Honda Cr 125 piston / top end rebuild. A movie produced by Frez Productions

[@65elcamino283]

the simplicity of a two stroke is a refreshing thing to work on as a mechanic

[@Sean4685]

for people who want to save time. dont take the head off. unless the gasket is damaged or you are having compression problems there is no need, just slide the barrel out from the top and give it and the powervalve butterfly a good clean with carb cleaner/brake cleaner. great video by the way.

[@chrisclarke7698]

this is the best instructional video iv seen thus far

[@jangho9]

Chris Clarke Thank you! :)

[@SkyCandyVisuals]

+jangho9 I agree 2stroke engine porn for sure!

[@PaulBailey3]

+Chris Clarke maybe add torque overlays next time you edit, but GREAT video.

[@homiedaklown7912]

I agree. Step by step. All you have to do is rewind the video if you forget a step. Awesome.

[@blackisback74]

Great video the only thing that would have made it better is instead of musichave someone giving audible instructions as they're doing it

[@aleksas53]

I'm a very rough critic i would say and your video is flawless. Everything is clearly told what to do , the music and the camera angles just makes me happy watching this video! Thank you very much, I have a cr125 2004 frame, 2001 engine. Your video will help me a lot since my engine blew up and am going to rebuild it soon.

[@jeffgallo7880]

I was waiting for the way he installed the piston with the rings on into the cylinder. .he skipped the most critical part ...

[@nicown1337]

So much satisfaction watching this

[@TheGreasemonkey369]

there's a little bushing that should take the slack out of your governor to power valves linkage where the little pin is

[@420motoripper2]

I noticed that too

[@leontaylor6011]

you all probably dont care but does anybody know of a way to log back into an Instagram account? I stupidly lost the account password. I would appreciate any tricks you can give me.

[@demetriusronald7082]

@Leon Taylor Instablaster :)

[@leontaylor6011]

@Demetrius Ronald Thanks for your reply. I found the site on google and Im in the hacking process atm. Seems to take quite some time so I will reply here later when my account password hopefully is recovered.

[@dirtjones6838]

At 7:29 you are missing a washer/bushing where your power valve actuator arm attaches. Also put a rag below to block the pin from falling into the right side cover. Nice job on the production of the video.

[@2wheeledtents]

Bro you’re a life saver didn’t realize mine was missing it until now🫡

[@Minnesotoby]

It's my first time working on a cr125 and I was looking for a video to get some advice. I never thought that I would find such a well made and invormative one! Thank you very much! Now lets go get some oil on my hands ;-)

[@devanedwards5986]

I don't know why, but this video was extremely satisfying and mesmerizing to watch, and very educational! Thank you!! I'm going to go buy a CR125 for my daughter with a blown head gasket, and rebuild it! Better to do a teardown anyways buying a used bike, you never know how the previous owner treated the poor thing!

[@jangho9]

Thanks Devan! im glad you liked the video. I hope to start to make new videos soon. If i was you i would change the top end on a used bike that i dint know anything about. Its the best to be on the safe side.

[@evansbaseball05]

Thanks for helping everyone who is a do it your selfer. I bet this video has saved a lot of people a lot of money.

[@thegoldenman54]

probably the best rebuild video ive seen on youtube, very nice! faved

[@jangho9]

This is your lucky day! The bike in the video is an 2002 Cr 125 :) Im glad the movie helped you.

[@mtbridingog9083]

Frez Productions perfect my same year and model

[@aaronmc5296]

I have 1

[@damiens_wrld6558]

I watched this because i am having an issue putting the head over the piston because of the piston ring being a pain

[@damiens_wrld6558]

But you didn’t include it😂

[@jangho9]

@@damiens_wrld6558 You mean putting the cylinder over the piston?

[@socks2441]

my last rebuild on my 2001 honda cr125 was a pro x piston too, lol. nostalgia. i am currently a year or two into a very slow going project of completely rebuilding my bike. only initiated due to 3rd gear popping in and out. hopefully i will be finished in another month or two. i cannot wait to ride again. i need to feel alive. its been too long. work, sleep, work, sleep. i cannot fucking take modern life much longer without a bit of escape. 2 stroke heaven provides said escape. so damn good.

[@IAMSKILLZ24]

Why I love 2 strokes! So easy to work on!!

[@vinnygarner949]

Hi, @ min 7:24 you forgot to put on the flanged collar that rides on the tie rod linkage that connects to the exhaust valve. You just secured it with the cotter pin is all. I would fix that.

[@foxbodylover2668]

Vinny Garner was thinking same thing that hes missing that collar, but then again the bike might be missing so hes working with what hes got

[@cj599]

Was gona say the same

[@Dellwikzoor]

this was the best top end rebuild movie i have ever seen ! very good!!

[@bryce4ucla95]

wow this is by far the best instructional video i have ever seen period. I feel confident now that i have watched this video that i would have a descent idea of how to do this rebuild. Great video keep it up

[@stevefalls186]

great video just bought 87 cr125 to restore came across your video had to watch.

[@premixpeter1972]

I can't put my finger on why but this is deeply satisfying to watch.

[@willselwood3965]

really good video man, im doing a top end soon and this video has helped me understand how to do it way more, sick bike btw man!

[@t-roymccoy59]

Bruh I love u for this I’m 15 and I had all the parts and did it day by day it took me 1mouth and 22 days while I got off of work and school💯

[@waylonthompson1149]

Just to do a top end? I'm 13 work and ride my stuff it take me 20 mins o rebuild a top end

[@rawatson83]

thanks for posting this video. i have only rebuilt a 400ex once. trying to refresh my memory. getting ready to rebuild my rm250.

[@xPANICxREVx423]

Your bike look VERY clean and nice for an 02. I have an 02 YZ125. Long live 2 strokes!!!!!!!Braaaap

[@gwillmg]

good videos but why did you not clean the power value,

[@jimmadonna1436]

I was going to ask him about that. I was wondering if he did it and didn't film it. When they get stuck, the bike runs like crap and damages the cam spindle. It flattens it.

[@Catfish2255]

Professional..I had just picked up a 1982 Cr 125r.I have to say it's in very nice original condition.I am going to replace the piston,ring and top gaskets.Because of it's age and knowing it has tempered through it's riding hours I was told to put a very thin coat of good quality gasket permatex on them to ensure a good all around seal in case there may be any imperfection on the actual surface.I am not going to have it resurfaced on the head but clean it well and assemble..Any comment?

[@BoughtNotBuilt]

Always install the circlips with the gap facing either straight up or straight down. The force of 1000+ RPM will pop that thing out very easily. Otherwise, great video

[@luisashby4838]

This video really helped me when doing a top end rebuild on my cr 125... many thanks and keep up with the great vids!

[@motomanjf]

One of the best quality videos I've ever seen! Nice job man

[@Sms68]

This Video is Incredible. Great Job. Just installed my 1st Piston. Came out great..Thanks

[@jangho9]

Thanks! Im glad it helped you out! =)

[@StratosAsa]

Great video my friend!! My CR 125 it needs new piston because it got stuck. I believe that i can change it myself

[@jrisinlove]

Man, great job. Loved the song that went with the video

[@andrewmcwhirter6567]

I'm looking into buying a dirt bike, and was really unsure about 2 stroke or 4 stroke. After seeing how easy it is to replace the piston, I'm pretty much sold on a 2 stroke now.

[@blackisback74]

How do I know if my top end is bad? I was riding my bike yesterday and doing about 65 mile-an-hour when all of a sudden it started to slow down like it was running out of gas. I kept trying to feather the gas to keep it running with no luck. Finally stopped try to start it up again and it started but then immediately started running out of gas.so I parked it behind someone's barn and took about 20 minutes to walk back to my truck and by the time I got back to it I started it up and it ran fine again but instead of driving it any further I just loaded in my truck to not cause any further engine damage in the event it is something more serious. But how do I determine if I need to rebuild the top end

[@tylertrexler9579]

It's good to dissasemble the power valves because when you're starting new with a fresh rebuild, there good to clean because over time they build up alot of carbon and don't want to work properly which can have a huge impact on power and throttle response. That is where I went wrong years ago. I rebuilt my 02 kx125, but I never cleaned the power valves and it definitely didn't have the power it should've for a fresh rebuild because that really does have a huge impact on several different things.

[@Enginelife84]

Really nice video! Allot of effort and time put in to this and very helpful! Nice bike!

[@marshaledmondson2970]

What about the torque for the head bolts? And what is the break in time and steps for a new top end for this thing?

[@kyleguoin7801]

I just did this to my 93 cr 125 i had to have the cindler re sleeved . It's at 120 psi. Everything is set to stock on the carb . Runs but poorly is this due to a worn crank seals? .

[@antonisformulas9414]

jangho9 THANKS FOR YOUR VIDEO. AND YOU ARE VERY GOOD MECHANIC AND CAMERAMAN !!!! REALY HELP OTHERS TO CHANGE PISTON THEMSELVES. GONGRATULATION !!!!

[@dillyb0612]

This is going to help me a lot! im about to do a rebuild on my 96 cr125! great vid

[@iura9950]

good afternoon, I have Question, I want to change the piston, if I remove the piston, do I need to change the cylinder or not?

[@charliechucker]

also wanted to point out you have a single ring piston. there are also 2 ring pistons availabke. 1 ring pistons are preferred for race use but 2 ring pistons are preferred for longevity and non-race use. if your cylinder wall is scored or worn, or you just go big bore, you really want to shop around for a place to mail your cylinder for a proper bore and replating. Bore-Tech in Ohio is the one I know of in this region.

[@charliechucker]

lastly, I should add that if you put in an aftermarket forged piston, they require proper longer warmup times before getting on it hard. oem cast pistons should be warmed up properly before riding hard as well, but the forged materials are much more sensitive to thermal expansion/contraction, and it becomes even more critical to give the engine proper warmup time to get to normal operating temps.

[@coleeitel4861]

Double ring piston in a 2 stroke= more friction less power your way better off to runs single ring

[@backyardboosters9128]

chuck lambert I'm not aware of any twin ring pistons for 125's for anything above 150cc I definitely would want two rings. Single rings have around half the life of a twin ring setup. Also if you have a nikasil plated bore which pretty much any bike 30 years or newer will have, I'd recommend just getting them replated over getting it over bored unless you're looking for power. It's only around 200 bucks to get a replace and it lasts as long as any new cylinders plating will.

[@chasehall1538]

I’m curious as to if the 125 has a bridge port on exhaust side of cylinder, if so you should drill two holes in the piston skirt in the specific location and diameter offered by the company selling the piston

[@jangho9]

Yes this cylinder has a bidge on the exhaust side of the cylinder. Im using cast piston in this bike so no need to drill holes. If i used aluminium pison, i would need to drill holes. See my 2 stroke tech video. All you need to know about drilling holes on pistons is in that video :)

[@Bogdanflorinvitelaru]

Thanks, good job man! may i ask abaut a problem on my husky, i have water in cylinder; after i pulled out it s working good, but at the next igniton it won t start before i pull the water again... what s the problem? I have compression, it s just that my fiche is full of water i guess it s the gasket; Any sugestions?

[@SteveMyBell]

seal around spark plug,casket.....but i suspect the comression and preformance would be down :)

[@Bogdanflorinvitelaru]

you mean the up side casket or on the both up and down (the cilynder) casket? i don t think that it s water under the piston in the engine...(i guess it wouldn t work if it was), also if it runs, i t s ok no mater how i ride it, but on the next ignite it won t work... also i saw that my cooling liquid in the watertank is getting low... so? Thanks again, i ll start the job tomorow!

[@SteveMyBell]

i'm a miracle man i can find faults with out looking or hearing the bike in question....i'm a walking diagnostic prober :)...

[@billtevepaugh]

I just want to know, did you remove the tank and radiator for this? I just couldn't tell in the video.....thanks

[@tylertrexler9579]

I beleive it's time for a fresh rebuild man! to me it sounds like there isn't much compression. Sometimes a bike will just barely idle with low compression, and once you try to give it some throttle it just loses all compression and trys to die on ya. I'm suprised it even starts.

[@enanotech]

1.21 to 1.24, check 19323-KZ4-700 oem part, this bike need it ! Excellent video !!! Greetings

[@nitramh24]

Hei. Har du noen tips for å få pinneboltene ut av sylinderen? Jeg skrur på 2-3 muttere på gjengene, men de sitter bom fast nedi der...

[@ericm1430]

do you not have to file the ring gaps on two strokes or did you just not show that step? I know on my 450 you had to have the proper gaps. Also did you hone the cylinder or is that necessary?

[@suraevlife]

Hello, friend. Please tell me, I have a 1998 Honda cr125r, the crankcase is broken, can I buy from 2001 and rearrange my insides?

[@drumminfreak999]

awesome job!! I just wanted to ask did you test the torque on the screws or did you just tighten them??

[@shaquelledixon6613]

i neeed the answer to this also, very good question!!

[@Michaellpatty]

Awsome! TY for posting this video! well done and the bike looks great.

[@JustinStewart99]

Did your new piston come with a new head to cause the stock piston is dome shaped and it looked like your new one wasnt.

[@cee5902]

What is the piston ring gap for rings on a A cylinder standard bore 2003 cr125

[@kingmatthews5436]

This helped a lot how do you figure out the piston size and do you have to bore out the head if nothing but the rings are bad I got bad rings on a kx125 and it don't go fast at all and I didn't think I had to bore it out

[@Motoxcross]

if the cylinder isn't scored (all scratched up with little groves in it) you don't need to bore it. Vise versa. You need to take it to a mechanic to bore it. I'm sure they will bore it to the next size (example: your piston is 47.50mm they would bore it to a 47.75 or 48.00) Then you would go buy that size piston. (search on a bike store such as motorcyclesuperstor. com, kx 125 48.00mm piston.) Hope this helps a wee bit! :) Good Luck!

[@dustinlambert2030]

Im running short on money, my top end has small engravings on the side. Its a 82 Honda cr125. Should I try to get a new top end?

[@braptasticfilms3791]

when u rebuild a two stroke do u have to hone the cylinder or not...I curious Im new rebuild engines

[@HondaBikes420]

what happened to the rubber seal by the rocker arm that opens the exhaust valve ?

[@TheRossillini]

No measurements on cylinder bore? No squish rate check?

[@Daniel96sj]

Its pretty simple to do, I rebuilt the top end on my YZ85 in 2011 when I was 14 years old by myself... Theres only one tricky part and thats putting the cir-clips in the piston. By the way YZ85 doesnt have powervalves... so im not sure on that, why do you have the dissemble it? I heard its good to do it but forgot why.

[@markking5457]

how come you didnt clean the powervalve assembly and headstuds and the head?

[@MegaJoojee]

it would be nice if you would tell us what year this was made

[@haZy_tree]

How did you get the cir-clips in so easily? I have a 2003 Honda CR125, and i can't get the cir-clip to go on for anything!

[@jangho9]

Thank you so much Aleksas53! I really apprecate your positive comment :)

[@ciprianlodba182]

Hi ,can you tell me how much you have to running-in when tha piston it's new ,how meny tanks of petrol ?

[@jangho9]

I just ride the bike slowly on a gravel road. Let it cool down after then start it up and hammer it. Thats how i do it :)

[@jonlinaresromero6526]

Donde compraste el cilindro piston y junta ? Espero tu repuesta

[@TheFirstMikeJones]

Looking inside my power valve cover, it looks "Clean" inside. Yours looked more "Oily" Should it have more oil deposits in there? I also found two metal pieces in there. Any recommendations on how to confirm the linkage is good and if maybe it is blocked for oil?

[@TheBumcum]

+Michael Jones it shouldnt really be oily, there is lip seals on both the power valve shaft and also on the spline that actuates the power valve

[@martnrs5]

Thanks for the video - quick question have a 99 cr125 power valve is totally different guessing actuator arm is on right hand side of bike 99 power valve looks a bit more complex any advice welcomed - cheers:)

[@johnnymclaneutah]

Nice vid jangho9! did you use torque wrench on cylinder nuts? just asking if its a MUST to use it because my Kawasaki KX 125 has the cylinder nuts in a really tight spot and its impossible to use torque wrench on them unless you buy some specialty tools for it... i'm a bit afraid that cylinder ain't tight enough even thought i tightened the nuts as tight as i could with a small 12mm wrench (that's the only tool that can be used on them).

[@fabianvass5477]

After how many hours you need to change the top end?

[@mondeano2602]

Thank you great vid. Off to install my new piston

[@hcokey99]

Over time and with a lot of practise with rebuilds you get to know the feel of a tourqe spec, but its still wise to check your manual.

[@1slo_cobra505]

Thanks for the vid helped many I'm sure.

[@jangho9]

I hope so too :)

[@hkm_865]

What kind of compression do you want out of a rebuilt cr125. I have 130 lbs in mine. Wondering if this is too low?

[@marklevenhagen3365]

yeah that is pretty low, your cylinder is probably worn past its service limits. mine has 185 without it being rebuilt that I know of...

[@008ozuna4]

que buen vídeo amigo. muy prolijo en tu trabajo. saludos desde Argentina.

[@antoniosolomon8634]

Anybody Know The Piece he's unscrewing at 1:09 please help ?!

[@SuperRandom199]

Antonio Solomon power valve cover

[@gogogadget4842]

Byron Waugh thanks

[@StilwellMotovlogger]

That the power valve cover

[@nickkmaster]

IMPORTANT: does this work for other 125 2strokes too? for example: husqvarna sm 125 ??

[@jangho9]

+Nicki De Luca Yes it will work. All 2 strokes are basically designed the same. But the Husqvarna might have a different design on the exhaust valve. I dont know because i have never had a Husqvarna.

[@nickkmaster]

Ok thanks tho :)

[@terribrain2642]

Is that just standard 2t oil you used?

[@mattletterhouse9414]

what type of grease should go on the roller bearing and the piston

[@captainchaos7706]

Matt Letterhouse just the normal oil you mix with the gas works

[@vkleivane]

Very good video man, thanks you so much! Just changed my first piston, and it work fine! PS: Nice bike you have

[@501stmedia]

This is similar to a 2002 CR80 but bigger cylinder correct? Sorry it's probably a dumb question, but I am just getting into dirt bikes.

[@kooxy73]

I don't know if you still respond one this channel, but at 8:37, do we see the inside of the cylinder ?

[@jangho9]

Yes. What you see here is the exhaust side of the cylinder. The camera if not inside the cylinder.

[@2Fearnone]

How do you know when you need a new piston? I have a 1991 cr 125 that keeps flooding and looks like oil? Is dripping from the exhaust any advise would be greatly appreciated. Thanks

[@reeceduncklee1383]

All 2 strokes should have some splooge coming out the exhaust. Usually on a 125 its like 20-30 hours on a top end. You can open it up and check the walls of the piston to see how it looks.

[@2Fearnone]

Reece Duncklee thanks

[@reeceduncklee1383]

You can always just check your compression.

[@cobra7king]

Hey jangho9 what's the best way to brake it in after I do my rebuild... I have the same bike

[@jangho9]

+cobra7king Hello :-) What i do is to go out for a little longer dirt bike ride. Not on a MX track but on gravel road. Not pushing the engine. Easy riding so the engine gets the right temp. When the engine has cooled down from this ride, i ride her hard the next time :) But thats how i do it. There are many ways. Some are doing very detailed "break in" processes and some ride the bikes HARD the first time after piston change. But i like to be a little gentle to the engine after piston change. Hope it helps.

[@kevinslattery6298]

Cool high level video but I think some people would benefit from seeing some of the low level stuff like how to torque the front cylinder nuts.

[@OGKILLa9365]

please respond.....does it matter what direction you put the piston???

[@Madfishfingerboards]

what the torque specs for the cyl. head brackets?

[@OGKILLa9365]

is this top end rebuild proess the same thing for a 87 cr125r?

[@closeup7861]

seriously cool video and I have exactly the same bike with same graphix except fatty pipe

[@dougmacdonald2870]

How often do you have to to this on a cr 125

[@Headjangle]

Are there valves like on a 4 stroke that you have to adjust? Just a question ;)

[@pronixtheman6934]

When I took off my top end to little black pieces came out and they had a square hole pls help when I pulled off the power valve they came out

[@joshscott1816]

What's that second soundtrack you used?

[@caseyheck4186]

hey i have a question. I don't know if I messed up or not. so my piston is in my cylinder but the head isn't on. I can push the kick start down with one finger. Is that normal because the head isn't on?

[@petroskallenos2573]

yes when you put the head on its going to be right

[@djgproductions8629]

yep that's normal just make sure you seat the head all the way down before putting bolts back on .

[@socks2441]

i admit last time i did a top end that nut under the power valve cover i had to shave a bit of meat off a ring spanner, so i did not properly torque it back down along with the rest, luckily were i work now i have access to torgue wrenches that should allow me to use open end spanner bits to torque it. otherwise a standard socket torque wrench would not fit in there. ( hence previously just doing it up by hand with a modified ring spanner, untorqued.)

[@mattpowell8890]

Most models u just pull out the rods and flap its basically a gate that opens and closes for more exhaust to escape disconnect the one side then pull the pin threw. As in cleaning it i would use contact cleaner or brake cleaner something to remove the oil. Make sure tho after u clean it lube it back up with some rawww premix. Next time if it dirty change your jetting or fuel oil ratio

[@juanrios6820]

Excelente!!! Gracias por subir este video. Super explicativo y didactico.

[@fuckkungenshoror]

BEST VIDEO ON KZbin! i luve u so much ure the most epic dude of all time thank you! :D

[@oliver556677]

u have a very nice bike i just got a 1997 cr125 runs well but doing her up

[@dixiejuggalo]

is this the same as the what u do on a 1990 cr 125r?

[@youthngod]

Thanks much. You made this process easy for me.