Added: 3 years ago
From: RockyMountainATVMC
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  • Hi i have 1998 kx125 that wont start unless you heat a plug or pull it . it oils up the plugs on kick starting . when i do get it going it puts out a lot of smoke, and when i stop it wont start . When i get it going it drives great. i just replaced the reeds please help its doing my head in. my mix is 40.1

  • @bailycoco - your premix at 40:1 is fine. If it is oily it can come from only two places. 1- oil in gas.  Since your ration is fine I would check your jetting. 2. transmission oil. This can leak into the crank from a bad right crank seal.

    You may want to check your pipe as well. I have seen many bikes (especially 125 and smaller) plug up with carbon and oil in the narrow part before the silencer (and in the silencer). Make sure that is clean and clear.

  • My 1994 KX 125 slowly leaks antifreeze from the overflow. I checked my manual, so i filled it with the correct amount. Any suggestions?

  • @ChiefDrakula

    I'm no expert but leaking antifreeze is caused by too much antifreeze being used or bike is overheating when running...

    Anti-freeze is nasty stuff so clean any up that your bike leaks...

    If the antifreeze leaks from around the engine then you have a blown gasket

  • @ChiefDrakula - many bikes will get hot and spit a little out. If it is getting below the cores in the radiator you may have a bad cap or a bad head gasket that is pressurizing the cooling system. If the bike is OK, we sell a Tusk high-pressure cap that works great.

  • i need to buy a flywheel puller from your site but dont no what size i need my bike is a 1999 yamaha yz 250 di you no what size i need

    thanks

  • @Yamahayz2502t - go to our site, enter your machine, and do a keyword search for "puller". You need a 27mm puller.

  • @RockyMountainATVMC thanks for the reply i will buy the 27mm

  • @RockyMountainATVMC thanks alot i will buy the 27mm from your site

  • hello the engine of my kx85 is making a much louder noise as normal but it still runs great.

    do you know if u just can take the bottom end apart and check all my bearings or should i first do something else?

    and how do you know when a bearing is full of wear?

  • i putt new water pump seals in my 88 cr 125. the hoses has presure in all of them and keeps blowing water out the piss hole on the bottom. u know why?

  • @mounts81 - Is it coming out the overflow or the small hole on the engine below the water pump. If it is coming out the small hole, the seal is still leaking. Could be an o-ring, shaft, or the new seal.

  • hi i have a question is the cylynder from the yamaha yz 250 02 same as th 05 model ?

  • hey i have a bolt that is really tight and the washer just gets chewed yup what do i do?

  • I have a question. Yesterday the shift lever broke off of my 2005 YZ250. It took the tip of the shift shaft with it. (appears to be the same bike you are working on in this video). At the same time I noticed a small amount of leakage around the shift shaft itself from the seal. Is it possible to replace the shift shaft and its outer seal by simply pulling the clutch basket and then the shift shaft and avoid splitting the cases? I guess I accidentally landed on the shifter instead of the peg.

  • @surlybonds71 - yes. you will have to pull the right case cover off, remove the clutch basket and then slide the shaft out. replace the seal before putting the new shaft in.

  • @RockyMountainATVMC - Thanks for your quick response, you guys are always so helpful! I went to go buy the parts from the site but I couldn't find the OEM fiches anymore. Did Rockymountain stop selling OEM parts?

  • @surlybonds71 - the OEM diagrams are down temporarily. We hope to be up soon.

  • helllo

    i want to know when should you do a bottom end rebuild

  • @Mr261194 - if you have any up and down freeplay in your main bearings or lower rod bearing.

  • I bought a tusk clutch holding tool of rmatv but can't get the center nut out, the nut is simply too tight and the more pressure I apply on my ratchet to undo the nut always just ends up with the inner basket slipping out of the holding tool, can you offer any help? I've got the engine out of the frame and clutch side crankcase off FYI

  • @sx512 nevermind I got it off, but F%## it was hard, I know it is torque to 80nm but with the engine out of the frame you need 8 arms to hold everything down :S.

  • @sx512 or fab a little stand with some scrap 2x4's and metal plate. clamp it to the bench.

  • how hard would this be to do by someone with all tools but with a average amount of engine knowledge and little expertise?? and are there manuals to do a engine rebuild, for a aprilia rx 50, cant seem to find any

  • @Krazer2100 - take your time and pay attention to how each part comes off. It is fairly easy. One step at a time. I do recommend a service manual if you can find one. The manufacture should have one.

  • i have a tm 125 and the primary gear just will not come off ive tried everything how can i get it off pleasee? :(

  • we let a man work on my dirt bike, and now he gave it back to us and its still in pieces, we know where everything goes exept one little piece, it looks like half a metal pill with a spring inside it, anyone have any idea what this is?

  • @mickieftw - It sounds like it could be a part on the shifting cam. they work like little ratchets to keep the cam in whatever gear you shift into. look at 6:42 in the video cloesly. Is that it?

  • what motor was being used for this demonstration?

  • @ed563 A YZ 250, you can see in the top end rebuild video, it's the same bike and you can see at one point a marking on the motor saying "249 cm^3"

  • @thisidnotinuse - correct. We used a 2004 YZ250.

  • couldnt you just use like cardboard or a rag for taking removing the primary drive gear?

  • The bolt was stuck on it but I got it off last night and got the new one put on

  • I have a 2003 Kawasaki kx 65 and the clutch went bad so I got a tusk clutch for rockymountain mc and went to take my other clutch off and it wont come off how do I get it off

  • @Bajabugman23 - I guess it depends why it won't come off. What is keeping it from coming off? Where are you having trouble?

  • Got a 1973 Honda CB750. New oil. Adjusted clutch. Grinds while downshifting from 4th to 3rd, 3rd to 2nd and most of all 2nd to 1st. Is this clutch or transmission?

  • hey just wondering if you could tell me what kind of bearing?, .bikee needs bearing on clutch basket shaft, iv looked around but i dont really know what im looking for, its a cr 125.

    thanks

  • Comment removed

  • @travisbest07 - the bearings have numbers stamped on the sides, these are roller bearings and can be found on ebay for about a dollar or so- the size you need is 25x29x22 hope this helps- keep wrenching

  • @chefoddity - all bearings are not created equal. I would get a good quality OE japanese bearing if you want it to last.

  • @RockyMountainATVMC -Oh I was just saying if he really needs one and can't find it, besides that is the size he needs. I have used conveyor needle bearings in the swing arms and haven't had a problem, but you are right a decent OEM japanese bearing is ideal.

  • Warpage lol

  • i have a 94 cr125 that sometimes when i shift out of 1st gear to 2nd the shift lever just locks up and won't budge but if i down shift and shift up again it shifts fine it does the same thing in the higher gear to is this something i should worry about

  • @troy118 - I would worry about it. I would start by removing the right case cover to look at the shifting mechanism. Maybe you will see the problem there. If not, it may be in the transmission.

  • One question: my shift lever stript out and it moves freely up and down with out shifting. I took the lever off and they both have threads but I'm not sure if I need to replace the gear shaft or the lever. How easy does the gear shift go bad or lose it's threads?

  • @Monsterenergy8771 - If you use a shifter that is loose, the splines end up wearing our quickly. The aluminum shift lever should wear out quicker than the steel shaft (assuming yours is aluminum). Inspect closely and replace what you need to. Make sure to watch the lever and keep it tight!

  • @james99rm125 Thats what i use

  • This is a pretty lame method but if you want to remove the flywheel nut just stuff rope down the spark plug hole. When the pistons reaches the top everything will stop and you can break the nut free. Been doing it on all my bikes never had any problems.

  • @james99rm125 - Great idea!

  • @EvansAutoShop - Try our website!

  • Man..rebuilding my 1991 CR250 was way easier than this. Lots of parts!

  • i was a moron and did not use a impact screwdriver on the stator screws and they stripped how can i get them out?

  • @cantbuyrespect - have you tried an impact since you stripped them?

  • when i was taking out my clutch bolt holding the assembly(the bolt in the middle) i heard a loud popping noise and now the clutch just spins with no resistance to it at all what could this be?

  • @15tbizzle - The inner hub is tied directly to the transmission. Did it pop out of gear? i would inspect.

  • why do you need the clutch holder and flywheel puller? seems like they do that same thing?

  • @OPureGHOST - they are both very different. You can hold a flywheel with the clutch holder tool, but it won't remove the flywheel - you need both tools working together. On the clutch, the flywheel puller won't do you any good.

  • i had a bolt brake off in my clutch basket how would i be able to get that out???

  • @15tbizzle - It you can't work it out, you will need to drill the bolt carefully (centered) and use and easy-out bolt remover.

  • What do i do if i only want to take the side casing off because the oil check is stripped out, can i just take one casing off then the next? or do i have to take off the top and fallow the steps to get to it on the video?

  • @LVRidaZ - The right case cover will come off, but the two center cases won't come off until you remove the cylinder and pull the motor from the frame.

  • Hello

    I have a husqvarna 125cc. Are the special tools used in the video (case splitter tool and the crank puller) good for it?

    Thanks for answer

    Merry X-mas

  • @Luzak47 - I can't say i have been in a Husky 125, but they should be fine.

  • @RockyMountainATVMC

    ok thank you. I think it will be fine for my husqy.

    With greethings

    Dawid

  • is this the same for a atv

  • @01161996bubba - yes. of course this varies on each machine. Refer to your manual for differences.

  • go @rmstator.com the ave all the answer 

  • could you plz answer me back PLZ I NEED HELP... My ds 650 starts very well and idles extremely well! But when i go riding about 25 secounds of riding it she stalls whit a screaming noise... so what im thinking since de 2000ds 650 model haves bushing and not bearings in the connecting rod so when the bike gets hot the bushing sticks on the crank and makes that loud noise and sudenly stalls...thats what im thinking does this make sence? PLZ HELP ME

  • @rickyelementsk8er - It makes sense, but the only way to know is by pulling it apart. I would be concerned about the oil pump if this is the case.

  • @rickyelementsk8er hey dud go to rmstator .com the will help you

  • @dudfreek thank you but the problem is not beacus of the cdi box but thanks for your concern

  • Hi, this a yz 125 or 250 motor you're working on here?

    I must say your videos are very informative to watch.

    Our local suppliers dont really carried much when it come to service manual and tools, so i'm having to use the web to get most of my info.

    '03 yz125 that i have to replace the crank as the bearing on the conrod packed up.

    I see i can order most of the tusk tools online, not sure about the Tusk Flywheel Puller. Any idea of the size i must order for the bike? 24mm and 27mm option.

  • @jacquestdi - this is a YZ250. You need the 27mm puller for your YZ125 (same as the 250 and most other 2-strokes). good luck.

  • can u guys do a video on the names of the parts of the motor and trans and what they do...thanks...yamaha rocks...

  • why does the ignition side have a reverse thread i thort it only need a reverse thread on clutch side?

  • @chrisross2343 - The only thing reversed on this bike is the threads for the flywheel puller. What are you refering to?

  • @RockyMountainATVMC oh i see, my ktm has a reverse thread on the clutch side, i thort the flywheel puller worked off the crank.

  • hi i have a question,I was riding the other day and for some reason It would not let me change gears sometimes, and i am not getting enough power out of it, what i mean by that is when the revs start to get high they go back down even when im almost full throttle, can you help me please. thanx

  • Thank you!

    

  • atv repair

  • I have a question my bike pops out of gear in the every gear but first. will i need to split the case to fix it

  • @fatwhiteboy77 - most likely, yes. you probably have bent shift forks and wore gear cogs.

  • do u knoe what the price this would be too have somebody do that for u and what new parts you'll need

  • how long should you wait to rebuild your bottom end because some people say 2 top ends to 1 bottom end

  • your my idol, i wanna be a motorhead when im older

  • You should use a penny instead of the aluminum washer - not only is it cheaper, but copper is also a softer metal :)

  • @memphetic - if you actually have a penny made of 100% copper (made from 1793 to 1857), I wouldn't ruin it. It is most likely worth a lot more than 1 cent. If you have a penny older than 1982 it will most likely have a decent ammount of copper in it. 1982 and newer are 97.5% Zinc with copper plating. The aluminum washer works great!

  • @RockyMountainATVMC Zinc is even softer than copper! :-P And still cheaper :) But as odd as it seems, washers do seem more plentiful than pennies.

  • @memphetic - Good call! maybe just avoid the 1943 steel penny and you will be fine.

  • @RockyMountainATVMC Ahhh there's always a wrench in the works :-D

  • @RockyMountainATVMC Hey I was wondering if the crank install tool would work on my 1994 KX250, because mine has the snap ring. Also, if it wont work, how could I pull my crank into the bearing?

  • @BigManlyMan4 - great question. Two ways to do it. 1. wait for the snap ring adaptor we are going to stock - I have one in production now that is specific for the KX250. It won't be done until mid september. 2. heat the right case half to 200 degrees in an oven (flame will ruin the seal). Freeze the crank shaft. It will drop right into the warm crank bearing. Then assemble the tranny on the right side. Use the tool to pull the left side together.

  • @RockyMountainATVMC do I have to use the crank install tool to install crank to the left side? or does it just slip through the bearing? I would rather not buy the tool until that adapter comes out.

  • @BigManlyMan4 - Yes, you will need it tp pull the crank into the bearing.

  • is the shift shaft suppose to slide in and out smoothly when u take it out?? if it doesnt does it mean its time for a new one??

  • @paintballer2X5 - the ones I have seen do. If you doesn't, you need to figure out where it is binding before you buy a new one.

  • hi there, would you be able to make a vid on how to split and rebuild a crank. cheers

  • Why do you have to heat the case and freez the bearings. What if you didnt do that??? Thanks

  • Freezing the bearing slightly shrinks the metal and heating up the case slightly expants the material. It makes it easier to get the bearing in. Same with wheel bearing on cars etc.

  • Hi there i have a scratch in my crank case where the crank sits, does this need to be treated, even though it ran like it before (dont know how well as i baught it 2nd hand).

  • Could you list the tools you used i'm planning a disassembly myself, thanks.

  • where are you located i need my crankshaft and piston replaced and wateva else is necessary you are real good wit your work! i would love fo you to do my bike anytime!

  • @money050 - We are in Utah.

  • Thank's Eric!!! So stoked about this. I recently burned up my clutch and needs replacement. I was thinking about a pro mechanic but they're so expensive that Id rather take a chance on doin it myself. But im very mechanically inclined otherwise a mechanic would be the correct choice. So, Thanks again for all your hard work and showing us this great videos!!

  • @RicNetro17 - thanks! Glad you like them.

  • on my 01 yz125 every time i start it i hear a kinda grinding or tinging sound from the crank area so i was wondering what this might be, at first i thought it was the head gasket and piston rings ,but its not do i need my bottom end rebuilt?

  • @nickemery41 make a video of the bike running.

  • @02hondacr125 - why exactly?

  • @RockyMountainATVMC its easier to tell whats wrong with nickemery41's bike.Which its probaly just his powervalves. And nice video very helpful on my rebuild.

  • I have found (after many bottom end rebuilds) that instead of a hand held impact screwdriver, the better tool to use is a Craftsman Impact Driver. They are 19.2 volt cordless, and it has a quick connect bit attachment. I am a Sea-Doo mechanic (and do pretty much any 2 stroke wrenching on the side) and have found it to be invaluable.

  • lol i dont have any of those tools i made all my own out of steel bolts and a torch haha

  • i just bought the tusk flywheel puller and i started trying it and it feels like i need alot more strength for it to loosen but i'm afraid that if i push it down more it will break.

  • @JoelPotter1 - the flywheel is "wedged" onto the crankshaft. It takes a bit of force to pop it loose.

  • my bike is stuck in 1st or 2nd gear i cant put it in nuetral and i cant kick start it anymore??? you think you can tell me whats wrong. i have a yz250

  • @paintballer2X5 - i can tell you that you need to pull it apart to find the problem. obviously something wrong with either the gears, shift forks, shift cam, or all of them.

  • how do you remember what parts go where. like bolts and everything do organize it or what??

    thanks

  • @crf250rider6 - I organize.

  • would the tusk fly wheel puller work on a 97 kx 125?

  • @jriemer43 - yes sir

  • well yea

  • @jriemer43 - yes

  • i have a 1996 yz 250 it needs a crankshaft what years will fit it????

  • @james420slc - I don't know. you would need to check part #'s on a parts diagram.

  • gone to use my TUSK ! keyboard to comment lol nice video

  • ok so i no this question may sound dumb but what does a flywheel do

  • @skoolsuckz12 - primarily carries the magnets to allow your coil to produce spark/power.

  • it makes the front tire fly up in the air its like the powerband thats why they say 2 strokes r easy to catwalk

  • @wolfgang29 - say what?

  • it was a joke for the dum question about the fly wheel

  • really great video !

    At home i have a workshop, all the tools, but i can't find a repair manual for my 2007 ktm sx 125! I have looked on internet ( stores, ebay...) but nothing! Can anyone help me to get to this manul?

    If I would found one for 2006 or 2008, would it be able to do the job ( I mean, are they similar to 2007, if it does exist ) !? Please help

  • This video will be a great complement to my English classes. Thank you.

  • i have a 2002 yamaha blaster 2 stroke. when i bought it, the dude said it needed clutch plates and pressure plates. i took the crank case off n discovered that all the plates were in great shape. when i go to kick start it, the kickstart dosent retract to the up right position. the spring on the inside of the crank case is just kinda flopping around. i was wondering where it clicks into so it can retract. thanks for all your time and help

  • really i like this video. it make me more know about it. so thank's alot. can i download it? how? thanks

  • @nanangernawan - It is just available on youtube.

  • iv got a kawasaki kdx 220 2stroke 2001 and i cant put the crankshaft into the right hand side housing downs anyone have any tips

  • @rockmusicismyidol - Kawis are tricky because they don't have a bolt or nut on the right side, making it hard to use a crank puller. The best way to do a KX, or KDX is to heat the right case half in an oven to about 200 F (this is about where water boils and it won't damage your seals). Freeze the crank. Once the crank is froze and the case (and main bearing in the case) is hot, the crank will drop right in. Assemble the transmission on the right. then use a pulling to install the left side

  • hey man i have a question i have a 1986 yz125 and i wana take it apart to reoplace the crank bearings what tools would you recommend so that i could remove the fly wheel?

  • how do you get off the center bolt off the clutch, its really tight

  • @bikercc - i think we show that in the video. Do you have a clutch hub holder tool. if that won't do it, use a pneumatic air impact.

  • i mean my outer cover housing the pump and gears and whatnot, not my clutch cover *fixed*

  • I would change the water pump seal. That is the most liekly problem.

  • @dudemanthing919191

    Dont the bike have a weep hole? should be a small hole at the bottom of the engine casing by the water pump, if no anyway replace the water pump seal & oil seal!

  • yeah i checked the pump seal, put water through it, and its not leaked a drop yet, the gasket linning the clutch case and crankcase was pretty banged up, even around the water flow hole, got a new gasket commin soon, so ill see what happpens....its it really that bad that coolant is leaking into the trans, and clutch tho?

  • It certainly isn't good to have water in there.

  • thanks rockymountain atvmc, for the videos, to think i went to school for all this when i could have just seen the videos, lol, good, salesmanship. by the way are ya hiring? fresh M.M.I grad. just lot older grad. 45, responsible,hardworker willing to learn even more

  • @vinnyvalenz - thanks for your comments. Sorry, but we aren't hiring now. Good luck with your new career choice!

  • hi, i got a 1992 YZ 250 2 stroke, it leaks coolant form the radiator into the the clutch area and turns the gear oil into a graish white color, the flywheel on the other side is dry though,what would i want to look for if i take off my clutch cover? or do i need to split the entire motor apart, thanks!

  • hi there, my 125 aprilia rx motocross has the following problem, it smokes like crazy most of the time and stutters now and again like its choking on oil in the bottom to mid range of the revs, it however still pulls like a train and smokes a fair bit less when i am at full throttle at high speed, the engine hasnt done that many miles even though the bike is 14 years old, what would you say the problem is? im guessing crank seals or a over the top adjusted autolube system? cheers in advance.

  • It could be a few things. 1 - leaky right crank seal. 2 - too much premix in gas or injector is dumping too much in (if you have an injector) 3 - poor jetting - very rich fuel mixture.

    All 2-strokes smoke some what. Keep a close eye on the color of your spark plug.

  • by any chance can the seal on the stator side of the crank come loose and cause a leak?

    KTM 360sx

  • I doubt it would come loose, but it could definitely wear out and leak.

  • may i ask why you are using a impact driver when the screws are showing no form of damage or rust?

  • With philips head screws - using and impact driver prevents damaging the heads.

  • wow....very comlicated....i will never try to do these stuff alone on my bike :-/...

  • It is actually quite easy. I am sure anyone could handle it.

  • also i forgot to mention that the cylinder is off and a block of would with a slot cut into it is inbetween the piston and case. so the that the clutch basket wont go anywhere.

  • use an impact if you have one. It will buzz off.

  • i know that the nut is counterclockwise. Im trying to get the nut on the clutch hub loose. I have the tusk clutch hub holder and had it braced up against the foot peg mount and it aint goin no where, im just worried about damaging the hub. I had so much pressure on this thing trying to get it loose. Im thinking about putting alot of rags in between the clutch basket and hub then using an impact wrench to get the nut loose. You got any ideas???

  • about how much would it cost to rebuild a 2 stroke 125 dirt bike?

  • i would probably end up scrappin the bike if i ever had to do this lol. kick ass videos though.

  • if the piston rod wobbles side to side, do i need to get new bottom end bearings? my buddy says its fine, but i think this wobble is the reason my piston and jug are scared...

  • side to side is most likely normal. up and down movement means the bearings are shot.

  • ok good!! haha this looks complicated and expencive ahah

  • Umm I think I need to order a puller from you guys then, I have a 2000 RM250 do you have a puller that would work for both my RM250 and my wifes 93 RM125 That crankshaft puller /assembler you used will that work for both bikes aswell

  • Part # 1179010002 will fit both bikes and most other two-strokes. You don't need any special tool to put it on. just tighten the nut.

  • I have my top end off and when I spin the crank by hand with the rod I feel it tighten then loosen about 6 times per rotation ?Am I feeling the magnets in the magneto or a flat roller bearing?The crank has no play when I try and lift up and down on the fltwheel Just hoping I dont need to split the cases!

  • It is hard to say. Unless you have unhooked your primary gear on the right side your crank is still driving the clutch and water pump. It could be resistance from those as well. remove the primary gear on the right side of the crank to be sure.

  • I will do that to help isolate the resistance Im still wondering if the magneto magnets cause risistance?The bike is a 1993 RM 125 The risistance is smooth and not the binding kind.Its wierd and bugging me.Thanks alot for all your videos and timely rsponses Thanks Jay

  • i suggest pulling the magneto to eliminate that factor as well.

  • Great answer! Its just I dont have a puller!Have you ever felt resistance from a magneto?I have an old YZ490 with the jug off and it has no resistance at all but its a 1982.

  • hey i have a 02 yz 125 when i push the bike in nuetrle in jams up i push it back a bit and will go foward but it jams up goin backward aswell. have u any idea wat this is? thanks

  • I am not sure what you mean, but if it is in neutral and the transmission binds when yu push the bike, it sounds like you have some serious problems with eithes some transmission gears of shift forks. You may want to disassemble and inspect.

  • hey, i have a 05 yz 125 and i recently blew something, as i was riding it cut out and i heard a crunching noise like metal on metal. It still has good compression but when i push the kick starter through i hear a clicking noise at the same spot every time. Any ideas what it could be? thanks

  • u probably blew it up, take ur jug off and check ur cylinderfor deep scratches, ur rings could have done alot of that damage, the same thing happened to my 80 when i bought it, the cheapest way 2 fix it is take fine sand paper 2 ur cylinder (until smooth) and buy new piston and rings

  • You certainly need to remove the cylinder and check the damage.