MotoUSA shows you how to rebuild the top end on a YZ125 two-stroke. We used a Vertex piston and Cometic gaskets. Always check your owners manual for proper torque specs. Subscribe: kzfaq.info_... Website: www.motorcycle-usa.com
Пікірлер: 333
@ehd19905 жыл бұрын
i used this video to replace the piston on a 2004 yz125. im mechanically inclined but have never been confident with getting into motors. this video helped me get passed that and now the bike runs 100% better. just wanted to say thanks!
@nathanmachado94125 жыл бұрын
Edwin D did you put oil on the piston and cylinder when you did it ? Thinking about doing mine and it doesn’t look that hard
@ehd19905 жыл бұрын
@@nathanmachado9412 my father in law did. i didnt want to but he decided to do it anyways and he applied a good amount. bike runs great. we used a wiseco piston kit that we got for 120. we also purchased the torque wrench tool he mentioned in the video, got it on amazon for 12 bucks. it was really an easy rebuild.
@nathanmachado94125 жыл бұрын
Edwin D thanks man, I’ve never done any work on a dirt bike like this before really, but it just seems to easy not to try!
@ehd19905 жыл бұрын
@@nathanmachado9412 no problem man. on the 04, the torque values were 22 ft lbs for the cylinder and 20 ft lbs for the head. good luck if you decide to do it. message me if you have more questions
@renevillarreal48075 жыл бұрын
Hey Edwin should I hone the top end on my rebuild?
@Sabian-7 жыл бұрын
"thats about as small as they come..... actually they come smaller." lol'd
@REKLUSE535 жыл бұрын
A tip for the torque wrench extension method. No formula required if the extension is at a 90 degree angle to the handle instead of 180.
@youtubechangedmyname5 жыл бұрын
First thing , wash the damn bike. Guy has sand sitting next to a open engine 🙄
@sivvinod31873 жыл бұрын
What happened to you guys? Your reviews were gold!
@MemeRider6 жыл бұрын
"Long overdue for a top end" 2015..... I got a 1993 that's never been rebuilt.
@jmbraap38225 жыл бұрын
Well the new bikes r made of plastic sooo
@youtubechangedmyname5 жыл бұрын
Just because it's never been rebuilt and still runs, doesn't mean it wouldn't benefit from a new top end. Also if you always putt around like a Grandpa then ya no shit. Try opening the throttle. I use to rebuild my YZ 125 every 10 races. I knew guys that did it every 3. Riding around your lawn for 20 years isn't riding.
@kyb42065 жыл бұрын
@@brandoncallioux9030 i have a 78 Kx never had a oil change and she still a winner
@Bananahammock885 жыл бұрын
@@kyb4206 well that's pretty dumb
@alexpearson76935 жыл бұрын
Don’t forget to leave the rag in the lock. It helps keep it clean
@DeAndre_20006 жыл бұрын
Whether it’s torqued to OEM spec or cross threaded tight is tight 🤷🏽♂️🤷🏽♂️🤷🏽♂️😂
@lilmarkbigs Жыл бұрын
It tight when it doesn’t get no tighter😂
@CarsnStuff7 жыл бұрын
Such an awesome video. I love watching stuff like this. miss 2 strokes. I really wanna get a cr250 !
@sherwinphillips33626 жыл бұрын
Review Guy love
@patledgard35188 жыл бұрын
Great rebuild video thanks for putting this up would love to see more tech tips from you guys.
@matiasdun65992 ай бұрын
I still miss you, Motorcycle USA
@wazzup29878 жыл бұрын
This video is so helpful! Thank you so much!
@martybass97272 жыл бұрын
I absolutely love yall!Yall explain perfectly how to fix bikes and I've that!Without yall on fixen bikes idk were I would start keep up the great videos!💯💯💯💯👍👍👍👍
@TS50ER8 жыл бұрын
Replace the top-end bearings every time as well. They are not expensive!
@alfred71368 жыл бұрын
+TS50ER I agree, can prevent allot of trouble.
@hayleighjackson90508 жыл бұрын
Y7
@kevinstearns41987 жыл бұрын
fukin rite!!!!!!!!!!!!!!!
@sciewter6 жыл бұрын
Normally I would assume he did but did not say. Those roller bearings do not give you much of a warning.
@Triumph20046 жыл бұрын
Why don't piston kits come with new small end bearing?
@ManuelTorres-qy8op4 жыл бұрын
Thanks I just did mine for the 1st time your video was helpful.
@vance123412345 жыл бұрын
Exactly what I wanted to see. Great vid. Thanks
@Mxrider92i5 жыл бұрын
Thanks a lot for this very helpful video guys !
@AverageDaveVideos8 жыл бұрын
Great video, I was curious how this was done.
@MsAbanob17 жыл бұрын
This is the best video I ever seen on rebuilding a top end
@MASincorporated7 жыл бұрын
The noob Mechanic ur profile picture is my screen saver
@upinsmokelol57598 жыл бұрын
brilliant video,plz do a two stroke bottom end rebuild video would be much appreciated :)
@wyattlarson11045 жыл бұрын
thanks for the awesome video and detail
@herbrachel97073 жыл бұрын
Fine job. Very good instruction too
@danny12threes65 жыл бұрын
good video for someone that doesn't ride 2 strokes but thinking of buying one in the future. The word rebuild kinda scared me whenever I'd hear you have to rebuild around 20 hrs or so for 2 strokes. But I have to say, the dirt that was centimeters from the inside of the engine was driving me crazy. Especially when you have a really clean shop and environment it would be best to make an instructional video with actually cleaning around the areas that are vulnerable to dirt or friction. My OCD was off the charts at the moment. but thanks for the video very helpful and now I know i'm capable of doing this in my own garage.
@Ricci___6 жыл бұрын
Very nice and educational video. Thanks!
@jefob6 жыл бұрын
Awesome video, only thing i didn't see explained was why rings need to be positioned properly so they don't pick up on a port. everything else was spot on.
@dny93944 жыл бұрын
It only goes in one way, there's a locating pin so ?
@GNX1577 жыл бұрын
Looking at the plug I don't think will give any indication of jetting at this point. Who knows how the engine was run for the last minute before shut down? You've gotta do a full throttle run and do an immediate shut down without idling then pull the plug and look at it. The other thing I noticed was, not much was spoken about looking at the top of the cylinder for a possible ring ridge developing, where the ring wear stops before the end of the cylinder. A new ring may hit that ridge and crack or cause other issues.
@dny93944 жыл бұрын
Good points and when does a top-end not include the Power Valve? They can cause a World of Hurt when they go wrong, and they do. Usually they are full of tar which glues everything together. Next time ok?
@adalbertosa83024 жыл бұрын
you did it very well. thanks
@garytauber4305 жыл бұрын
loved watching this video very interesting
@79brumley7 жыл бұрын
Excellent Video.
@rickeyaycock52542 жыл бұрын
Thank you for the info
@justinscott39998 жыл бұрын
Good demonstration
@Motorider1157 жыл бұрын
dont forget to put a taper on the exhaust bridge port holes on the piston, the oil will sit in there and prevent the exhaust bridge from wearing out as quick, learned that some someone that won the yamaha tech gp 2 years as well as many many things
@rickeyaycock52542 жыл бұрын
can you tell me more about this
@thecrazymanfromireland6 жыл бұрын
Super video thanks for sharing
@andrewevergreen91038 жыл бұрын
thanks! video about jetting for high altitude riding here in california?
@newagemuscle2010ss3 жыл бұрын
Great video!
@Knights2theEnd8 жыл бұрын
I can't believe you took apart the bike with a pile of dirt millimeters from getting inside.
@mareksumguy18878 жыл бұрын
+Knights2theEnd i know... what a dumbass.
@jonnoMoto8 жыл бұрын
+Knights2theEnd Meh, it's the crap above that's worrying.
@564Alanguiver8 жыл бұрын
when i know im gonna do a top end i clean the bike with the expansion chamber and muffler off the bike and stick the exhaust bung up the port to stop water, its the only way to get that tricky spot on yz's...
@rexburn19557 жыл бұрын
Dirty ass environment, and Oem parts are by far the best for Yamaha motors. You didn't hone the cylinder dumbass, how's the rings supposed to seat lol, and you didn't oil the piston skirts either, I know they are teflon coated. But still, and for teaching reasons this video is horrible! FAIL!!!
@mikebrown411827 жыл бұрын
oem parts is the best for yamaha motors. Do you have anything to back that up? Aftermarket pistons are often made to higher tolerance than standard oem and it depends on what kind of performance you want out of your engine or how it is tuned?
@covid83174 жыл бұрын
Great content thanks
@kevinstearns41987 жыл бұрын
wossner piston and rings and oem gaskets are the way to go.
@brianbranna95288 жыл бұрын
Great video
@ukdashcamz35805 жыл бұрын
If im ever fortunate to get back into moto x again i think id go 2 stroke. I actually prefer the more predictable instant powerband on a 4 but im fairly confident i could rebuild a 2 stroke and with a 4 i would not have a clue. Im surprised how simple that looked on the video.
@ryanlester7616 жыл бұрын
You don't souble-check the ring gap on the new ring before installing?
@7D2DROP8 жыл бұрын
great video
@markusdertomatenkopf53656 жыл бұрын
thanks you help me alot
@mudpro2007 жыл бұрын
what should be the break in procedure for this 2 stroke?
@bensnyder32393 жыл бұрын
Could you list the tools especially the size t handle for bolts?
@austinbirchall38574 жыл бұрын
I have the same bike with the same exhaust system should I rejet it it’s current stock jets and it feels like it has a big before power band
@sx150rider55 жыл бұрын
Do you have a link to the spanner that connects to the ratchet?
@MrDrSirGuyManJr6 жыл бұрын
Anyone know how necessary that power valve linkage spacer is? I lost it but it doesn’t look like it actually needs it.
@Shinobi1175 жыл бұрын
Can this go for 2 stroke race go kart engines such as the iame x30 125cc 6spd?
@mareksumguy18878 жыл бұрын
Make sure you spill a whole bunch of coolant INTO your crankcase!! 🤦
@cassiusashby287 жыл бұрын
+Marek Sumguy .both of yous shut up
@Damascus..7 жыл бұрын
ok i did what next
@mareksumguy18875 жыл бұрын
M.F.D Entertainment next, tip your bike upside down to get the coolant out.
@vPurii7 жыл бұрын
Any videos on how to rebuild top end on 2013 kx250f
@Rabbydabbydoo5 жыл бұрын
Great video. Not the usual video with techno or metal music crap :)
@sawyerwallace96316 жыл бұрын
If you use the crows foot at a 90° to the torque wrench it’s the same torque as normal if you use a crows foot.
@Ayeecole7 жыл бұрын
my power valve arm is not lining up is it bent or something
@yungshrimpeggfooyung6 жыл бұрын
Good video
@RelentlessCo7 жыл бұрын
I'm confident on everything but the power valve linkage
@gtrsquadboii39124 жыл бұрын
I have a 93 that needs new cylinder and piston and I'm trying to go cheap as possible any recommendations??
@aydenponto88087 жыл бұрын
very helpful
@sunnybuoy68117 жыл бұрын
Thank you!
@the_socompsp7 жыл бұрын
great video guys awesome job!
@daytonkarlson91813 жыл бұрын
2015 good end rebuild made 4 years ago problems about 60 hours on it still says long overdue
@Aprilpergar19756 жыл бұрын
I can never get the ring to stay in place... any tips?
@ripmax3336 жыл бұрын
so here's my question, lets say you pulled out the old piston and start to take measurements and check what piston you need A,B, C Whatever. you get a new piston and check the piston ring gap inside the bore. if the gap it's not within spec, what your suppose to do?
@jessearellanes6487 жыл бұрын
Thank you,
@rowena4907 жыл бұрын
Measure ring end gap, measure piston to wall. If everything's good they go right back in.
@Gavyn3077 жыл бұрын
Rowan Cranston yes. But i mean if you already have it apart, a piston is like 100 dollars so id throw a new one in while im at it, just my opinion.
@glockdude54726 жыл бұрын
Always replace it , it could eventually go and scratch the cylinder wall (sleeve). It's just not worth skimping on imo and in my experience.
@sciewter6 жыл бұрын
If the ring is worn out your piston is not far behind.
@aklaunch3 жыл бұрын
Did you put oil on the outside of the piston or on the cylinder walls? I have been seeing mixed reviews on this for piston ring break in.
@hitthatsubscribe6 жыл бұрын
Anyone know how long this will take first time rebuilding a top end
@mubaneamahoro32114 жыл бұрын
Wonderful
@SoldierDemps6 жыл бұрын
How much wed it cost me for one of these? To get done for me?
@quincythomas37497 жыл бұрын
So I'm getting a 2 stroke 125 soon and need to know how often I'll need to. Change the piston. I don't think letting it go till it locks up is the best idea
@ogbobbyjohnson71445 жыл бұрын
lol
@2wheelpeel6644 жыл бұрын
Compression reading before and after ?
@RelentlessCo7 жыл бұрын
4:25 that marking or it looks like scrapping against the walls there is that okay or normal ?
@clarkfishingride24993 жыл бұрын
Hello sir, where can we order YZ125 fairings in reasonable price? Watching here from Philippines
@martystevens39696 жыл бұрын
You should've put oil on the piston and cylinder. before installing them. There is a 2 cycle ring compressor set with a base adapter but that cyl. obviously had a taper at the bottom of the cylinder. If you could, maybe install oversize rings. I put .030 rings on or car and filed them to minimum gap- .008- .010 spec. I filed them to .008. It WORKED!! Why does it smoke? Maybe cylinder was worn. Always mic. the cyl. What did the owner say?
@A_Man_Of_Culture_8 жыл бұрын
Haven't posted a video in four months, I wonder what happened.
@matteo.bassini58197 жыл бұрын
The organization got shut down.
@soldozer7 жыл бұрын
Drug lords killed them.
@cl15143 жыл бұрын
well it’s been 4 years i don’t think there coming back
@conorhutch51686 жыл бұрын
Can anyone tell me why the cyclinder wasn't honed lightly before the new piston and rings where put in? I always thought you should lightly hone the cyclinder the create the best possible seal for the piston rings
@iracingrookie33015 жыл бұрын
Depends how much the owner was willing to spend I suppose..
@mareksumguy18875 жыл бұрын
Conor Hutch you have to understand that it is nikasil. You need a special diamond hone. Also, the piston and ring(s) wear before the crosshatch does.
@rideordiegoonies34714 жыл бұрын
because you don't wanna destroy the cross hatching on your cylinder
@JakeSmith-pr9wm3 жыл бұрын
Great video except for the fact you forgot to mention how to install the final Sirclip which is the most difficult part.
@bryce0993 жыл бұрын
So where is the best place to get gasket kits
@johnnelson33397 жыл бұрын
This is a very informative video. My son and I used it to successfully do the rebuild. You'll need a specialty tool for the torque as well as a torque wrench. If you intend to maintain a bike you should own those inexpensive tools anyway. Takes significantly more time than shown for rookies to complete. Take the extra time and clean things up real well. Make sure the head is flat before re-installation. Pay a pro for honing if necessary. The t-handle tools speed things up a bunch. Buy some and have fun. This project is not for a first timer - you'll need some mechanical know how.
@aaronyork61734 жыл бұрын
What kind of 2 cycle oil were you using?
@enduromotocross2356 жыл бұрын
Does anyone know we're I can get a front sprocket guard for my yz 125 thank you
@zachhughes900z6 жыл бұрын
Enduro Motocross 😂😂 autozone
@wordsbydavidray8 жыл бұрын
why are you torqueing the base nuts that way? do you know how a torque wrench works?
@marcokornfeld34457 жыл бұрын
bottom end contaminated with dirt , dyno test without an escape system for fumes. Great job!!!!!
@PvTNuclear7 жыл бұрын
Marco Kornfeld people like you make me hate youtube, always criticizing others work when you probably havn't worked on a bike in your life
@Community-Action6 жыл бұрын
A little dirt won’t hurt
@jordan_bmx64406 жыл бұрын
is that the last fuck?
@CR-rb2sr6 жыл бұрын
No thread lock for the cylinder jug?? Should you use it or not?
@dny93944 жыл бұрын
Opinion varies. I do.
@alexmh61317 жыл бұрын
wow is it really this simple? I've got a full rebuild to do on a RS 125, was gunna get a friend to do it but I might just do it myself. the top end any way.
@dny93944 жыл бұрын
Make sure you clean the Power Valve.
@Mr.Stroke03314 жыл бұрын
How many hours was on that piston?
@johnathanhimka6 жыл бұрын
Where did you get the piston?
@Alfsp15 жыл бұрын
Don’t you need the hone a tad the cylinder ?
@andyjonson97607 жыл бұрын
What was that you measured in the cylinder? A ring of some sort. I've never seen that in a cylinder!
@GNX1577 жыл бұрын
Andy Jonson that was the rings old and new he had down in there measuring with a feeler gauge. Use the piston to push it down in there so it's perpendicular to the bore. Measure at several locations along the path the ring travels.
@Gear1993Head6 жыл бұрын
No honing?
@mike3004068 жыл бұрын
blk plug wasn't ridin hard enough
@christophermoore19987 жыл бұрын
mike carr
@kellyronaghan55874 жыл бұрын
1:02 is me after a night of drinking lol
@maxdad054 жыл бұрын
I just found it odd that he talked about cylinder scoring due to not letting the bike get up to temp, yet on the dyno, the bike sounded cold
@ngurahpratyusadharmacretry7792 жыл бұрын
how are you motoUSA?? Long time no see :(
@upinsmoketd_23595 жыл бұрын
Passing a honer through the cylinder isn’t recommended before installing new piston ?
@MaliciousSRT5 жыл бұрын
Its a 2015 not a 1995, cylinder was fine
@adji28 Жыл бұрын
I like yz 125😍😍
@TS50ER8 жыл бұрын
@4:30 Look at all that dirt on the crankcase!
@abcdabcd89708 жыл бұрын
why you didn't put oil on piston?
@Community-Action6 жыл бұрын
abcd abcd- that’s what she said
@BourbonwiththeBoys8 жыл бұрын
should you lubricate the piston
@mareksumguy18878 жыл бұрын
+c needham Yes.
@KevinJohanssonkevinjohansson5 жыл бұрын
Would a 53.96 piston fit if the old one was 53.95?
@dny93944 жыл бұрын
You'd need to measure the cylinder/piston clearance. Spec usually less than 0.120 mm.
@marklowe74316 жыл бұрын
Take seat and tank off then wash bike. Lot of criticism on this thread but the video was very well done and all the tips dead right. Maybe people being ungrateful is the real prob.