Honda 2-Stroke Bottom End Rebuild, Part 1

[enginemaster8]

what kind of pressure plate is that?? O.O

[bintwert]

you could have done one thing different;y,to remove the gear off the right end of the crank,leave the clutch basket on and put a washer between the basket and the gear and the loosen the bolt,the way you did it could cause some damage

[killer4life1000]

it looks like youve done this b4

[crf100person]

my brother just ran his yz125 with gas that he thought had oil in it but it didnt and now its messed up. a mechanic said it would need to be replated and a new piston, and i think he said that would be $1000 if they did everything, and if it needed a new crank rod it would be like 1300-1500..... doesnt this sound high to yall? but we would put the piston in ourselves

[Liberalsuck100]

@crf100person Dude i could rebuild your bike for you in 25 minuets.

[ed563]

@ 1:20 WTF were you doing to the clutch basket... destroying it?

[maxx268]

i have a 1986 cr 125 and im rebuilding the entire motor, i just got finished installing the gear shift drum and i noticed that neutral is all the way down and 1st gear through 5th is up. is that ok to run it like that or does neutral have to be beetween 1st and 2nd gear. can you please respond back to me on this.

[RonniesGarage]

@maxx268 neutral must be between 1st and 2nd!

[Mbomben]

Do I need to remove all the kick start gears, shift pawls, and what not if I am just replacing the Left crankcase? My crankcase is majorly cracked right between the flywheel and sprocket so I need to replace it because its too big of a crack for JB weld.

[TheMotokid187]

wow u have to be the worst mechanic if u even are certified , using a deep well socket with a extension thats incredibly to long , wow dude did u even remember how to put it back together or is it still siting in pieces in ur garage hahahahaha

[seafood360]

dude why the dramatic crap it aint hard to do dousebag

[420mattjz]

got a '93 cr250 2 stroke the crank case was unkowing running dry of oil and the bike ran high then died. when tried to start it just starts real fast and is abnormaly loud and just dies i was told most likely something went wrong in the low end any ideas anyone ?

[TheMotokid187]

@420mattjz yea low end bearings are prob gone and im sure everything in that motor is warped 

[DSMFORLIFE92]

how do you know if bottom end is bad i have a 2001 yz 250 and my crank moves side to side but not up and down. The crank moves side to side and hits on both sides is it bad

[RonniesGarage]

@DSMFORLIFE92 typicly side to side is ok but extreme movement in any direction means bad bearings pull your motor aprt pull the crank and im almost positive the bearings will need to be replaced. and besides most people only replace the bottom end when it goes and by then its a 50/50

whether or not the motors salvageable.

[MrBrap4life]

Recloose nice

[bdkxkid]

grave digger?



[davison1021]

hey if i have to crank my bike many times really quick to get it started with full throttle but once started i can start it no probe for like 24 hours and yesterday full of gas started coming out of the expansion chamber near th cylender? what would you say that is bad fuel mix or spark plug?

[NoPrEJudice201]

@davison1021  that shouldnt be happening get it checked out before you go riding again

[davison1021]

@NoPrEJudice201 i allreadt figured it out my expansion chamber didnt have the spring or bracket that holds the fleng and pipe 2gether well i was losing all my gas through there for all of you that have old bike from b4 81 good luck starting your yz w/o an expansion chamber spring SOMRTHING TO LOOK AT WHEN IT WONT START

[Sladur4e901]

THIS BIKE IS JUNK BECOSE ITS WITH ATM GEARS !!! :D:D:D:D::D: JUUNKKK!!

[TheHondaAbuser]

0:45 thats gotta be the gayest ratchet ive ever seen

[BlazeOfGloryOffRoad]

Rockymountainatv (dot com)

[joeydfromthepoc]

@ myblazeofglory where can i get a clutch holding tool i have looked for them and have had no luck on finding myself one?

[ethanfigge]

Well theres your problem......its a honda

[mably23]

@ethanfigge and what have you got?

[ethanfigge]

@mably23

YZ 125

[mably23]

@ethanfigge lol

[ethanfigge]

@mably23

Right back atchya

[tonewall1]

take 4 1ft long 2x4s nail or screw them together lay the motor sideways and life will get ALOT easier rookies

[JustRide626]

gotta love 2 strokes. way easier than 4 strokes.

[1987Honda250cr]

im am working on an old cr250r and being that at my age and this is the first bike i am working on i dont want to be an idiot and put 20 different parts from different brands while rebuilding the motor.... do you have any recomendations on what brands has the right parts for me to rebuild this bike, i have been looking at wiseco

[sweetvid345]

one tip you have to be very careful on the engine covers with the gaskets because then it's a pain in the a#$ to set it back.

[HondaSeth1500]

I have a 2009 kx250f and I have only rode it a few times. When should I consider a rebuild, what for, and do I need a whole new engine or certain parts?

[WetDirtProductions]

if you needed to get a whole new engine instead of a rebuild, nobody would be able to afford riding. Its usually only certain parts, for you probly Valves, Pistons, Ect. Deffinately not a whole new engine.

[MOBLEY49]

What is the brand of puller installer are you using to install the crank , the one I have isn't like that and is it universal for different years?

[k3ith2x23]

where can i find a new chrome fatty pipe for my 1982 yamaha yz 100, fmf dosent have it

[k3ith2x23]

the engine lloks like it was just recently rebuilt entirley, y wud u take it apart again??

[BlazeOfGloryOffRoad]

The bottom end hadn't had any work done on it for at least 4 years before this. The bearing had actually began to come apart taking out the seal causing it to burn gear/clutch oil like crazy. Go to our website for a before and after build tp see how bad it was. blazeofgloryoffroad. thanks for aksing.

[2fstmotox]

how do you take the bolt there at 1:21 when we do the clutch just spins

[myblazeofglory]

Use a clutch holding tool on the clutch to keep the clutch from spinning. If you look close you can see the tool on the clutch and wedged against the bench. It's like a big pair of vice grips.

[herse88]

@myblazeofglory wot year is this bike?

[gtyamaha]

hey im rebuilding a cr250r 2001 TOP END, and i took off everything needed, and the cylinder wont come off, the right side moves up and down a little but the left wont budge. i took off the bolts, reeds, powervalve, taped it and it wont come off. what do you tihk it could be?

[herse88]

@myblazeofglory Hi mate nice vid,is the jugs 4rm 00 the same as 01 cr250r model?

[musiclovr2]

you see the shiny metal arms thats a tool, you can get it off with a electric impact, or air,just when assembling it torq it to specs

[tomriddolls]

@2fstmotox you don't have to use the expensive clutch tool. I use an old fashion wood clamp and grab 4 of the 6 bolt posts, put a pair of vice grips on the nut and turn the grips with a screwdriver. you con't need anything too tight. it works great but is a little clumsy - if I rebuilt these for a living I would just by the clutch tool but for opening a case every one in a while the clamp method works.

[highdeserthater]

@2fstmotox you can also use an impact wrench and hold it tigght with your hands

[roost199]

@2fstmotox cold also use a impact gun

[craig562]

could anybody tell me how to bleed the air out of an oil pump on a road legal 2 stroke dirt bike and is it hard

[rgrifle]

just block it off and premix the petrol yourself there unreliable i had 2 fail and sieze the engine

[DaManzMoney]

I would like the other guy said block it off and mix ur gas and oil i always did even on a brand new

1987 Honda Big wheel 80

I bought back then but maybe if its a brand new bike your probally ok but ask aorund and look into it

[hondarider100r]

so many little pieces haha...top end i see is wayy easier

[krull196]

hell ya ive done one in like 1 hour

[highrisk9000]

how do you keep the inner clutch hub from moving when you loosen the locknut?

[highrisk9000]

or it may be called outer clutch hub like in the video, but im talking about the huge lock nut in the center of the clutch assy that you have to bend the tabs back on

[seanbluecash]

hes got a tusk clutch holder that is seated in the hub notches and locks like vice grips. you can see it in the vid

[wotracing22]

Got it all back together and............ It fired up the first kick! I'm happy. Ordered a few bottles of the Bel-Ray H1R and some temperature strips from RM. Do you run the recommended 40:1? I've always been a 32:1er / rich? Not sure if I broke it in properly. I just let it warm up for a few minutes and rode it around the block for about five. The guy from the engine shop said the rings should seat without any special procedure but check to make sure the cooling system was working. Trail time...

[dennissteakin]

32:1 best ratio

[wotracing22]

Ok. Picked up the head today. $225 all said and done (honing and piston kit). Lucky its a two smoke and didnt cost an arm and a leg! Slowly getting it back together and noticed i need another gasket for the vforce reed valve. Darnit! Any recommendations to break it in when its ready? Also the joint where the exhaust pipe and muffler meet leaks oil all over. Id rather not buy a $50 aluminum (T&M designs) coupler. Do you have this problem? Help is greatly appreciated. Thanks!!!

[myblazeofglory]

I just bought a replacement rubber sleeve for the exhaust..doesn't leak anymore. Just don't get the bike too hot and don't go too hard for an extended time, get it hot then let it cool for the first few hours ride time.

[wotracing22]

I just dropped off the top-end to Engine Dynamics. Its going to run me $200 to have the cyl. re-honed including the piston kit. Mike (the owner) said it was good timing because the piston was worn and showed some signs of siezure. He'll check to see if the head is warped also.

Question- What is your oil to fuel ratio? I was running 32:1 Honda HP2 Blue bottle stuff. Also what oil do you prefer for the gearbox?

Cool man- Thanks again for all the knowledge and documentation!

[myblazeofglory]

Nice! I run Bel-Ray H1R Synthetic and I love the stuff. It's more expensive, but you don't have to mix quite as much...It recomends 40:1. I run Bel-Ray gearsaver in the gear box. I'm planning on a full top end next season..re-plate etc. I appreciate the feedback and info as well.

Glad I could help..feel free to drop by the site etc. and talk shop anytime:) blazeofgloryoffroad . com

[Nk00037]

i need help my yz250 broke the kick start wont work how much will it be to fix?

[NoPrEJudice201]

@myblazeofglory Thanks for posting this my ktm sx needs rebuilt but scared to attempt it in case I mess up but seeing it done is better than just reading the manual,I could do a top end but bottom end rebuilds are beyond my mechanical knowledge.keep these coming its great to watch and learn

[wotracing22]

When i removed the cylinder I noticed the side to side play in the rod leading me to believe i needed to replace the rod bearing/split the cases. I then looked online and found your helpful info on how to do so. Now knowing that even new crank assembly's have play I will fix the top end only. To answer your question about the gear oil- No i didnt have to add oil in the gear box. I dont feel any play in the main bearings when i pull on the rod.

[myblazeofglory]

cool. Sounds like you're on the right track.

[wotracing22]

Originally, I intended on replacing only the head gasket because I noticed seepage where the head and cylinder mate. When the head was off i noticed that the last person "inside" didnt tighten one of the collared head studs enough not allowing a good seal(I hope the heads not warped). I then was able to twist the top of the piston with my fingers while in the cylinder leading me to believe it needed a new wristpin bearing.

[wotracing22]

Just spoke with Engine Dynamics in Petaluma, CA. The cr's have a plated bore. $300 to be replated. $45 to be re-honed. Nice guy on the phone. He'll let me know if its in spec and were to go from there. A new replated cyl. sounds ideal and more durable, but if its within the tolerances my budget tells me to have it rehoned. I'll drive there today or tomm after i get the power valve out and I will have more info for you soon. Cool.

[miketl1df]

2 stroke!:D

[myblazeofglory]

thanks for the info!:)

[wotracing22]

Thanks for the reply. This is good news! Looks like i will be installing a new piston kit and sending the cylinder out to be re-plated. It appears ill be back on the trails sooner than later. YES!! Also, is there anything i should know when taking out the exhaust valve besides clean the crap off of them?

Maybe one day we can hit the trails? Im moving to Denver soon and Utah is just a state away? Cool man- thanks again.

[myblazeofglory]

Cool! just clean it out and make sure it moves without binding and nothing is visibly broken etc. I'd like to re-plate mine soon and get a new piston..it was in spec, but just barley and it did have some visible deep scratches.

Who are you sending it to to get it re-plated?

By the way, do you remember having to add gear/clutch oil much before you took your bike apart?

[wotracing22]

I love the smell of pre-mix in the morning!

Question- I removed the piston and cylinder from the cr250. I am concerned about minor side to side play in the rod. No play whatsoever up and down. I read side play is ok. Not sure on engine hours. Also the cyl. wall has some imperfections. Is minor play ok and what is my best bet for the cylinder? Thanks for any info. The trails are calling....

[myblazeofglory]

Some side to side play is ok. Even with a new crank assembly there is side to side play. If no up and down play, then you are probably ok. It's ok to have some imperfections in the cyl. as long as it's in spec. The only way to know if it's in spec is to measure it with the correct spanner gauge, micrometer etc. The best bet to fix the cylinder is to have it re-lined. If it's only minor out of spec and minor imperfections, it's not too expensive and will give a better than stock finish/hardness.

[wotracing22]

Wow! Just finished checking out your blogspot. There is a bunch of valuable info for me since i ride the same bike. I really like your bed extender and tiedown frame and of course the cr250 info. I wish you were my neighbor. Haha.

[myblazeofglory]

Haha, thanks! I could use a neighbor that doesn't get mad for starting my bike on a Saturday :). Hope you keep coming back to the blog.

[rchp420]

2 smokers all the way!

[Paulstathis1992]

how often should u do bottom end rebuilds if u ride one day every week

[RCdude33]

I need ssome advice, well would you prefer a 2 sroke or a 4 stroke?

[ballsniff13]

four stroke is a lot better bcuz u have more power longer lasting u dont have to rebiuld all the time and they run cooler to so i prefure four stroke man

[HondaH100A]

2-strokes are not neccessarily easier and cheaper. Depends what you want. 4-strokes are cheaper to run and easier to live with, but 2-strokes are generally more fun and better performers. Interesting dismantling schedule. I have done many of these in my time. May I give a bit of advice? When locking up the crank, I don't use a metal bar through the small end eye (you can distort it, trust me, I have seen it done - not by me), rather, I place a piece of metal in between the primary and clutch.

[myblazeofglory]

Of course..if you are not replacing the rod you wouldn't want to do that. If you are replacing the entire crank and rod as I did then ruining the old one wouldn't matter too much eh.

It depends on what type of 4-stroke you are talking about I suppose..the newer high tech models are definitely more expensive to own and operate than a 2-stroke. My son's DRZ110 however(air cooled, very simple design) is very cheap to own and maintain.

Thanks for your comments!

[vampov]

2 strokes are where it's at! Thanks AMA for ruining a great bike.

[minidime92]

would you say that its easier to maintain a two stroke over a four stroke. because i want to trade my crf250 for a cr but want to know from someone who does their own maintance

[myblazeofglory]

2-stroke is easier and cheaper, for sure.

[yamit465]

Hi Sir

Thanks for this video, helps a lot indealing with "most of" jap. dirt bikes.

ps.: you must have a patient wife (or kids)

S!

[myblazeofglory]

Thank you, yes VERY patient wife and kids! :)

[blkout15]

your smart man..lol

i would get so lost.

lol this needs to be done to my bike too.

[martyr2]

dam i hope you know how to put that back together

[myblazeofglory]

LOL:) already there! Works great.

I have never tried just a rubber mallet, it's and interesting thought...I'm not sure I would have wanted to do it without a case splitter and I have 3 bikes, so the $60 isn't too bad for a universal tool for all 3 that makes the job easier. Thanks for the tip!

[randypittman15]

yes i a'm aware of what they look like (thanks n-e ways), i was considering buying one from rocky mountain but i have a large piece of 1/4 inch steel plate. i have cut a piece from it about 1' by 1', a small round hole cut in the middle and a nut welded in place to serve as the center of my splitter. then i just drilled some holes for the bolts to fit through to go into the case half for pulling...

[myblazeofglory]

Sounds like you're well on your way!

[TJScott2012]

just throwing this out there, case splitters are pretty much unecessary, if you have a rubber mallet, you can save $60.

not being a dick, just saying.

[randypittman15]

will you be using a case splitter or some homemade tool to split the crankcase?? i was just woundering because i am at that part and i do not have a splitter, and if you are using a h-m tool i would like to see how you made it...

[myblazeofglory]

I'll be using a tusk case splitter. I thought about making one, but for $60 you can't really beat it. It would be really easy to make one if you had some thick metal plate, some pipe, and a way to cut and weld it. I have all of the above except for an easy way to cut the thick plate. It just has three plates that pivot around a center bolt. The plates have slots so the bolts can be inserted through them and into the case where you need them. Then you tighten the bolt to pull the case apart.

[myblazeofglory]

I have a picture of the one I bought on my blog adress that appears in the video..just look for the bottom end rebuild from the home page. I'll try to get #2 posted asap..I am still saving $ for parts;)

[randypittman15]

hey, when are you gonna add pt2?...just wondering...i a'm currently doing a full rebuild of an 01' yz 125...nice so far though...

[myblazeofglory]

Thanks, I hope to have it up in 2 to 3 weeks. I'll be splitting the case and putting it all back together. Good luck with you're bike!