2017 KTM 250 EXC Engine Top End Rebuild

[@kevinwren6568]

just something to note, any time you rebuild the top end mention checking the ring end gap

[@TokyoOffroad]

Agreed. I was going to cover measuring ring end gap in the video. There is a section in the KTM service manual which covers the method, but unfortunately no minimum spec is stated in the manual, which makes it difficult to determine if the gap is OK, or not. I decided I'd be opening up a can of worms if I included it in the video so decided to leave it out. But it would have been better if I'd at least mentioned something. My experience with OEM rings in OEM cylinders is they do not require adjustment. But if you're fitting an aftermarket piston kit, or using a replated cylinder measuring the ring gap is very important. Your comment has prompted me to find out what ring end gap KTM recommends. I have asked a friend who works for KTM to find out. When it's clear I'll make an update video to clarify...

[@TokyoOffroad]

I'll make a video about measuring ring end gap and specs very soon. I'm sure it will spark some heated discussion... ;-)

[@TokyoOffroad]

I purchased my KTM Service Manual (DVD) form my local KTM dealer

[@Bradders-ik7bl]

Alright mate.... Over the years I've done a shit load of piston changes and never had one go bad but the ring gap I've never done... Not on purpose I just didn't know lol. Amateurs I know 😂 Is that just luck or does that just show it's not a must ?

[@MtlDeath]

@@TokyoOffroad If the bore was worn, it would certainly affect the compression test, hence you would have seen a problem with the initial test, and if you had used aftermarket parts like you mentioned during the replacement, this may have been necessary, but again your compression test after assembly is adequate assurance, you don 't have an issue.

[@Bikesatsomepoint]

I rebuilt my 2017 250sx using this, just wanted to say thanks for posting such a clear instructional video. Couldn’t find any of those easy circlips in time so had to use the normal supplied ones with the vertex kit and it was the most difficult part.

[@TokyoOffroad]

Pleased to hear that you found the video useful. You should be able to order the easy clips from your local KTM dealer, or online. The KTM part number is 54330074000.

[@BurtoniMotors]

I'm watching you rebuild the top end even though I don't have the bike. Your voice and video is mesmerizing.

[@maxl308]

Berlin Biker Geht mir auch so :)

[@molluscturtle]

Me too - I was actually looking for a video on a four stroke 😂

[@isaacacers3986]

Haha same

[@davidherringgo]

Great job on the the top end . Makes me want to try the valve specs. on my 16 SDR . I'm at about 9 k. now. 18 k. is recommended for checking tolerances .If compression test is fine , can skip the tear down?

[@TheRcscalebuilder]

I cant believe how clean and fresh your bike looks for 145 hours! Great video, very informative!

[@wranglerstar]

Thank you for making this video. I am no longer afraid of doing this job myself.

[@TokyoOffroad]

Overhauling a 2-stroke top end is certainly a lot easier than a 4-stroke. If you have the necessary tools, parts and repair manual there's no reason not to do it yourself...

[@ΧρήστοςΔασκάλου]

Wranglerstar why dont you make videos like that on your chanel to(Im a subscriber)

[@kyplummer3657]

You have a two stroke? Sweet!

[@steelheadstalker4715]

''HEY super glad to see you here, GOD bless you and your family maybe me and my kids will run into you and your son on the trail one day!

[@aarongillespie3352]

Great video!

[@ryanmoore6795]

Killer looking bike for 150 hours, man! staying on top of cleaning definitely pays off

[@mguarin912]

Can't believe he didn't start it for us. 😢

[@Chris-uh3cm]

You provide some of the best instructional videos on the web thank you

[@boblogIIIfan]

This video was playing on my phone while i was in the shed removing the barrell and piston on my 2018 300 for the first time. Thx for the help

[@Riding4Ever]

The video is absolutely fantastic. I have a 2017 Husky TE300 and at 130 hours replaced the piston and rings following your video verbatim. The steps are basically identical on the KTM and Husky 2017 2 strokes from what I can see; You may want to make note of this for all the Husky riders out there. My only regret is not getting the KTM EZ clips as this would have been much easier.

[@Kostas283]

Steve Brown theyre basically the same bikes too,ktm owns husky

[@gupomper]

how thick was base gasket you used? Thanks

[@stughrol]

Hi. I have the same bike (TE 300 17). What size piston did you use?

[@michaelsteven1090]

Dude, you buy the kit for your bike..@@stughrol

[@alinfixo8846]

@@Kostas283 Now it belongs to bmw😉

[@AuMechanic]

I've added a few tips interspersed in comments regarding measuring con rod side deflection and notes on those piston clips. One more tip I would add it always place a rag under the piston as soon as there is enough room before you slide the barrel right of, this saves any carbon or debris above the piston top falling into the crank case and in some cases if you have a cracked ring and you wont know it having a rag there will stop a bit of ring falling down into the casing.

[@Lloydbar]

Fantastic video, not only in terms of the content, but also because of the shooting / editing. It's very rare to see videos of this quality made by people in their own workshop!

[@NTKLife]

Hi, where do you find how much nm you can apply to each bolt?

[@TokyoOffroad]

The operators manual has a tech section at the back with all engine and chassis bolt torques listed

[@pcalvinski]

Am I the only person watching who is constantly amazed by your high-quality tools, tool bench, and the amazing cleanliness of your shop?

[@TokyoOffroad]

I made a series of videos about my shop and tools I use which may be of interest. This is Part 1 of Tokyo Offroad Garage Talk: kzbin.info/www/bejne/hIOvgnqchsp-oLM

[@gordachten9722]

Dude, you work very clean. Thumbs up!

[@ZanoticGames]

Super good full walkthrough, you make it easy to understand by walking it through slowly and you don't skip any steps at all

[@BLDH]

Amazing video dude! Makes me wanna buy a 2stroker. Eaaazy game! ^^)

[@TokyoOffroad]

2-strokes are so much fun to ride off-road. Do it! :-)

[@cadwarrior]

Tokyo Offroad i totally agree!! 2 stroke are awesome to ride!!

[@EarthSurferUSA]

Rode them for all my riding/racing years. I will get another because I love them, and it's my way to middle finger the EPA. :)

[@EarthSurferUSA]

EPA--"Environ"Mental" Protection Agency", here in the USA. Watermelons, green on the outside, red, (commie), on the inside. They deserve the finger. :)

[@tkfore2one918]

"2smoker" and get yourself a 300. we out motor 250f all day long and we can tractor like a boss too

[@_Hangman]

That bike is so clean for that many hours use. You see so many bikes with half even quarter the hours use that are beat to death. Nice job and video too 👍

[@MtlDeath]

Ya take care of ya bike, prolly couldda got another 50 hrs easily before the rebuild, which is remarkable. This video is not only an awesome learning tool if ya wanna rebuild, but also just how long ya can actually run a 2 stroke.. if ya maintain it correctly.. Great job

[@Atacama777]

Excellent tutorial, I really enjoyed viewing it, very professional and clear, thank you for sharing it.

[@JamisonMK3]

Excellent video! Gave me the confidence I needed to tackle this job myself! Thank you!

[@Meadie69]

Had me hooked even though at this point I have no use for this video. Great instruction.

[@mudpro200]

Thanks so much for helping us out with these how to vids. Even I needed a refresher, it's been years since I have done a top end.

[@ProjectCrossEnduro]

Very Good Video 👍

[@sopl1424]

o lol, cxyli nie tylko ja ogladam filmy z naprawy moto ktorych nie posiadam XDDD

[@burntfaceman24]

Great video! You seem to know exactly what you area talking about. You could use crows feet for the front cylinder nuts in order to torque them properly. Crows feet are really great for tight spaces!

[@TokyoOffroad]

Pleased that you enjoyed the video. I made a separate video after this one in which I discuss some solutions for tightening the difficult to access stud nuts which may be of interest: kzbin.info/www/bejne/mH_SemuEmJygoaM

[@jamesbramblett3346]

Excellent video. I don't even have a 2-stroke anymore yet still enjoyed watching your instructions. You are a great teacher thankyee for sharing.

[@MarcosMartinMartin]

Awesome video! Straight to the point and all the information you need to get the job done. Excellent!

[@absolutebullcrap7273]

i must say even though i just watched this for the fun of it you made a very very good video about this man good job i think you will help a lot of people with this

[@darylj2617]

best how to video ive ever seen.

[@jaedenrosner]

fantastic tutorial man! when i go to rebuild my 300xc ill watch this video.

[@michail1963]

Did that a week ago...also disassembled and serviced the powervalve...

[@TokyoOffroad]

Regarding overhauling the powervalve, how much carbon deposit was on yours? When I inspected mine I decide to overhaul it at the next top end overhaul (about 290H) due to minimal deposits).

[@michail1963]

Tokyo Offroad I had quite a lot but I didnt clean it - ran out of cleaner :D...just changed the orings and regreased them

[@TokyoOffroad]

Mikhail - What 2-stroke oil are you using?

[@michail1963]

Belray SI-7 1:55 to 1:60...I like Belray company and their products and I had plenty of SI7 bottles from the times I rode my Beta RR 300 with oil injection...Jeff Slavens advises Amsoil for clean burning but you cant buy those in Czechia.

[@kdcustoms1272]

@@michail1963 on my 04 yz250 the bike ran perfect really, but had a lot of engine noise. i found a worn cylinder and worn clutch.. i thought the power valve was fine but when i removed the main shaft, it came out in 2 parts instead of 1, it split right in the middle of where the middle bolt is on the main shaft. (a new shaft no bigger than a pencil was about $70, WTF???LOL)

[@jakewilliamson7402]

Awesome video mate! Loved the thorough detail, great lighting and camera work 👌

[@TokyoOffroad]

Pleased to hear that you enjoyed watching the video

[@krazed0451]

If you're struggling to get the piston into the cylinder, you can retain the rings with zip ties. It's easy enough to push them off the piston and cut them free once you have enough of the piston seated ;-)

[@TokyoOffroad]

Good tip. I typically can manage OK using my fingers, but I wouldn't call it easy. A small section of plastic pipe with a slit in it and a zip tie round it would work well too I think.

[@kdcustoms1272]

@@TokyoOffroad good tip!

[@HimalayaHoon]

I use a strip of plastic strapping wrapped around piston and pinched closed.

[@Bryankimsey]

YAY..... a nice close up of the X dimension without having to use the special tool AND you gave us some of the range.

[@sucapizda]

I just wish I can afford such supper nice expensive rags one day.

[@beverlyboys73]

I am doing mine in a few weeks. Thank you for the info and video.

[@KevGoesRiding]

you are a great teacher thank you for the video

[@glenmack3640]

Mate that was a really well done video. Good sound, pics etc. I have gone from “hearing” you can do it yourself to seeing “yea I reckon I can too”. Thanks heaps for bothering!

[@TokyoOffroad]

Absolutely. The trickiest part is fitting the cylinder on to the piston and rings. Just take your time and don’t force anything.

[@joewheelie2299]

Nice man. Very thorough!

[@madsen203]

Thank you for posting this. EXCELLENT video! I swear..the oil change on the 07 RFS KTM takes longer than a top end on the 2T. Thank you again for this detailed and clear video. Stellar!

[@jeffreysisti6653]

Excellent video, well explained.

[@amaury1717]

Great explanatory video of the change of piston, I have to congratulate you friend, there are certain aspects that make your special videos such as cleaning, the good approach of the cameras, at every step, excellent tools, you see that you enjoythe mechanics, I follow him in his channel, greetings from Tenerife Canary Islands.

[@massimobroccoli9854]

I do 165 hour (vertex piston) but I change the power valves and the reeds too ! (TM250)

[@TokyoOffroad]

I'm changing the reeds (separate video). Due to the minimal carbon deposits I'll overhaul the power valve when I do the next top end overhaul at about 290H.

[@jackgariepy7223]

Massimo Broccoli I do pistons every 40 hours because at 50 they blow

[@jeremys4705]

Man I wish you would of done this video a month ago. I did my TX300 at 155 hours and wear seemed minimal. It was my first time doing a top end. Easy clips were worth every penny. I thought everything was clean until I used a micro fiber and wd40 and was surprised how much more debris pulled out. Lastly I made the mistake of putting the power valve linkage on before I put the new seal in place. I will not make that mistake again. Hopefully I didn't over torque the power valve covers, it was unclear the spec from my manual. It didn't seem to take as much coolant as expected. Anyway, I tore my UCL in my thumb so I haven't ridden in yet. Fri is test time. I think next time it was go 2 to 3 times faster. I was really cautious the 1st time. I had a little more deposit on power valve so will have to do that next top end, probably around 300 hours or slightly less. Anyway, great video.

[@liamapplegath9134]

Jeremy S 155 hours seams low/early. How long could you push do you think? 200 ? 250? 300 hours maybe on the same top end?

[@lostinpa-dadenduro7555]

Great video.

[@Booki89]

Great video! A good tip to know if your wrist pin clips are in correctly is to use the old piston wrist pin to drive them in. Also don't forget to oil up that cylinder as well !

[@pjbuckmaster]

Another great video!

[@SR3zzY]

Very help and educational video guide Tokyo Offroad 👌👍

[@danielmassee3789]

you actually have a 1/4 torque wrench....

[@rodneykinder9441]

Very good video. Top notch work. I have a 1997 360 exc. Bought new, ran it very much. Never opened it up. Ive also a 1998 360 i recently bought. May redo it first, as its life is unknown. Both run very good, i really want a new 300 injected bike but may freshen up what i have. Probably too old for a new bike. 97 runs great after 20 plus years, and i did run it hard, got it hot etc. Probably had 20 rear tires on it. Ktms are good in my book

[@michaelberry2298]

one time my freind told me to change the power band😂

[@Hoggdoc1946]

You mean the BIG RUBBER BAND inside that makes it all work? LOL

[@MotoPoradniki]

Which color did you go with?

[@self-raisingflour4840]

BMSvideo I found pink give you an extra 50hp

[@isaeproductions5217]

michael berry I mean you can, just add a red or green

[@brianmorrison9066]

Your a pro at getting the piston back into the cylinder while compressing the rings. Last top end on my 250x I had to have my gf handle the cylinder and it still took 10 minutes. Perhaps you edited it, idk.

[@blancolirio]

Brilliant presentation! Subscribed. and let us know when you open up one of the new TPI bikes.

[@TokyoOffroad]

blancolirio - I just purchased a 2019 TPI bike and will be making lots of videos about that. Top end overhaul won’t be for a while though...

[@blancolirio]

Excellent, I just picked one up as well, looking forward to your presentations. I'll do a couple as well and reference your technical vids. as they are so well done.

[@aylha4851]

In Finland we call it "Yläkertaremppa"

[@cadwarrior]

verry verry good video!!! at 14:29, i do the same as you, plus, im using a vacuum cleaner while scraping the gasket residue, works well, no chance of contamination into the base if the engine

[@charles1206]

200+ hours is more than ok on these bikes

[@jarrodjames6896]

How long can one expect to get out of the bottom end, or is it a don't fix it till it breaks thing

[@thomashavas2775]

@@jarrodjames6896 until you here crank bearings or rod has play in it

[@steve5912]

@@jarrodjames6896 Yep until it starts making noises or grinding/knocking. Same with the top end if it hasnt lost power dont rebuild it. Run it very Rich if you want a very long piston/ring lifespan.

[@tonner987]

He he 1st time seeing your face @ 20:00, tnx for all these kind of videos. I don’t really trust people fixing my bike, tnx man!!!

[@TokyoOffroad]

I hope I didn't put you off the channel! LOL.

[@iqmalizzat95]

dude. u can build school of two strokes engine! very educational video!

[@TheMostin920]

Hi, why not use a crows foot adapter on the torque wrench to torque the front cylinder bolts, is guessing the two you can’t see once assembled a good idea? 😁 a good quality reference vid still though for those wanting to tackle the work.

[@extremeenduro1560]

Excellent video, I thoroughly enjoyed watching.

[@LakawanAdventure23]

Thank you so much for sharing this video it helps me a lot as a new motorcycle rider,,from Filipino easy enduro trail riders

[@patgreen6902]

Great video thanks - excellent. All your stuff is top notch

[@andymackay7704]

Excellent... take note people, this is how videos should be done. Superlative!!

[@bast2957]

Thanks you a lot; it's time to replace my piston off my 250 TEi; it's a little bit different but your instructions help me so much.

[@TokyoOffroad]

How many hours had you done and how did the piston, rings and cylinder look? I have just bought a 2019 KTM 250 EXC TPI so I'm interested to know whether the top end will wear as well as my 2017 KTM 250 EXC (carburetor model)...

[@bast2957]

The bike have 76 hours; i can hear small noises during deceleration so i prefer changes it. But my bike got some problems with the injection at the start and suffered lot of tests for the diagnosis. I will changes it when i received the new piston (this week i think); if you want i can send you some pictures of the different parts when that is done. Sorry for my bad english ;)

[@TokyoOffroad]

The 2019 map for the TPI is meant to improve starting. Maybe discuss with your dealer if they can update the map...

[@bast2957]

I mean "at the start" when i just buy it; at 20/25 hours; when i accelerate quickly the bike suffocating like a bad carburetor adjustement; the customer service never found what is the problem; they just change entirely the system of injection. A real nightmare during 2/3 months!

[@jacobvogt8996]

Is that a 4 stroke or 2?

[@mbrick]

It would be a little more helpful if you provided the torque values either in the video or in the description each time you used the torque wrench. I heard a few but not all of them. Very nice walkthrough giving a lot of attention to detail. Great editing, narration and video quality.

[@joski9030]

I always remove the motor so can clean it up like new as with the frame , but you obviously know what your doing here and this way is much quicker nice vid 👍🏻

[@daibennett9224]

Good video,time to say goodbye to my wr450f soon,just had a engine rebuild done on that,cost me a few bob,I didn’t feel confident to do it my self,but two strokes are just so much easier to work on,with a lot more room to do so,150 hours is good,i think it had another 50 left in it

[@TokyoOffroad]

I'm up to 437H now and fast approaching the 3rd piston change at 450H. Considering the ease of doing a 2-stroke top end overhaul and expense (quite reasonable) I don't think it's worth pushing the piston life to see how long they will last...

[@williamstones1773]

Nice video, well spoken and just the right amount of info. Love your work.

[@jamielee2702]

Going to do mine this sunday 😁👍🏻

[@aimlessimages831]

Excellent step by step!

[@robertfeddeler5508]

One suggestion is to use a heat gun or hair drier to heat the piston up. The piston pin will just push out but of course you'll need to use gloves.

[@EarthSurferUSA]

One important part you did not mention, but did, is not to twist the cylinder when putting it over the new piston and ring(s). You want to orient the cylinder as straight as you can before you slide it down, because if the ring end grabs a port, you can damage the ring very easily, losing compression and possibly damaging the cylinder also. You should not worry about the deck height. The manufacture has the tolerance stack up all figured out to assemble the parts to get the clearance you need, (which is bigger than optimum for mass assembly because of part tolerances). If by a very slim chance you find you don't have the clearance you need, (one out a million if at all), you either need different thickness cylinder base gaskets, (which are probably not available) or a machine shop to fix the problem. Trust me--the manufacture has the tolerances figured out to just be able to drop in the OEM parts, or else they would have serious problems with the assembly at the factory. I build 2-stroke engines for a living, (smaller--much), and have a manufacturing and a quality engineering degree. The manufacturing engineers engineer the squish clearance to be big because the 5 parts involved have a dimension tolerance. But if you can find thinner gasket to use, (or a machine shop to cut the base of the cylinder), you can optimize the squish clearance by lowing the cylinder, and gain some mid range punch. The deck height is just part of the squish clearance, and it is the squish clearance you should be measuring if you are optimizing the clearance, or worried about the factory parts not fitting right.

[@TokyoOffroad]

EarthSurferUSA - That’s good advice regarding not rotating the cylinder while fitting the piston. Not sure why you said I rotated the cylinder though. I was careful not to. Regarding deck height, the KTM piston kit comes with various thickness gaskets. You need to figure out which thickness to use. As I mentioned in the video, if you’re using the same cylinder you can use the same thickness gasket which was previously fitted. If however you’re using a different cylinder it’s a good idea to check. It only takes a couple of minutes...

[@Jrod_FPV]

At 11 minutes, When trying to prevent hammering forces from going past what you're hammering, place another hammer in contact with the backside of your target. In this case the piston. Use a similar weight or heavier hammer or any solid metal object will work. This will also work faster than trying to hold something in place by hand.

[@Micscience]

I used to put all my nuts and bolts into trays when I first started wrenching through experience I have learned to put them back in place where they belong. This way you know exactly where it goes and you don't lose them and if you forget something the nut or bolt will give you the clue. Anyways nice job and nice bike.

[@malibu188]

Covering the crank case opening before removing the circlip in the piston (and installing the new clips) is a must do. Guess who dropped one into the cases one day - it's a big hassle to retrieve it.

[@TokyoOffroad]

How did you manage to recover the circlip? A magnet on a telescopic rod (which I have just in case...)?

[@coloradocrawler2010]

If you lightly oil your base gaskets they won’t stick when you remove the cylinder next time around (no scraping required). Cheers!

[@scottswastesystemsllc9798]

Great video on rebuild. Well done chap!

[@joby602]

What's with all the downvotes on this video? Amazingly clear and easy to follow!

[@dannelson3432]

I was thinking the same thing. How do you dislike this video??? Great video. I do my own work but wanted to see someone do a topend on a TPI bike because I just got one.

[@tjlovesrachel]

jb602 haters that have playschool tools and rather pay dealer charges

[@TheRhodes76]

Great video, thanks for sharing! I'm more confident doing my own when I finally find one 🙌

[@saavi4739]

Its good idea to add some oil to the cylinder ass well makes it a bit easier to install and you can be sure that it has lubrication when you are starting the bike

[@kons6]

thanks a lot, have just completed my first piston replacement according to the video had 2 issues: one of front cylinder nuts tightened not enough and outer head o-ring misplaced and smashed by the head; both of them solved

[@TokyoOffroad]

I made a follow-up video regarding torquing the stud nuts here: kzbin.info/www/bejne/mH_SemuEmJygoaM The 13mm torque extension shown in the video is available for sale on the Tokyo Offroad webshop: www.tokyooffroad.com/product/signet-30493-torque-extension-13mm/

[@kons6]

@@TokyoOffroad thanks once again; for this piston replacement I tightened the nut at the leaking corner and changed the smashed head o-ring. it helped: the engine is dry again.I believe 6 hours is a good proof of the successful work

[@TokyoOffroad]

@@kons6 - That's good news!

[@Billyjackkson]

i trust this guy with my bike anyway 😂👍🏼great video

[@justinmoto929]

On my 2016 KTM 250sx the compression test before my rebuild was around 140 psi... definitely time for a rebuild haha

[@DavidJohnson-rd5wy]

you must have done this out of sheer bordem, with that compression reading, I would have spent that rainy day drinking beer and watching ball games... this bike is so mint that I'll bet you ride it like the book tells you also.......

[@TokyoOffroad]

No, I change the piston every 150H hours because that's what I've determined to be a reasonable interval. The manual states every 80H, but I derate that because I don't ride the bike hard. The issue with waiting too long is that the chance of catastrophic piston skirt failure increases significantly. I wouldn't recommend going beyond 200H and if you leave it until 400H I'd say there is a high chance of failure. Piston kits for these bikes are relatively cheap and easy to install as shown in the video. For the riding I do it means changing the piston about once a year. I'm up to 410H hours now and ride in all conditions. I'm not sure which book you're referring to regarding how to ride the bike. I tend to watch more videos than read books nowadays. This is the ride last Sunday in slick muddy conditions: kzbin.info/www/bejne/iZ3Hk32we8t8d6M

[@reignhealth]

Very nicely done, great video!

[@jaredbuchholz2010]

Nice video! Only problem I have is how you torqued the cylinder down? Box end wrench is not a torque wrench. But to each his own.

[@TokyoOffroad]

Pleased that you enjoyed the video. At the time of the video I didn’t have a method to torque the two forward cylinder stud nuts. However, I do now and made this update video which you might be interested in: kzbin.info/www/bejne/mH_SemuEmJygoaM

[@slickricktheruler]

Outstanding video buddy! Thank you

[@TokyoOffroad]

Glad you liked it!

[@79brumley]

Rub silicone grease on the gaskets and it makes the gaskets come off in 1 piece and they do not stick at all!

[@Tensioner]

If you wanted to get tricky, you might be able to put an indicator on the cylinder studs and match the stretch. Don't know how it would work on such short studs but it might be fun to see what happens when you loosen them. -It's how some guys do car heads. Nice vid.

[@TokyoOffroad]

Yes, that's certainly one method you could use. I did it by feel in the video and it was easy as I was able to use a torque wrench on the rear feel (and remember how that felt). But I've since purchased a 13mm torque adapter so next time I overhaul the top end will be able to use the torque wrench on the front studs too.

[@franceadventure8080]

Two stroke seems like a lot more easier. How about 4 stroke? Can i request? I learned a lot thankyou 👏💪

[@raymann4232]

Great video! I love watching rebuild videos. Subscibed!

[@TokyoOffroad]

Brandon - Thanks for the positive feedback regarding the video and subscription.

[@sam-ww1wk]

You make great videos. Keep up the nice work.

[@TheBabyOstritchesCold]

The EXC model is built for the road there’s no need to ever pull one apart till it is needed or bike is starting to lack in anything such as power,compression or just lacking in general this bike in particular will outlast over motocross bikes it’s unnecessary to pull them apart well atleast I wouldn’t as long as it’s been looked after and you look after it, air filter spark plugs, fresh fuel the piston and rings should last a life time as you said in the video there was 150 hours on the bike with no visual major damage at all, i have the 2003 model of the 250 exc 2 stroke got it brand new from my local Ktm dealer, I’ve never done a rebuild on it only services and aftermarket parts and other then that the only thing that’s gone wrong with the bike was water pump seal and radiator cap seal and also other then that just tlc things like chains and wheel bearings, fork seals but they’re common unlike pulling an engine apart and doing an overhaul

[@EarthSurferUSA]

One thing that I did not see, is if he used any oil for the cylinder. Back in the day, pro mechanics would put a top end together dry at the track, (if needed), to help speed in the ring break in process during practice before the race. You can use a bit of your 2-stroke oil, but I used a happy medium with wd-40. One other thing you should do is clean up the plating a bit with scotch bright or 1000 grit sand paper, (wash cylinder well after that), to remove the old tarnish to help the new rings seat fully quicker to prevent blow-by as much as you can.

[@tyroniousyrownshoolacez2347]

You helped me alot. Thanks for sharing. 👊

[@MurderVetteZ]

If you throw in a piston every 150 hours or so, it’ll wear out the cylinder bore a lot faster, just replace the rings if that’s even need and the wrist pin bearing if needed. I have a little over 500 hours on my WR305 2 stroke now and it’s still running like brand new. Cylinder and piston look brand new and the rings had minimal wear on it. Keep in mind I race hardcore enduro and fast pace hare scrambles.

[@TokyoOffroad]

I base the topend overhaul period on compression testing, visual inspection of the piston and cylinder, ring end gap measurement and cylinder bore measurement. This video shows the bore measurement of my cylinder after 295H and a brand new cylinder: kzbin.info/www/bejne/jJ-5oKaJqquMY6c This video shows an inspection of the topend after 295H (150H on the second piston): kzbin.info/www/bejne/bpmpooqNis1krqs For the riding I do on this specific bike (2017 KTM 250 EXC carb model) 150H intervals are proving to be no problem at all and I'm not seeing the high wear levels that you mention. In sharp contrast, a rode a series of Honda CR250 mx bikes in the 90s/early 2000s and would overhaul the top end after 40H on those. I certainly agree that replacing the piston and rings sooner than later is better, but in my experience the topends last very well on late carb model KTM 250/300s. I mentioned it in the inspection video, but I think some factors other than engine design and material choice also play into the longevity of the piston, rings and cylinder, including 2-stroke oil (and ratio), keeping the air filter clean and oiled correctly and cold start startup procedure. If you like to rev the hell out of your engine to clean it out just after you start it, IMO it's about the worst thing you can do for engine wear. The piston heats up faster than the cylinder, so if you want to minimize wear it's important to let the engine warmup slowly and not stress it until it has reached operating temperature. If I was racing I was certainly perform topend overhauls more frequently, but for my use (on this specific motorcycle) 150H works well for me.

[@woodworm3615]

Great video. Very good to refer to when its time

[@mattiasmyrman]

Love this video! Thanks!

[@mackluvall6592]

Good rule to go by anytime working on the top side raise the compression in the cylinder

[@hectormiguelluzongiron7424]

Very good explained. Good job. Congratulations.

[@UnDoDGeAbLe]

What an excellent video, very very well done!!!