How-To: KX250F / RMZ 250 Top & Bottom Engine Rebuild - Part 1 of 3

[@HTMR]

Full video -> gum.co/dvEoC

[@Tizzy_p]

Yooo bro

[@riennafoutre3833]

you make me start to like 4-strokes mate ! i've always been a 2-stroke guy but i sold my cr125 just yesterday and im buyin a rmz450 2008 tomorow that needs a rebuild , im so looking forward to it ! of course 2-strokes are way easier to rebuild but we're in 2016 now and i think it's time for me to step into 4-strokes ! great video ! thanks !

[@HTMR]

+Rien Nafoutre I still own a kx250 2 smoke. I do like the power delivery of the 4 strokes.

[@mitchharris8545]

Hey sorry I'm late to comment just kinda curious, how did the rebuild go?

[@SOLDOZER]

One thing I do is put everything I take off in a bag and number it. Then when I go to reassemble, start with the highest number and count down as you put parts back on.

[@HTMR]

I bag everything and sharpie the contents. I lay everything left to right on workbench (same as numbering everything). Good tip BTW.

[@TiberiusStorm]

Yup they taught us that in school when I took a motorcycle technician program.

[@perkformance3502]

I have an 06 rmz250, I am having a hard time finding 06 main case for it. So my question is will 04-05 main kx250f case work on my 06 internals? Looking to reuse the transmission part with new baring, crank and piston. Really need the case any help would be greatly appreciated.

[@bonsai7438]

...excellent process... will avoid some troubles during re-assembling...hehhehe

[@sparkyrosatch2770]

I've rebuilt quite a few motors and after watching this I can confirm next time I'll be using a metal bar in the swingarm bolt hole when needed 😅😎👍

[@FrankA-973]

How do you remember how it all goes back together...so many parts! I love your videos..one of them helped me rebuild the forks on a kx125 I had. Fantastic KZbin channel..A+ Always Matt !

[@SOLDOZER]

I put everything I take off in a bag and number it stating with #1. Then when I go to reassemble, start with the highest number and count down as you put parts back on.

[@scripttfn7802]

I’ve got the same problem on my 06 250F lol insanely happy with you showing me this

[@twistthatthrotle]

Good for you for learning how to do this stuff, you will save a ton of money working on your own bikes and I'm sure these videos have helped other people too!

[@HTMR]

+Reid Ruland You got that right!

[@donaldcoalson4347]

👋, trying to figure out orientation of snap rings on trans main shaft, they say in book flat side/ sharp edges towards thrust load?? Would appreciate any help!

[@MsCrf450]

Your videos are great and you are great at what you do. The ownly thing is you dont upload every week which would be good if you did. Would like to see a workshop tour and toolbox and tools set up you have. Love the videos buddy.

[@HTMR]

Thanks Greg. I do this in my free time. I have a full time job, my wife works part time, and we have 3 kids under age 7. I repair bikes, edit vids, and write blog posts at night and early in the morning. I wish I can post more often, but it takes an insane amount of work to put this stuff together. I have vids that I filmed 2 years ago that I need to edit and upload!

[@brandonquenneville7330]

Reading comments below is just as entertaining as the video!! :). It's not as easy as it looks. Every engine has a different mind and attitude! Go peeps and collect your tools

[@mattunsworth8050]

At 18:45 is, the correct way for the rotor on the scavenge oil pump is with the dot facing out from the motor correct? Very hard to tell from the video

[@HTMR]

Yes.

[@FabioSalvasohn]

Question to the Tool at minute 13:09 . Can you tell me what it exactly is?

[@HTMR]

Flywheel puller.

[@matthewmarrs6062]

I have oil coming from the crankcase breather tube what could cause that?

[@dantsy6397]

8:11 what about the valve spring retainers?

[@HTMR]

Valves were not removed.

[@evanwilliams2602]

Do you need to take out all that shifting stuff on the right side case only if u are replacing the crank? Seems to me like u eouldnt need to.please let me know what you think I am doing a crank on a motor like this Suzuki thanks

[@HTMR]

If you are going that deep into a motor, it would be silly not to take it all apart and inspect and replace bearings etc...

[@evanwilliams2602]

@@HTMR well heres the deal.im replacing a crank in a 2016 rmz250 for a guy I've done some work for in past. He kinda wasnt expecting a rod bearing failure.so between top end n bottem end rebuild + bearing and crank seals I wasnt to replace any transmission bearing or seals ect. I was more less wondering if I can split the case.pulling from the stator side replace bearing ect pull the cranny through with my puller.knock crank out the other side while leaving transmission stationary. I'm a little shakey in the transmission dept and dont want to mess that up.so I was wondering if I can replace crank without touching trans.thank you

[@devonbrown34]

What kind of solvent do you use to clean? Do you just use compressed air to dry?

[@HTMR]

I use a stoddard solvent. Mineral spirits works well also and is cheap. Yes, compressed air to dry along with some time to air dry.

[@johnduvall5]

Howdy, donated on your site. If I am just replacing the crank and rod, do I need to take out all of the other gears on the clutch side? The oil pump and the shift drum... can I split the cases at this point , pull the crank, clean the oil screens, remove all the piston shavings. Put the new crank in and close it up?

[@johnduvall5]

Scratch that. Was nervous but wound up taking them all out. Going to clean and rebuild now. I would up finding two orings the size of my ring finger. I have no idea where they came from or wheee they go. Maybe the sprocket?... gotta look at that service manual and watch your rebuild video for the 5th time tomorrow. The wise I garage buddy kits or the hotrods kit, which is better?

[@HTMR]

@@johnduvall5 Yes I'd recommend taking all apart. I buy OEM parts, so can't comment on kits.

[@igortbp]

Hello, could get me some questions? I have questions regarding the size of the piston to put in place of the other, I would have to remove it and measure the cylinder diameter? after I know the size of that in the next exchange will be 0:01 mm bigger? Thank you!

[@HTMR]

Igor Vinicius Igor, if the cylinder diameter is not within spec, then you will have to send it out to get replated. If you want a larger piston, then you have to buy a larger cylinder as well.

[@igortbp]

So I will give an example, if the piston is original measure, in the next exchange piston prevention will be the same size and measurement?

[@HTMR]

Igor Vinicius If you have a standard (STD) size piston then replace it with a new STD piston. Measure the cylinder bore to make sure it is within specification. Also measure piston ring end gap.

[@igortbp]

Fazendo a troca correta a cada 50 Horas, costuma sair da medida STD? É que sou do Brazil e aqui não encontro peças com facilidade, ai tenho que pedir pelo EBAY, pelo seu conhecimento, altera muito o tamanho do pistão? é que sei que existe vários pistão com as medida A,B,C,D , sendo eles de diferença de 00.01 mm

[@HTMR]

Igor Vinicius Now I understand your question. You have to run the correct cylinder to piston clearance. Check the service manual for the proper clearance and calculate required piston diameter based off what your cylinder measures out at.

[@rickg1984]

Dose any one know on a engine bearing kit that covers all the bearings in the motor?

[@HTMR]

You are better off buying what you need OEM.

[@Tizzy_p]

Hey bro you still active I see you got recent vids but I’m doing a 2007 kxf250 same as yours but I have a crack in the case near the bearing housing for the gear shaft mate someone before me tried to ally weld it but it’s not a good job I’m gonna try and jb weld or alrodite it to make sure it seals but how did you deal with your detent or did you get a new case

[@Tizzy_p]

It’s my larger gear shaft bearing that has the crack through it

[@HTMR]

@@Tizzy_p New cases were used.

[@Tizzy_p]

@@HTMR I understand bro I’m gonna try and Bodge mine the whole bike owes me 150 mate so worth a shot lol any idea what sits in the right side crank case as in what oil sits in the crank side and in the outer case side I believe it’s clutch side as it’s the side with the oil filter I bright the bike completely stripped and wondering if I really need to seal the crack or if the fluid is the same between the cases which if so sealing won’t be a issue as long as it’s strong

[@Tizzy_p]

@@HTMR it’s defo right side it’s the side case that separates the crank from clutch basket if you get what I mean

[@trevorjacobs9258]

I bought a 08 kx250f back in early November for the same price as your buddies. All was going well, I was doing regular maintenance and checks before and after my rides. However, I started noticing it was burning a lot of oil. Is it time to install new rings? If so am I better off doing it myself or having a second party rebuild it? And does your part 2 of 3 video walk through this?

[@HTMR]

+Trevor Jacobs Trevor, does it burn oil all the time? Or when the engine is decelerating? Is it white smoke, or blue smoke? Part 2 does cover piston/ring install. It does not cover cylinder head inspection or rebuild. A head rebuild if required is best sent out to a machine shop to have looked at.

[@trevorjacobs9258]

+MatthewMCRepair It seems like I have to put oil in it after every ride, so I'd say it's burning oil all the time. I don't know if I would call it smoke. It's more like a very faint cloud of white smoke.

[@trevorjacobs9258]

+MatthewMCRepair It doesn't smoke like a two stroke, but before it gets warmed up there is a little bit of white(possibly blue?) smoke when I rev it. When it is warm enough to run nicely without the choke, the smoke goes away. Previous owner claimed it had the top end done.

[@HTMR]

+Trevor Jacobs How much oil are you adding between rides? Make sure none of it is spewing out the breather hose, as these models tend to do that sometimes. Moving forward, you can perform a leak down test and see how healthy your engine is. Five percent is considered perfect on these engines. Here is some info on leak down testing: www.howtomotorcyclerepair.com/motorcycleleakdowntest/

[@trevorjacobs9258]

+MatthewMCRepair I don't know the exact measurements of oil added between rides but I've had it where I was at the full mark and by the end of my ride I was well below the low tick mark. Thanks for the help, I'll check out your video on leak down testing

[@brandonquenneville7330]

Damn boy!!! Very well done

[@HTMR]

+Brandon Quenneville Thanks!

[@jessielifestyle2052]

I’m having trouble finding them 2 dowel pins for the cylinder head

[@GGT_GunGeekTactical]

Hey would it be the same with rmz250?

[@HTMR]

Yes.

[@GGT_GunGeekTactical]

@@HTMR I have a shit load of oil leaking from my 09 rmz mostly at the main seal right beside the back brake pedal what would you reccomend ? Do you do work for hire where are you located?

[@HTMR]

@@GGT_GunGeekTactical Email me a pic. I'm in Chicago and no longer do service work.

[@GGT_GunGeekTactical]

@@HTMRwhat’s your email bro??? I also noticed yesterday it was leaking from the crank case vent hose I have read that it does that when the filter may be clogged or the rings aren’t seated properly but it was just rebuilt and runs great 😫😫 but yea what’s your email bro

[@HTMR]

@@GGT_GunGeekTactical howtomotorcyclerepair.com/contact/

[@TrillasAdventures]

my 08 kx250f keeps gnaring up cams and cam journals. I've come to the conclusion that oil isn't making it up to the top end.. idk either oil pump or blockage in the oil screens behind the transmission...but don't have the knowledge to feel comfortable to split the cases. this video definitely boost my confidence..any advice or insight?

[@HTMR]

I would probably disassemble the motor and inspect screen and oil pump like you mentioned. Check every passage the oil takes to the top. Also, inspect the cam journals per the service manual which you can get for free on my site.

[@tictocpops1_276]

I have a 2004 RMZ250 that leaks coolant from over flow by radiator cap when it gets hot and starts spitting and spurts could this be a head gasket?

[@HTMR]

Did you leave a little room for coolant expansion when filling up? Will it eventually stop puking?

[@calebrose2031]

ik this is a old post but i am having trouble getting the primarydrive/rightside of crank nut off thats reverse thread i have heated it up and used a impact even used a really long cheater bar but it wont come loose i have been using the penny trick to keep the gear from moving but the nut wont break loose btw my bike is a 2007 rmz 250 so roughly same engine as this one any suggestions is appreciated

[@HTMR]

How much heat? I'm asking since there may be red loc-tite which requires 550°F. How strong is impact? Use shortest socket possible and try again.

[@TROLLxBAIT]

Hi I have a question. What do I need to to if I have a 2012 kx250f that leaks large amounts of oil out of a little hole on the right side of the top end? Some say i need to replace o-rings around the spark plug that were blown out due to overfilling oil. Any ideas?

[@HTMR]

+ReturnOfTheBait Sounds like you have a valve cover leak.

[@alextaiyanides9938]

How similar are these videos for a 2007 kx450f ?? If I follow along should I be alright or are they drastically different?

[@HTMR]

They are different, however a lot of the same tools and procedures are the same.

[@docfam78]

Just a question on the cam chain stopper plate. When you removed this, is the plate straight or does it have a factory curve to it? I can't really see in this video as it is whisked away quickly haha

[@HTMR]

docfam78 Can you reference video time so I know what you are referring to?

[@docfam78]

Hi Matthew. Thank you for responding. I solved the problem by buying the new part anyway. And the answer to my question is no. The part does not have a factory curve to it and it is completely flat. Mine appears to have been bent and gouged out by the cam chain grrr. The time was 13:32 but thanks for the very imformative video. Cheers

[@HTMR]

docfam78 Glad you got it figured out.

[@carterfreed7173]

Hey, do you rebuild motors? I got 09 kx250f it blow up person I bought it off f did a shity job t At rebuilding it. It needs one cam, came chain, top end, all the buckets, shims, and all the valves. Or could you give me a link to all the parts cause i can't find them. Thanks Carter.

[@HTMR]

Carter, I do motor work however shipping both ways usually kills the deal. Where are you located? All parts can be found on an online OEM parts finder. Try rocky mtn atv.

[@carterfreed7173]

MatthewMCRepair Mount Union, Pa

[@HTMR]

Carter Freed I'm in the Chicago area.

[@carterfreed7173]

MatthewMCRepair okay.

[@976Films]

Hi, I have a 2009 kawasaki kx250f, and I have a few questions... One is that the bike will not start cold with it on choke. I feel like it runs really rich because when I first start it whenever I crack the throttle it bogs, but when it warms up it is fine, and it has the stock jetting. I currently have the bike torn apart for jetting and to give it a nice cleaning. Also while I was taking the carb apart, there seems to be a rubber seal and washer that looks to go on the needle jet, but maybe I mixed it up or something. And my last question is, is a lot of valve noise normal? The guy I bought the bike from put new valves on it and he said a certified mechanic helped him through the whole thing... Any info or answers to these questions would be very much appreciated!

[@HTMR]

976Films, Try adjusting the fuel screw: How-To: 4 Stroke MX Fuel Screw Adjustment YZF CRF KXF RMZ FCR The bog is a lean bog. Are you referring to the fuel screw o-ring?

[@976Films]

MatthewMCRepair Okay thanks! And I am pretty sure I am referring to the fuel screw o-ring, after looking at part diagram after part diagram, that seems to be what that is... Thanks so much and I will let you know if all goes well adjusting and putting everything back together!

[@HTMR]

976Films Great. Let me know how you make out.

[@976Films]

MatthewMCRepair I got the bike together and it runs great! Thanks!

[@HTMR]

976Films Nice!

[@saqibnawaz5139]

Vry nice& methodical disassembly of all d parts of engine

[@6kx250]

everytime Im trying spec tight the tensioner some weird things happen either cams rotate or flywheel, please help Im about to burn this bike i've tried about 8 times already

[@tictocpops1_276]

6kx250 buy a new 1

[@davidmcghee4907]

Would like to see you doing this with kx250f 2010, I am just about to break my top end down and replace valves.

[@HTMR]

David, I'll add that request to my list.

[@davidmcghee4907]

This is my first time wish I could do it like you lol save me so much money. But I know the only way to learn is getting the tools out, regards all the way from scotland

[@SnipingWithSkillz]

I have my cases split on wr450 2004, for some reason if i turn the drum to shift through gears its almost impossible, but it works on a honda, is there something wrong with transmission or its just different make?

[@HTMR]

Do you have the detent mechanism in place? Are you spinning the shafts?

[@SnipingWithSkillz]

@@HTMR as the cases are open the dentent arm cant be installed,.but installed detent start for more leverage with my hands, yes im turning the shafts. In the manual it says in possible but in one rockymountain video on a different yamaha bottom they wasnt able too

[@HTMR]

@@SnipingWithSkillz What you are doing is very difficult to do. I put the cases back together, install detent, THEN shift it through the gears. If the shift drum is slightly out of position, then the gears will lock up.

[@kylelangworthy9641]

I have the same exact bike o4 rmz250 do you rebuild customer bikes if I was to send my motor I would love to have your knowledge rebuilding my engine

[@HTMR]

No not at this time.

[@brianpoindexter254]

What size is that bolt at 16:52

[@HTMR]

Not sure, this was 3 yrs ago...LOL

[@BluemoonChampions]

I have an rmz250 05/06, basically the same as the kxf 04/05. My bottom end has a tapping sound which is quite loud when cold, due to the exspensive costs of rebuilds on 4 strokes I was thinking about giving it a go myself and taking my time? Would this actually be possible or would it just be worth paying somebody? I'm not sure what tapping noise actually is

[@HTMR]

Yes, the RMZ is the same, and actually need to edit the vid title. I also have the service manual if you email me here: www.howtomotorcyclerepair.com/contact/ Try and locate the sound with handle of screwdriver to ear and drive end on engine. Hopefully you can pinpoint it before you disassemble. Yes, do it yourself if you want to save money.

[@KL6.7]

MatthewMCRepair what about a 2007 rmz 250 motor in compairison to this one

[@HTMR]

Similiar, cases are different I believe. The video will be applicable to you.

[@Stanman121]

Haha 14:00 True, true. I really really dig your vids. Make me want to learn my bike inside out. But I'm such a noob... lol.

[@joshuaabraham7862]

would I have to take out the whole motor to do a top end rebuild? Thanks!

[@HTMR]

No.

[@khenpaulw311]

Did you reuse the transmission bearings? Doesn't the removal process ruin them? Isn't it worth replacing them while you've got it all torn down? Thanks for the great video!

[@HTMR]

I replace any bearings that are worn or feel "crunchy". Otherwise you can reuse them. Definitely replaced the main bearings.

[@Atvracer357]

I want to rebuild my 2011 kx450f engine will this video work or are they totally different

[@HTMR]

No, it's different.

[@patrikstolt8366]

Hello, love ur video! I have to split my KX250f ´05, is this the right video? Or is it a different engine on ´06 like in ur video?

[@HTMR]

+Patrik Stolt Patrik, this video will be the same for your 05. Good luck with your rebuild!

[@patrikstolt8366]

Okey thank you. Im gonna buy ur second video for sure! I have found metalchips in the oilfilter. So i have to take all appart and see what it is. The metalchips are magnetic. What are ur thoughts?

[@HTMR]

+Patrik Stolt Hard to tell w/o looking at it. Send me some pics.

[@ashtongreensberry4417]

I have an o4 rm250z is there a difference, and if I use an Yamaha head on Suzuki?

[@riley_reed]

What year is this motor? Mine is a 2006 kx 250f

[@HTMR]

2006

[@codyerickson6250]

does he still have the bike i have a whole bottom end thats in peices for sale 50 bucks

[@jaredjones87]

Cody Erickson still have

[@MotorHeadGreg]

I really appreciate the time you took to go over every detail in this video series. I bought part 2 on your website. I have one question: did you buy all of the parts oem or did you buy a total rebuild kit? They sell a wrench rabbit kit on motosport that includes all the seals and bearings plus top and bottom end. What's the better route?

[@HTMR]

I went OEM. I would suggest you do the same. You pay a bit more however quality is better for sure. BTW, thanks for the support.

[@SOLDOZER]

Always buy OEM when possible.

[@jupiterjack2672]

How detailed is the second video and does it go through all of the torque specs

[@papa67510]

hello thank you for your video but where is the part 2

[@HTMR]

moi moisson Part 2 is available for purchase here: www.howtomotorcyclerepair.com/kx250ftopbottomrebuild/ Thx Matt

[@justinscott3999]

+MatthewMCRepair LOL

[@romulomartinez7931]

for my suzuki one of the best engines are simple without extra things like counter balancer, rocker arms or other things that honda and yamaha have.

[@alexsgarage01]

extra things like counter balancer are actually worth having as they drastically reduce engine vibration which helps with rider fatigue. Additionally, rocker arms are used in uni-cam engines (like some hondas) which are actually easier to build, remove and maintain. Lastly speaking from previous experience I find hondas and yamahas to be the most reliable, and this is coming from someone who has owned suzukis kawasakis hondas and yamahas. Just my opinions and personal observations

[@PCGamingNET]

My 2009 Kawasaki kx250F idles way too high? What's the problem?

[@HTMR]

First try adjusting idle screw if it has always idled high. If this issue came up recently, check for vacuum leaks. Here is a vid on fuel screw tuning: How-To: 4 Stroke MX Fuel Screw Adjustment YZF CRF KXF RMZ FCR

[@joejones711]

what video edit program do you use?

[@HTMR]

Windows movie maker. It's free and easy. As you can see, nothing fancy in my editing.

[@joejones711]

Thanx man

[@andressimon1531]

In which engine you find more quality??? CRF KXF YZF RMZ???

[@HTMR]

+Pelado Cuervo I haven't worked on any RMZ's, so I can't comment on that model. The KXF and RMZ were the same from 04-05. I'd have to say I never seen any failures on the YZF's, so I think they are more bullet proof than others (motor wise).

[@Sinkey101]

Where is part 2?

[@HTMR]

Full video - gum.co/dvEoC

[@1timberwolf8]

yeah same bike little newer but i bent a valve and so i need a new piston and also a completley new head and yeah know anybody who has a used one for an 08?

[@HTMR]

I don't have any used heads. Try ebay or forum classified.

[@JayFeuerherm]

If I were to send you my 2006 KX250F motor would u rebuild it? Please get back to me

[@HTMR]

Shipping costs do not make this cost effective for you. Also, I like to have the whole bike to make sure it runs good, no leaks, etc. Where are you located?

[@JayFeuerherm]

Montana

[@andyjonson9760]

Why clean the motor whilst the bearings are in??

[@SlammedBeretta]

Why not, You can always remove them afterwards if they need to be replaced. Removing all the oil and crud out of them lets you better inspect them!

[@HTMR]

In some cases all bearings do not have to be replaced. I inspect them after I clean them and make the call then.

[@igortbp]

Years bike?

[@hasanfarahani49]

Good

[@notsnho]

Is there anyway I can send over my whole engine and pay you to rebuild it lol

[@alexo896]

1950

[@saptayudha119]

i'm sorry i just want to tell you about my bike my bike is broken and I don't have anything to repaired ..the spare parts is very expensive... anyone's cant help me ? can i borrow some money to fix it?

[@thedocta80]

LOL @ trying to charge for 2nd part

[@HTMR]

thedocta80 Yeah, I'm LOL all the way to the bank. You won't be LOL when the shop hands you the bill.

[@elijahcollier1385]

@@HTMR could literally just look at my manual (for free) and do this no problem.

[@spawngaming4302]

Hello my friend I sent you message+ video on Facebook can u answer 👍

[@HTMR]

Email me here: howtomotorcyclerepair.com/contact/

[@bisnonnocanapa]

ha broken shift detent?? bye bye kawa you'll never see me!

[@HTMR]

Yes, I have another vid which pops open the RH case to show what happened.

[@HTMR]

I'm TheSteadyCamel You are correct. Definitely a design flaw. I've read threads where this happened to a few people.

[@XxscootskatextremexX]

yup definitely cant do this

[@HTMR]

That is exactly what I said before I ever did my first bottom end. You CAN do it.

[@XxscootskatextremexX]

MatthewMCRepair but if i mess up its the engine pretty much gone, unless i bought a cheap spares and repairs bike purely to learn...

[@HTMR]

Bruce Lee Don't have that attitude. With the service manual and this vid, you CAN do it. I've had so many people attempt their first bottom end with both my KXF & CRF vids. They are up and running and saved a ton of money.

[@XxscootskatextremexX]

MatthewMCRepair ok il try it when my engine needs a service wish me luck !!