Motorcycle Top End Rebuild for Four-Stroke (Part 2 of 2)

[HondaRider342Q]

I have a 2005 crf250x that i ran dry on engine oil so i adjusted the valves and it runs but should i do a top end rebuild new valves, piston ect... And can i just hone the cylinder on it?

[RockyMountainATVMC]

@HondaRider342Q - you would need to pull it apart and inspect it. then go from there.

[ollybb12]

Couldn't you have gotten your valves adjusted when you sent your head off?

[yittymitty11]

@ollybb12 you would check just incase they didnt do them

[sejlefrew]

ktms are a beeech

[RockyMountainATVMC]

@sejlefrew - this 4-stroke is by far little more work than most I must admit.

[PureN3WZ3ALAND]

@RockyMountainATVMC

i have an 07 kx250f and i heard that your supposed to have it rebuilt ever 40 hours

is this completely necessary or would i get away with just getting the valves done?

[RockyMountainATVMC]

@PureN3WZ3ALAND - a lot of factors play into that. regular instection is a good idea.

[hanratty450]

took everything off to do the top end???? lol next time take the tires off

[Occraracer10]

Good viedo but start the bike next time!;)

[MrKinghuman]

this guy has experience and makes it look easy. if anyone plans on doing this themselves make sure its a bike you can afford to screw up on. good video though, but i was disappointed he didnt turn the bike on

[njpaul78]

Great vid! im attempting a rebuild on my 07 wr 450, when i get to reinstalling cams and timing how do i hold TDC? i dont believe i have that locking screw anywhere, how can i make sure it doesnt move while i put the chain on the cams? thanks!

[RockyMountainATVMC]

@njpaul78 - no locking screw. just timing marks on the cam gears and flywheel. Easier than this KTM.

[njpaul78]

@RockyMountainATVMC---- Great thank u!

[pugsthomas]

Whew... This whole 4-stroke operation make me a bit dizzy...@_@

But thanks for the tutorial :)

[azri3081]

what a nice piston work....:)

[hdidane00]

i look on ur web site for an appropriate torque wrench but only dounf the spoke wrench can u provide a link for the appropriate torque wrench?

[RockyMountainATVMC]

@hdidane00 - any auto store will sell them.

[RockyMountainATVMC]

@hdidane00 - No locking screw on your WR. you needto line up the timing marks on your flywheel. Pull both caps off the cover to do this. Your WR is much easier than this KTM.

[andresarango22]

what would happen if you only place on ring instead of two on oil ring expander ??

[wq1299]

How often do fourstrokes need to be rebuilt?

[druminsk8]

@wq1299 i just did mine it started to loose compression on it's fourth year

[sk8perez2]

could you make a video on how to replace a tranny gear on my raptor 660?

[RockyMountainATVMC]

@sk8perez2 - Most likely not. The steps are similar to those is this video.

[TroyLeeDesigns872]

Wheres the valve replacement video, i need to replace mine they need to be replaced cause theyre so old

[stevensj13]

Torquing is for losers lol, just kidding. For me theres 3 settings, finger tight, snug, and tight.

[meda789]

@stevensj13 lol most ppl agree with u thos torque renchers rnt cheap

[qwerbait5000]

Emoskater1212 it's called u have a 2 stroke they smoke like that and there not really supposed to idle very good lol

[SoobaaSteve]

how much would it be to do the labor for what you did to this ktm?...and including the parts.

i have a 09 kx250f

[RockyMountainATVMC]

@SoobaaSteve - You need to call a shop in your are to find out. But why not do it yourself?

[ridinhonda4life]

hey i got a 85 honda 200s 3 wheeler. bout to do rings and gaskits but do you have to adjust the valves when ever you do rings? my funds are limited and rings are the primary need right now. so i just need to know if its manditory when you do rings.

[RockyMountainATVMC]

@ridinhonda4life - There is no real relation between the two; however, You should check the valves and adjust them.

[ridinhonda4life]

at 2:25 you can here a phone ringing if u listen closely

[DRUNKINSKATER]

This is ridiculous. I can't believe how many people opt for four strokes when they are so complicated compared to a 2-stroke.

[Killgore521]

After seeing this i'd rather stay to my 2 stroke :D these are alot easier to maintain in my opinion. It looks like there's so many things that can go wrong while doing all your steps :s

[JOCKATEO]

for off road i dont like 4 strokes as i just dont like the sound plus they just dont have that feel of power a 2 stroke has but thats what i think plus i am old skool

[Premixoctane]

@JOCKATEO lol thats fuckin true dude!

[2hot4you369]

Thats a clean KTM, 450?

[RockyMountainATVMC]

@2hot4you369 - yep. 2004 EXC 450. not real clean anymore. It has been used and abused by one of our employees!

[emoskater1212]

@RockyMountainATVMC how do u find top dead center

[BowHunt1229]

do you think that just plain ol seal maker would seal up a split case sufficiently if its already bolted together?

[RockyMountainATVMC]

@BowHunt1229 - Already bolted together? no. Some case halves use a liquid gasket maker instead of a gasket, but it has to be pulled apart. If your bike requires a gasket you must use one.

[emoskater1212]

@RockyMountainATVMC how do you know when u need a new top end besides compression loss

[RockyMountainATVMC]

@emoskater1212 - refer to the manuals recommendations for replacement. Don't wait till something breaks!

[emoskater1212]

@RockyMountainATVMC i bought my bike used and the guy didnt hav a manual do you know were i can get a 07 rmz250 manual and if my bike idles for like 2 or 3 minutes then rev a little white smokke will ccome out of the exhaust do you know what that might be

[yz100f]

my yamaha 1979 yz100f 2stroke says book 1 on top of piston and has like a 13 digit number on top whats this mean standard? arrow faces exhaust tho dood

[kraden18]

Hey i am messing around with a motor from a ltz250 atv and i am having trouble with the timing. Do they all have some way to find tdc with using a notch in the crank? or are all bikes diff or most?

[RockyMountainATVMC]

@kraden18 - refer to the manual. there should be a mark on the flywheel that matches up with a mark on the cover.

[kraden18]

@RockyMountainATVMC yeahh i dont have a manual unfortunatly.

[Burkecss]

 !!!!!DEERMAN IS A NOOB!!!!!!!

[deerman1212]

when you install new rings does it matter where they sit on the piston? like where the gap on the rings are on the piston?

[jman5630]

@deerman1212 Yes. Stagger them so they will overlap one another.

This will prevent oil from leaking into the combustion chamber.

[crb300ex]

for the water pump cover could you use silicone or high heat silicone for that

[ch0l0sk8r]

i was wondering if your susposed to put silicone on a 96 kx250 head gassket, need to no asap thsnkd

[RockyMountainATVMC]

@ch0l0sk8r - a new gasket doesn't require it. It may not hurt though.

[two45triox]

@ch0l0sk8r Do not use silicone, and do not re-use the gasket, they are squash type metal gaskets.

[johndevinaspre676]

hey so this is probubly a stupid question but i dont know it do you have to like do anything after you empty you radiator or can you just fill it back up with coolant like i dont know if you see what im asking its hard to explain.

[RockyMountainATVMC]

@johndevinaspre676 - Just fill it up.

[bmxty82]

WTF.. There's no wrist pin bearing for the piston??

[RockyMountainATVMC]

@bmxty82 - Nope. most 4-strokes don't.

[ViolentEncounter]

@bmxty82 cuz the oil being at the bottom, always in the wrist pin?

[sidhucer00789]

im going to practice on a lawnmower LOL

[171apples171]

so can can i bend a feeler gauge at the tip so i can get it in between there to adjust the valves on my GS300? I have the bladed feeler gauges but they are straight and wont clear the top of the head where the valve cover gasket surface is.

[RockyMountainATVMC]

@171apples171 - yes, i bend mine all the time!

[spruland]

is there no small end bearing on 4T's?

[RockyMountainATVMC]

@spruland - not usually

[RM250D8rzr]

when or how often should the head be re done and valve seats cut? when the valves need a second shim? and replace valves and cut valve seat or?

thanks

[seasonedtoker]

maybe it's irrelevant but I was taught that circlip gap orientation should point either up to the piston top or down to the crankshaft. just a thought

btw thanks for your videos

[burningsociety]

Great video guys very informative

[kasenut12]

what type of grease (lube) did you use on the lobes?

[miniimoto95]

now i really hate KTMs...

water pump in the head... having to disassemble the head before you can remove/install it.... a bolt that's that close to your crank.... allen heads....

[andre1995ish]

these vids help so much... to bad i cant aford the parts to do this because my bike needs this done bad

[highdeserthater]

you should use red coolant. its less corrosive than green. :)

[rebeldawg1985]

this is the exact reason i will never buy a 4 stroke. 2 strokes for life!

[katokid24]

I am confused my bike was dripping oil out from behind my sprocket and i dont know what to do does that mean the counter sink seal has just had it or is the hole bearing screwed ?????

[89Silhouette]

my friend has a yz450, he was riding along gunnin it & then a big puff of blue smoke blew out the exhaust, then it stalled...

@ 110hrs without a rebuild, im assuming he's blown his rings?

[makeminealarge1]

excellent video

[cat123456789101]

looks like a major pain in the but to do all that

[qwikyking]

i'm unable to find the bottom part of the cylinder head on online sites, would i be able to get it from a dealer? would it be under $400?

[RockyMountainATVMC]

@qwikyking - I have no idea what you are looking to buy. Are you talking about a cylinder (that is below the head)? What machine?

[qwikyking]

@RockyMountainATVMC a head without the cams and everything in it, just the basic piece, its for a 450 ktm, its got a big knick in it, the guy who is selling the bike says it would prolly have to be replaced

[Torern88]

This is like ajusting a piano compared to a two stroke :D

I was thinking about buying a 4 stroke but after seeing this I think I will go for a yz 250 two stroke.

[kcb13]

@Torern88 I was thinking the same thing! except i prefer cr's haha

[scrimmy6969]

@Torern88 ktm is a difficult bike to work on

[highdeserthater]

@scrimmy6969 naaah. i only would (and have when repairing the neighborhood bikes) struggled with all of those damn hoses and fuel lines. but everything else is pretty easy. working on anything built after 2000 is hard though compaired to good ole 20th century bikes.

[9139475]

Wy don't you change cam chaine?

[RockyMountainATVMC]

@9139475 - you certainly could, but this one was fine.

[9139475]

@RockyMountainATVMC

Yes it's a good reason!!!, but I just wanted to see how we did because I need do it on my 04 ktm 450 exc. Thanks for this video. (9139475 from belgium)

[mycat8urskidoo]

Will the Tusk Chain riveting tool do the trick on the RFS motors or would you recommend the motion pro

[RockyMountainATVMC]

@mycat8urskidoo - they are pretty much identical kits. The tusk works great.

[shotox21]

THANK YOU

[halosavage]

jesus crist, this is a complicated job

[penc5use3]

Awesome piece of work! It seems incredibly confusing to me. How come you know which bolt goes in which hole! Which brand's engine is easier to go for this kind of rebuild? Honda, KTM or Husky? Very best to you!

[RockyMountainATVMC]

@penc5use3 - I think the KTM is harder. a few more steps than the Japanese bikes.

[ed563]

the video says to watxh the valve replacment video.... i cannot find the link to that vieo, can u help me find it? thanks

[RockyMountainATVMC]

@ed563 - it doesn't exist yet. My hard drive failed and I lost the video. I will make a new one someday. sorry about that.

[nordyk2]

Thank's for video. You very help me !!! Thank's

[anezka15]

hey i am just wondering what do you mean on 7:14 7 :30 minutes. what kind of measurements. ??? i am trying to fix my motorcycle.. your help and fast answer would be very helpfull. thank.. you

[coshyno]

wow thats a huge tank

[coxboyentertainment]

how come that piston is so short

[coshyno]

@coxboyentertainment its a short skirt piston

all newer performence 4 strokes are like that

[j58400]

super

[deathslayer0102]

how long should you wait to rebuild your topend?i have a 2006 crf 50 withh a big bore kit 88cc but i got installed in 2007 how long should i wate

[RockyMountainATVMC]

@deathslayer0102 - there are several factors here. it depends on how hard and often it is ridden as well as how often the oil was changed and whether or not anything got past the airfilter. Refer to you manual for recomended inspection and rebuilding intervals.

[iplaywow555]

never had to rebuild a 4 stroke..

[turbosmith45]

Just wanted to say thank you to RockyMtn for taking the time to make a well made very informative video. I've saved it to favorites for when I need a rebuild. You guys always seem to have great values on tools etc..

Could you please do a valve adjustment video for the KTM RFS, and finding tdc without the crank bolt. maybe the oil change filters and screens, and air filter service should be included in that as well for people that don't know.

[lastaferyn]

Awesome stuff guys, you mention in the video a valve replacement video which I cant seem to find.

[RockyMountainATVMC]

@lastaferyn - I lost the file and have to make a new one. sorry

[1727267241]

do me a fever. never remove this video

[zobel929]

ya i replaced the outside one because the tusk kit had two different oring sizes and one seemed to big for both grooves. do the orings need to be a real tight fit around the two grooves?

[RockyMountainATVMC]

@zobel929 - no, you just need to get them in there.

[zobel929]

i took the head cover back off and the 4 head bolts were not tight enough. But now the only place where there is a leak is out of that little bolt hole right next to the lower right of the water pump cover. it wont stop drizzling out of there

[RockyMountainATVMC]

@zobel929 - did you replace the O-rings around the water pump? It sounds like they may be bad.

[zobel929]

I just rebuilt the same engine as in this video. It starts up and runs great but out of the bottom cylinder gasket it is driblling oil out and the top has anti freeze seeping out. Ive used new gaskets and installed them correctly with yamabond. Could the 4 cylinder bolts not e tight enough? what do you think is causing this?

[iexploderacoons]

did you torque everything to spec? because that could do it, and did you clean the mating surfaces?

[RockyMountainATVMC]

@zobel929 - it could be the problem. you shouldn't have needed yamabond on the o-rings or the base gasket though.

[juoj8]

I have really enjoyed your videos, and they have helped me a lot to understand not just the models that you are working on, but working on motorcycle engines in general!

I think it would be great if you gave more "why's" to the "how to's". For example, giving short examples of what would happen if one failed to do some step in the procedure.

That way, if something doesn't work, tracking the problem down would be much faster!

Once again, thanks for outstanding videos!

[RockyMountainATVMC]

@juoj8 - thanks. We will keep that in mind on our new videos.

[fengluzon]

Great videos.

Thank you very very very much.

Why can't i see the valve replacement video?

Do you have a video for a wr250f or a yz250f? (450 will be great to).

Thank you very very very much for all the videos.

[RockyMountainATVMC]

@fengluzon - I had a valve video done, but my hard drive crashed before i rendered it. it is now gone. i will have to start over one of these days. No Yamaha video yet.

[Guitardudeadam121]

Brilliant video!! keep it up lads:) very helpful

[125tristan250]

oh it is

[importmac]

my kick start is stuck solid could it be a jammed piston

[RockyMountainATVMC]

@importmac - i suppose it could be that.

[acraze21]

How similer are these to let's say a 1982 Honda xr200 engine? I have no manual for it ( it was free) but I want to bring it in my room and tinker with it.

[RockyMountainATVMC]

@acraze21 - there are certainly similarities. Your XR should be a lot easier.

[aanderson66]

@RockyMountainATVMC i have never taken the time to look at the top end of a small 4 stroke. definately looks alot easier than the rebuild i did on my truck. with all the parts on hand i think a novice on wheelers like myself could tackle this in a weekend. thanks for the video. i will definatley look at picking up a wheeler that needs a rebuild

[rama6maiden]

taking of the parts to reach the piston looks more diffucult than changinn the piston!!

[RockyMountainATVMC]

@rama6maiden - i suppose you could say that about any part inside of an engine.

[rama6maiden]

@RockyMountainATVMC

hahaahah yeah thats true!!!

you guys rock!!!

[jeremyzdead]

Are you gonna do a bottom end for a 4stroke?

[RockyMountainATVMC]

Not unless my WR bottom end fails me.

[NiceSubaru]

Hey, have you got a video for a KLX250 or KLX300??

[RockyMountainATVMC]

Sorry.  no

[schnuper450]

how much does all of this cost?

[RockyMountainATVMC]

It depends on what "all of this" means. Check out our website for prices specific to your model.

[katokid24]

nice vid guys how much would somthing like this cost for someone to do it on a KTM250sxf

[beluga420]

I need a video for the CRF 250! but this helps almost the same thing as honda honda doesnt have the waterpump on top looks easier ty for the video Rocky Mountain!

[RockyMountainATVMC]

I have a CRF250 video, but I have not had time to finish editing. I will get to it soon.

[beluga420]

Well thanks a lot as soon as it is out i'm gonna check this out :)!

[rgrifle]

great about the crf vid cant wait you guys rock

[reco900rr]

I wish I had adjustable tappets for my WR.. That's nice that this bike has this valve adjusting style. Nice video.

[reco900rr]

Nice VID guys!

[marek0086]

to hell with these KTM 4 strokes!... get a Jap bike.... much nicer to work on.... and cheaper.

#1. Forgot to clean oil off (with solvent) of head gasket mateing surfaces!

#2 didnt say ANYTHING about positioning of piston rings.

#3. Never say anything about cleanliness!

Was this video for Entertainment?... or an attemp at an instructional video??

[technineriderTEH]

great work, it would be nice if you guy's put a video of rebuilding a kawasaki kx 450f though, Alot of my buddies would much rather watch your video's than read the manual's goofy pictures hehe ;) (plus we all order from you guys too)

Awsome vid Now do a kawi please!! XD :)

[lodi7777]

very nice vid the best i seen on youtube so far

[EarthTrauma]

Very well done. Clear video and precise instructions.

[trkjheruohjyehf]

great vid guys..carnt wait till u do 1 for the crf's thanks!!!

[tilex08]

it says refer to the valve replacement guideto replace valves, youguyus dont have a video for that!

[RockyMountainATVMC]

you are right. I am finishing the editing on it now. I should have it done soon. thanks

[krull196]

your videos are great i rebuilt my rm85 all by myslef by just watching that video on how to rebuild a 2 stroke engine

[RockyMountainATVMC]

Good job!

[krull196]

thanks

[ktmtomdux]

hay guys at rocky mountain my top and bottom end need to be re built on my kxf250 and i realy want to take it on myself but could do with a bit of profetional help could you please please post a vid of how to do it i am in need of help thanks guys keep up the top vids you post you always managed to help with my yz thanks again

[RockyMountainATVMC]

We are also putting one together for a crf250, but not a kfx250. The process is about the same though. It will be done in a few weeks.

[markr66]

You guys always put together great vids! Thanks!

[jozzilion]

Very well done and very-very informative.

Thanks Guys.

[PowerAaron123]

great video

can you do this with a yamaha yz four stroke

thanks

[RockyMountainATVMC]

We will be doing a CRF soon and then a YZ a little later. Just need to find the time.  thanks.

[PowerAaron123]

that would be awesome

thank you very much

your videos help alotttt

[mxchamps]

Great job! Thanks!