KX 250 Engine Teardown Build Part 1

Today, we split the cases, and get ready for a complete rebuild on our 1999 Kx 250 motor. At the time the 250cc had peak power of 42.5 horspower. But that is with factory jetting. We talk about going to a 295cc big bore kit and adding some power mods that should boost us to around 60hp at the wheel. Stay tuned!
Part 1
Thank you to gopwersports.com
🔴Thanks for watching!!🔴
😁 SUBSCRIBE for more awesome content! 🡆goo.gl/APMj6G
Don't forget to smash that like button and hit that bell 🔔
🡆Follow me on Instagram @vasily1fab
/ vasily1fab
🡆2nd channel: goo.gl/VefhDW
🡆Donation Link: goo.gl/ZxbUeG
🡆Support me on PATREON: / vasilycustombuilds
🡆For all serious inquires email me [e-mail]
-----------------------------------------------------------------
🎵 Music used in video:
(support your artists)
•1st song: Roman Sky - Everybody [Free Future Bass] NCT Release
•2nd song: Ed Wilton - Summer [Free Deep House] NCT2 Release
•3rd song: RAIN & Dieom - BEYOND [Free Trap]
•Outro: Heuse - Stones (feat. Chris Linton & Emma Sameth) NCS Release
Family friendly

[@McStovepipe]

Awesome build. Thing is gonna be amazing and turn a lot of heads. I raced growing up and still into moto. Tried to keep most of my stuff stock, but I'll list what parts I'd do. Pipe - Pro Circuit. Piston/Crack - I agree OEM. I'm not a huge fan of big bores. Clutch plates/basket/cover - OEM or Hinson. Boyesen has some sweet covers Gaskets - OEM or Wiseco. Reeds - VForce. Bearings - Pivot Works never failed me. Oil - Maxima Hour meter would be nice to keep an eye on oil changes. Works Connection makes a good one along with other sweet little things like oil caps and radiator hoses if ya want to dress it up. Highly recommend rigged up a steering damper. You're gonna be going FAST. Just a few things that stuck out to me. Enjoy the build!

[@VasilyBuilds]

Thank you for that info! I will look into it Hour meter and tach is definitely a must

[@MrJeffharper47]

Can believe that crank just pulled out so easy by hand like that. Insane. No wonder it was smoking bad

[@kylebarns7129]

I like how your going with a full quality rebuild on this engine. As far as big bore, that's up to you. You can always keep it stock an rock that for a bit. Or go all out n create a monster. Those are good engines to keep around for future off road creations. Keep up the great video's.

[@VasilyBuilds]

thank you. still unsure about big bore

[@hugieflhr03]

I see you s-end a lot of time cleaning, for which is great but next time, just pick up some eagle 1 cast aluminum mag cleaner. Just spray it on and wash off in a few minutes.

[@paulmoysa1787]

Your videos inspire me to get off the couch and go finish my projects

[@benspeedschannel888]

I’d leave it as a 250, the kx250s from that era were powerful and aggressive right out of the box. I would be more than happy to re use the wiseco crank, their products are excellent quality in my experience 👍👍

[@exoticcreature3059]

@@DieselRamcharger Cryogenic freezing treatment for the crankshaft is an option.

[@JohnWheels]

Great work! I love those intro edits!

[@peterw8690]

You remind me when I use to do things like that God I do miss it keep it up buddy.

[@overdrivegokarts6849]

O snap do the big bore kit You are going to have some crazy power to those tires

[@blainewigley4622]

I use a dremel with wire wheel/scotch bight to get into all of the tight areas. Works really well for me!

[@vhjvbhjb5280]

If you are going to drag race, a temp gauge is a very good thing to have, to make sure that it doesnt sieze. And to make sure it is all warmed up before doing a pull. The scratches in the cylinder could have been Cause by the shavings in the oil, but they look like schratches from revving from when cold. The crank seems to be fine if you want to be 100% sure it doesnt have any play use break cleaner to clean the bearing and the you put it on a table and check. To increase reliability you could check the balance factor and make sure it is balanced correctly yours should be about 40-45%. Getting it professionaly Tuned to make sure it isnt lean. You could Also adjust timing to increase power. And getting the correct stinger ID Will increase bottom top and mid range power

[@johndudleyarmstrong5318]

We love the Chanel and content cos of you so do your thing & we will follow 👌🏻👍✌️

[@VasilyBuilds]

Appreciate it man!

[@johndudleyarmstrong5318]

Forgot to say as well to help you in advertising and getting sponsors. You mentioned a big bore kit and who does it, what it’s called etc. If they don’t sponsor you they have free advertising now on this video so take care for future videos ✊

[@VasilyBuilds]

Yeah good point. I can edit it out on youtube if it doesn't work out

[@johndudleyarmstrong5318]

Hope it does mate, ✌️✊

[@KingCast65]

I like your tone and stuff. Good Times!

[@bwxmoto]

I like your "Hello Kitty" radio.. XD

[@jape530]

You can save money by fixing old cluch basket. You can smooth the paddles from basket by using file. It's not perfect method and basket will worn faster after that, but least clutch workin ok. I'm having filed basket in my sx 125 and drived about 30h after filing with no problem. You can chance new basket later if needed. Keep on good doing!

[@kylelangworthy9641]

Man that's awesome I just bought a 98 KX250 2 months ago the motor blew after one ride then I had to spend another 900 on eBay for a engine it ran fine but the transmission is locked up completely out of money now and have a baby on the way Thursday would love to be able to do what you did with my engine

[@Patricks_Projects]

I´ve gone the other way,, de-stroked it to 211cc and ported it heavily, best dyno so far is 69.79hp to the wheel at 13200rpm, old vid of earlier dynopulls at my channel.

[@VasilyBuilds]

That's amazing man, will the internals handle that? Is there a forum or a website about this

[@Patricks_Projects]

@@VasilyBuilds There´s a custom crank in it with a lightened maico 490 rod. Transmission has no problems as it is less torque with peakpower higher in the rpms. Only issue i´ve got is balanceproblem as it is quite heavy things rotating inside the engine. But i have added a balanceshaft that should help the issue. But it is not started yet. I also run KTM SX250 piston, Forged Woessner with only one ring. I run the engine on methanol to help get some power and not overheating it. It is built to run on 1/8mile dragracing

[@Patricks_Projects]

No forum or website, sorry.

[@chaddleix188]

Very impressive Vasily. It's great to see a younger generation not sitting on their asses playing video games, but rather actually doing something constructive with their time. Your an intelligent young man and from what I just watched, your gonna be successful, that is if your not already. Keep up the good work, and if it helps you out I'll subscribe to your channel. Thanks by the way, it leads me to believe there is still hope for the younger crowd ✌️

[@chaddleix188]

I know I messed up. I just realized I posted this in the wrong spot. I was curious about the gentleman above talking about destroking his motor and wrote it in the wrong location. It's hell getting old my friend🤦‍♂️

[@slow4.o]

Great video man!!!!!!

[@jaredromero9549]

For the clutch basket just Dremel the notches out. I race motocross and have been doing it for year. You can do it about three times per basket

[@VasilyBuilds]

I ordered a billet one because I feel like the previous owner had already filed it down

[@dr.hugog.hackenbush9443]

The top of your piston and cylinder head shows an ideal pattern for deposits- your jetting was absolutely perfect! While its a little on the pricey side, a Hinson steel clutch basket will last the lifetime of that engine.

[@alltheboost5363]

FYI you can use a Dremel... they make the same little wheels that you were using and you can get in all those little tight spots.

[@jonnyc2.047]

THE CRANK IS YYYY THAT BIKE IS BROKIN

[@TheBobinn]

Epic video man! Something my stepfather taught me though was to always put a rag around the shaft when you remove the cylinder and then the piston so you wont drop any rings into the bottom end, had a piston ring break once and it was so close to fall down, would have required bottom end rebuild aswell :D

[@propabilityfpv303]

Man if I wasnt eating taco Bell for breakfast lunch and dinner I would definitely support you in patron 😂

[@mbrrideitlikeyoustoleit8436]

Taco bell shit I'm eating Ramon... Taco Bell is not cheap my friend.

[@propabilityfpv303]

@@mbrrideitlikeyoustoleit8436 try the new dollar menu? I can survive off of $3.30 with 3 cheesy rice and beans barritos a day with a water cup lol

[@VasilyBuilds]

I can beat you. I ate 2 McChickens and a water cup for 2.18 when I was in school

[@propabilityfpv303]

@@VasilyBuilds lmao

[@agpjgpoiawe]

YEEEEEEESSSSSSS!!!!!!!!!!!!!!!!!!!! literally just freaking commented on the original purchase video that you should do this big bore lol you already did it months ago. SOOO sick dude, still let me know if you have any questions or ideas for the bike and need advice ive built a handful of kx's from 99-02

[@agpjgpoiawe]

Oh and if the torque makes your nuts suck up into your stomach drop a fly wheel weight in on the bad boy and it will smooth out the powerband so you can hold on to it better

[@Smokkinboots919]

Love the vid, I’m currently stripping down my 03 kx 250. I was thinking powder coating my cases but the clean oem looks is amazing.

[@aliciaantoniadis9100]

Thank you very much for this. Very clear and educational. I am looking forward to the next part. Be well.

[@VasilyBuilds]

Thank you

[@bama6115]

Awsome job Bubba! ~Roll Tide~

[@luismelendez935]

Great video man,very helpful and step by step!keep it up.where did you bought the bearings

[@GCorona32]

I can Vapor Blast those cases and the rest of the engine outer components for you with excellent results.

[@codybuxton]

Yeah buddy!

[@coreymarshall4879]

I do like ur top secret engine room. That stereo is on point

[@VasilyBuilds]

haha thank you

[@bentvalvesnthrownrods3057]

O yea that’s nice good job. Take care of her and she will take care of you

[@driveitbreakitfixit7496]

Hey man this thing is sweet!

[@laverncarroll]

Really enjoy your videos

[@VasilyBuilds]

Thank you!

[@RIPPERTON]

7m 25s the breather respirator for the aluminium dust is a good idea. Im 53 and recently had a heavy metal spectrum analysis done on my hair and it showed Aluminium, Lead, Cadmium, Mercury and Arsenic on my brain and circulatory system. So yes aluminium can be respirated into your body. This contamination is being treated with Zeolite and the effects are noticeable.

[@VasilyBuilds]

Thank you for keeping me aware get well!

[@StilwellMotovlogger]

If the grooves aren’t terrible on the basket you can file them down and save some money. Did that with my kdx and no more stalling when you put it in gear, a lot smoother

[@timl7947]

Jeez man your videos are top notch quality

[@btaylor9748]

You did a great job with this rebuild man

[@VasilyBuilds]

Thanks!

[@btaylor9748]

Vasily Custom Builds you betcha man!!

[@ryandrant2927]

Cant wait for the next episode I think I'm addicted subbed and liked👌👌

[@VasilyBuilds]

Thank you!

[@robspear03]

VERY excited for this kiddo. Im making it a point to watch this build series whenever it comes up. Perks of being self employed...boss cant get mad at me for slacking off!!!

[@VasilyBuilds]

Haha thank you from for the support

[@robspear03]

@@VasilyBuilds Very welcome. Keep it up!

[@500yardsplus]

Just file and polish the fingers on the clutch basket and it will be just fine.

[@mxrider2strokebraaap54]

Man you’re going all out with this kart build!🔥

[@VasilyBuilds]

yessir

[@davinlyda1461]

That crank looks fine. I have ran wiseco cranks in a lot of bikes and they all have been fine. The big bore will wear the bottom end faster but the power would be sick.

[@Darthvolvo]

This looks like it's gonna be a fun project to follow!

[@PaPWPW]

YES to the big bore kit

[@pimvandecoolwijk8977]

Use some kind of lubricant when splitting cases just use some wd40 between the case gaps

[@brianjacobsen5762]

You get 55 that's pretty good. My 88 kx 500 motor is 55 hp stock. Have friend that races off set dirt kart. 450 4 stroke or 250 2 stroke. He runs Honda 250 no trans. Makes 80 hp. There real competitive. His son won championship for that class he races in 4 stroke class I forget what they call it. Have fun don't get in trouble.

[@VasilyBuilds]

Awesome! How would you delete the trans!? Is there a kit?

[@jacobanthonyestrada6514]

Can’t wait my boy!! Good stuff!!

[@pik2490]

The big bore will give you more low end grunt, less top end power essentially dropping your power band to the bottom of the rev range... Which if you're looking to drag race... its the exactly the opposite of what you want. Take the stock cylinder somewhere to get port and polished by someone who knows what they are doing. Aslo a "dingleball" honing brush is a bad idea on a 2T because it will beat the shit out of your intake and exhaust ports.

[@linkerp]

Send the cases for vapor blasting. Check it out. Sweet shit!

[@VasilyBuilds]

I got some pads coming in. How cheap would they do it for?

[@linkerp]

Vasily Custom Builds not sure but we have a guy in South Carolina that would do it pretty cheap since you have it torn down. Makes it look brand new! Privateerconnection.com

[@joshtheincrediblechicken5423]

If you want a good clutch for the money get the tusk heavy duty it’s $50-$60 for the fibers,steels heavy springs and gasket and they hold up really good in my experience

[@VasilyBuilds]

Thank you for letting me know will look into that

[@luckyduck3594]

Congrats on 21k!!

[@kita17n]

COOL BUILD, NICE WORK MEN - MY 87'HONDA CR 500 WAS 61 HP STOCK

[@orvillenorth8815]

Boyesen reeds are supposed to be a great power adder on those 250’s. Never really had experience with them personally but have had plenty of friends install them on their bikes. Power reed a jet and full pipe is all a 2 stroke should need. Especially on top of a fresh oem full rebuild should be a strong engine.

[@VasilyBuilds]

Got some on the way 😁 thank you for the feedback

[@orvillenorth8815]

Do you have any type of formal schooling? Personally I don’t but I believe I’m a decent mechanic. I’ve just learned from repair manuals and KZbin. You’ve convinced me you know what you’re talking about. Which is why I keep coming back to your videos every time I see a new one. Regardless though you’re doing great and I support what you’re doing.

[@VasilyBuilds]

Thank you sir. I don't have any special schooling. Just a diploma. I watch allot of KZbin videos and educate myself before doing anything. KZbin is the best way for me to learn because it's visual. I also look at alot of forums and comments. Like when I bought my first dirt bike I had no idea what was wrong with it and now I know.

[@VasilyBuilds]

Im sure Boyesen has Dyno graphs for that . Stock reeds can be a tad restrictive. With boyesen, you usually have to go down on a main jet.

[@lomsomesGarage]

This is going to be a epic build keep the viedos come

[@JesseFloris]

good on you mate

[@lof7845]

What size aluminum tubing do you use for a go kart frame? Also how much does this engine cost and where do you recommend getting them?

[@ComputerCapone]

Vapor blast next time. Looks OEM fresh.

[@kaarlisandersons]

i will wait the next part, amazing project dude

[@bikestrikes4557]

Wow man for your age and everything you are the man awesome job I'm fixing to do my Kawasaki Ninja the same way I'm fixing to try to put it on a ATV instead of a go kart but I hope mine turns out as great as yours does man keep up the great work God bless and keep them coming

[@VasilyBuilds]

Thank you God bless

[@flynnnewton3324]

This go kart is going to go fast as

[@awdrifter3394]

Wow, 60hp out of a 250cc, it's crazy how much they can get out of these engines without all the emission bs.

[@robertoultreras2773]

Que torque se le da a los tornillos de la cabeza y de la tapa ?

[@bjm1682]

It's going to be crazy fast! Would be crazy fast stock but the more power the better 😉

[@rspeed5008]

Gonna be guud when this baby runs!

[@tajjson]

Nice build, do you have a link for the ebay scotchbrite wheels?

[@madpups9849]

Eric sponsor the man

[@VasilyBuilds]

I wish

[@Matthew-wj8cm]

Great job Vasily! JUST waiting fór the 2 stroke scooter.

[@VasilyBuilds]

Thank you! sorry a little delay on that becuase of this

[@robertscartbuilds9833]

this is going to be crazy fast

[@Giant2020creepin]

Brillo pad for hard to reach areas.

[@nate.1623]

hey I'm not sure where you're located or your time table but you should consider contacting crank works they have microbalance cranks and you can really feel it in the fact that there is very little vibration. id say its definitely worth it

[@d.c7464]

K&N air filter cleaner is amazing on aluminum.

[@andrewsmith-zi7db]

Hi really like the videos great content great to watch really interesting to see it come together keep them coming

[@therocky1157]

Love your content man!

[@VasilyBuilds]

Thank you!

[@motoboystv3338]

Awesome start man i'll be doing a build just like this!

[@VasilyBuilds]

[@hegelhegel4191]

KIPS 💥

[@chrisstenzel454]

Please keep it stock bore. At least till everything is buttoned up. But it’s up to you

[@VasilyBuilds]

Yes I do want to get it running first. And ill see if that's enough power for me

[@owenbatchen8927]

Use MAG wheel cleaner it cleans aluminum very well

[@TheDarkllord666]

Get an Rk Tek head. Raise your compression but you'll have to run race gas or e85 and get a good reed cage and lectron carburetor

[@madsringgren3358]

Nice video!

[@Blessedlungs]

Boysen rad valve for the reeds and do a phathead racing head and big bore

[@kawicepticon8866]

get some port and timing work done to get max over rev capability on this puppy

[@carsonsmith3959]

👍Gonna be a great Build!!

[@AndrewBurtonS-group]

what wheel are you using on the hand grinder on your parts?

[@GoKartsorGoneFishin]

Like #175!..keep doing what your doin!

[@VasilyBuilds]

thanks brother

[@abde4645]

👍💖💖💖💖💖💖 keep up

[@jasonreyes6830]

Can you build my kx250? I’ve got everything just need a new crank case

[@blaketweedie3624]

Keep the wiseco crank and buy the rebuild kit for it, better thank a oem crank

[@Realryancurry]

You’re over your head! It is not a few hp. I’m being serious, not hating. My suggestion on this build would be get the missing bolts, use gaskets, have the crank trued, replace bearings, seals, clutch basket, piston kit and wrist pin bearing, hone cylinder. Your frame needs more clearance underneath it, and you need to run and repack the silencer! If you want power characteristics to change have EGR change the porting. Good luck, hope you’re reading comments!

[@VasilyBuilds]

thank you ill check all that out. I wont run the big bore for know

[@aatos8522]

Notification squad!

[@JesseFloris]

I really want a moto but no money at the moment

[@margieward8153]

Nice engine by the way I suggest you should make a amphibious vehicle it'd be really cool lol

[@Mish93Will]

You need to try do an electric start setup on it. TAG karts are the way.

[@markkus1134]

The crank and transmission are sealed from each other some metal from your clutch would not enter your bottom end . You probably have bad crank seal..

[@ratedredneck96]

42hp seems a bit low for a 250 2 smoker, i read that 90's kawasaki 125cc 2 smokes made around 35 or 40hp. The 250's should be making at least 45hp or around 50 stock. My kdx200 makes 30hp stock, i put vforce3 reeds, a pro circuit platinum pipe with a fmf powercore2 silencer, and a wiseco offroad performance piston in and or on the engine. I removed the intake box snorkel to allow the reeds to pull more air easier and release some good ol power lol id say its running around 40hp when its leaned out a bit.

[@VasilyBuilds]

I guess Ill have to dyno it and see. I really can't pull any numbers out my head because when I was riding it it was sucking tranny oil and felt like 30 hp. 250 is a torque motor I guess, 125 n 85's rev out higher and hit harder from what I've heard

[@Heddan1992]

You actually think you got 10hp by replacing some basic stuff like that? Well no

[@ratedredneck96]

@@Heddan1992 what do you mean basic?!? Two strokes dont take much to run. If you can allow them to breathe better and exhale better you can free up a lot of horsepower. Stock kdx's make around 30ish hp but they are jetted real fat from factory, a full exhaust system really adds a lot more power than youd think, it can then actually burn all the fuel well that the stock jetting dumps into it. When you get high performance reeds, an E3 plug which was proven to burn better and increase power, put a lighter piston in it, and put a full exhaust on it theres not much that wasnt touched on a 2 stroke. Now a 4 stroke you have valves, valve springs, cams, all kinds of stuff that has to be changed to see a power difference. With a 2 stroke you can add several horsepower just be leaning it out and letting it rev out higher, you chance scorching the rings or burning a hole through your piston but you can make a 2 stroke blow itself apart easily from too much power.

[@roberthellmich27]

Youre not getting 10hp from reeds and a pipe, u would need compression and porting

[@ratedredneck96]

@@roberthellmich27 its got an aftermarket wiseco piston thats hemispherical, i dont know if the stock piston was a flat top or not but if it was than it has a hemi piston in it now. As far as the porting, the sleeve does look like its been gone through a little, its not major but the ports have been beveled a little bit. I have a dremel with an extension piece that allows fine milling in tight spots. Id like to learn the process and do porting and polishing myself, i know not to polish the intake because that slight turbulance helps break up the fuel and vaporize it better but as far as anything real technical i dont know. With older bikes thats passed down from person to person its untelling what has been put on or in the bike, as far as i know the head is stock but it may be shaved. I have only ever looked at my kdx and dont have a compression tester to see where its at. I would like too down the line get a new jug and sleeve and port it and maybe shave the head down a tiny bit to make it more of a thumper. Its got a mean powerband hit though, the vforce3 reeds helped out a lot and i know for a fact it picked up some hp gain.

[@lucasrosas5594]

Hey man I have 2000 Kx250 and I’m trying to figure out how to remove the clutch actuator. Any help is greatly appreciated!

[@yarikstuntrider]

Good)

[@darringoodbrand6603]

Big difference

[@jefftheis742]

Wow ,some folks need to ease up on the name calling,yes he is not a professional engine builder but he dug in and is learning by doing it,I'm doing a 94 kx 250 big bore and will be following your project.good luck...cheers

[@VasilyBuilds]

Thank you sir! I cant wait to assemble it , keep me posted on the EG kit I am curious to see how it does

[@jefftheis742]

Check out Shane Connelly videos he's got some very helpful videos on working on these motors