too much?
If your just doing the piston leave the engine in the frame
Easier
I have a 05 Yamaha YZ450F that will not turn over. It started with a bog/hesitation & pop sounds than shuts off completely. Values checked 100% and are good. Air filter checked and good. Fresh gas & oil, new spark plug, added a new fuel screw, cleaned carb 100%. Far as the top/bottom end is concerned in my opinion I believe they're all good because I don't ride it everyday or every week. I have a rebuild carb kit coming this week which I will install it just in case. Do you all think I'm over looking something that needs attention? Maybe the float is stuck or something like that!
Check to make sure the plug is getting a spark. Even if you replaced the plug, there might still be something wrong with the electrical that can keep it from making a spark. If you are getting a spark then it's probably carburetor. There is a small valve that the float moves up and down. It has a little rubber tip and if it wears (you'll see a small ring around the tip) the float will constantly get stuck and the bike won't get any gas.
+Jacob Phillipps Thanks, will do.
I'm sure you did, but did you turn your fuel screw to the right setting?
Would this basically be the same for a 98 WR400f?
Yes, you can definitely use this video to help out with the rebuild of your WR400. I would recommend having a service manual and watching some tutorials on that bike exactly to be sure there are no surprises. But this will cover most of the basics.
Should the cam lobe or lifting rods spin freely under the cam blocks
Soapy Bee Do you have your cam chain and cam chain tensioner on? They should rotate freely to a certain point and then they'll make contact with the shim buckets and stop. (if rotating by hand and cam chain and tensioner are off).
Yea she is all hooked up an back together
Soapy Bee Then no. If you have it all back together. It'd be tough to spin by hand. You can use the kickstarter carefully or the flywheel nut to turn the motor.
Excellent cheers for the heads up mate always find your vids helpful thanks
What about when you have the cam chain an tensioner is off an you just have the blocks or towers tightened down should they spin freely then
old piston looked fine other than carbon build up
Hey can anyone tell me if I can put a bottom end out of a 2003 yz250f into my 2001 yz250f??
james laRue You might be able to do a complete motor swap into the frame. But as far as internals parts go, from my research there's too many different part #'s from both of those years. Part #'s don't match up. I would check on some forums and see what others have attempted and see what they've needed to do.
I looked on thumper talk and they said yes but the only reason I wanna do this is I can't find any bottom end rebuild kits for my year bike but they have a lot of cheap 2003 yz250f bottom end kits
and con rod!
Would this also go for a 2006 yz250f that seized up from no antifreeze
Yes.
Seized up from no antifreeze? You are too stupid to own a motorcycle.
+Tec 9 no there was a broken bolt on the water pump and it leaked and plus it's my brothers
This the reason why I want to replace my wr with a 2 stroke
how many hours for shop top end rebuild yzf426?
It's just going to depend on the shop, you'd just have to call in and get an estimate.
My locating clip fell down to the bottom what do I do
You can either use a long magnet extension to get it out or take off the ignition cover (stator) and fish it out that way.
Isn't the cylinder nikasil plated? so it can only be honed with a diamond? i thougt you could throw the cylinder away if you use a hone like that.
+Mitchell HürenKamp The manufacture of the flex-hone states that it is safe for nikasil and sleeved cylinders.
+Rocky Mountain ATV MC Oke, maybe i confused it with the normal 3 stone hone, they can actually damage the nikasil plating (pulling chuncs of). I enjoyed watching your video anyway.
@@rmatvmc Hey folks, many years on and this video is still a gem, THANKS! Would you please post the specific Flex-Hone tool you recommend (perhaps a link to where to buy it on your site)? Or perhaps I should ask, am I safe to use any Flex-Hone tool that basically looks like the one you all used (e.g. can I assume that genuine Flex-Hone = safe to use?). Thanks again!
I visited your site. But i could not found own bike's piston kit. Can you help me i want to buy a new one 🙏
My bike is Yamaha WR450F
www.rockymountainatvmc.com/parts/dirt-bike-pistons?v=2003-yamaha-wr450f
Here you go.
Hello guys, i am from Slovakia, and i need rebuild on kawasaki kxf 250 year 2010, when we have video please send me, Thanks:)
Roman SK Nas Zdravie, Dakujem for watching our video man! We don't currently have a KX250F Rebuild video.. but you're more than welcome to follow the steps from this video to get the job done! Won't be exactly like your bike, but very close.
good video. can you please do one on a yamaha srx 3vn 400. will be much appreciated
+GAH - MENSAH GEOFFREY We'll see about getting this added to the list. Thanks
+Rocky Mountain ATV MC thanks brother
Contact cleaner...like WD40 or Carb cleaner?
Contact or Carburetor cleaner will get the job done. Thanks
Can you help me for find to my bike's piston. I visited your site but i could not found it (yamaha wr450f)
What year is your bike?
@@rmatvmc 2004
@@alikorkmaz995 Click the link below and you will see all the pistons and other engine parts that fit your WR450F.
www.rockymountainatvmc.com/parts/dirt-bike-engine?v=2004-yamaha-wr450f
Hope that helps!
@@rmatvmc I'm living in Turkey if I buy it can you send it to Turkey
@@rmatvmc help
Do a video with a fuel injected bike
What do u torque the cylinder head bolts to ?
Each Year, Make and Model vary on torque specs. We recommend you check your service manual to get your bikes specific torque spec for the cylinder head.
Great video, but you should fire the guy that did the subtitles
B Murf Yea, those are closed captions that RUclips's system puts in automatically. We're in the process of editing and timing all our videos. Thanks for checking out our video!
Another reason why I'm probably gonna get a two stroke
+Spike Spikus Less maintenance for sure.. but that 4 stroke power is like nothin else :)
Ain't really much to it. Only real difference is the valve train, can do a full top end rebuild in about 2.5 hours and a couple beers. No biggy. And my 4 stroke top ends last year's opposed to months with the 2 stroke.
If what's shown in the video is complex for you no way will you be able to rebuild your 2 stroke by yourself. Forget it.
How many hours does it take to do a rebuild roughly ?
William Kirsopp On a 4 stroke usually a couple hours, as long as everything goes smoothly for ya.
Can I
I want to like your guys company. But 50% of the time I've ordered from you guys I have had a problem getting my order in a decent time. Even an order I placed today. All of the items were in stock. I went to checkout. Selected next day air. all of the sudden, There's a problem with my order. It says. Some of these items are on back order. The order will ship when the items are in stock.
I'm sorry to hear this. Do you have an order# and I can have our CSR Team look into this for you? By chance did you have your items in your cart for a couple days and then you went back later to checkout? Please let us know. Thanks
should have said to set it to tdc before starting
It was in the top right caption of the video.
Hones cylinder then replaces it with new cylinder
Which of course is super helpful for those of us not wanting to replace our cylinder... this making the video even more useful...
You didn't show setting the timing of the motor before removing the cams
A little common sense and a service book go a long ways........
correct order:
1. remove accelerator cables
2. remove clutch cable
3. remove carburatore
4. remove full exhaust
5. remove radiator
6. remove engine put it on table
1-6 points will take you 30 -120 min . depending on your skill and experience
I am leaving this comment hoping that someone will reply and help me with my problem I own a 2006 YFZ 450 racing quad and it has several modifications done to the engine it has a Wiseco top end the upgraded oil pump and it has an aggressive cam in it so my problem is the quad wont idle you always have to give it a little bit of gas to keep it running or turn the idle up on the carburetor so we had taken it to a mechanic because I was too busy to work on it myself and he did a valve adjustment and he did work on the carburetor and he called me up and told me that the quad wont idle because it has an aggressive cam in it is this true if there's anyone out there with extensive knowledge can you please help me thank you
A big cam can definitely have an effect on the idle but you’d have to have a crazy early cam in it for the idle to completely drop off. If achieving a smooth idle or smoother running at lower RPM’s it may be easier to go back to a stock cam setup and dial it in from there. Do you know what stage of a cam is in it? Is your cylinder head stock? There is a bunch of different things that can have an effect on it but unless you take it to an engine tuner with a dyno it’s hard to tell exactly how it’s running and how to get it dialed in with all the aftermarket parts.
+Rocky Mountain ATV MC the cylinder is stock and mechanic all he said was it has an aggressive cam in it and it would have a problem idling and you really just have to give it a little bit of gas well it's sitting there to keep it running but I'm just worried about the mechanic charging me and not doing any work on it
DRAKE FORCE You may want to take it back to stock on the camshaft. Being a stock bore cylinder and no porting done to the cylinder? Could be you just don't need that mod done to your engine.
Well I will be racing it in motocross it is a full racing quad
pour qu'en des sous-titre en français??
If you click on the Transcript button below the video you can copy that and translate it to French
god thing i have a 2 stroke
Your video didn’t tell ppl where to have the timing marks at or how to properly remove the timing tensioner.
You will want to check your bikes service manual to set the timing and you can see us removing the cam chain tensioner at 2:52 in this video.
Thanks for watching!
Спасибо за видео, а с русскими субтитрами слабо?:)
how to ruin ur nikasil cylinder.