KTM 125SX MOTOR REBUILD

KTM 125SX MOTOR REBUILD | Part 1

Рет қаралды 36,429

3 жыл бұрын

We finally start the KTM 125Sx Motor Rebuild. Part 1 we install the bearings, crank, transmission, shift assembly, and mate the case halves. I'm loving how this engine is looking and can't wait to see the final product!
Thanks for watching, if you enjoyed the video give it a like and please subscribe to the channel! Share it with your friends and we will see you in the next one!!!
---Must have Reading Material!!---
The Four Stroke Dirt Bike Engine Building Handbook: amzn.to/2Y7NvL5
The Two Stroke Dirt Bike Engine Building Handbook: amzn.to/39QlE4e
⬇️ As always the links to the tools, parts, and equipment I use are listed below! ⬇️
-----Engine Rebuild Tools-----
∙Milwaukee 3/8-in Cordless Ratchet: amzn.to/3vqYX0c
∙Milwaukee FUEL Stubby 3/8 in. Impact: amzn.to/3BWaJSY
∙T-Handle Wrench Set: amzn.to/3roqtK2
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∙Propane Torch Bottle: amzn.to/3kJtSSq
∙Torque Wrench 1/4" Drive Inch/Lb: amzn.to/3iCKs3o
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∙Maxima Assembly Lube: amzn.to/3kHssrj
∙Maxima Contact Cleaner: amzn.to/36SfXBq
∙Maxima Waterproof Grease: amzn.to/3zro7wK
∙2 Stroke Premix: amzn.to/3kLJeWm
∙Flywheel Holding Tool: amzn.to/3ziHAQz
-----GoPro Mount-----
∙Dango Design Gripper Mount: amzn.to/36ytQEk
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∙Canon EF-M 11-22mm f/4-5.6 STM Lens: amzn.to/3wtirQN
*Disclaimer - As an Amazon Associate I earn from qualifying purchases.*
-----Join me on Social Media-----
Instagram: / danmx2112
#danmx 2strokebottomend #ktm125sxenginerebuild

Пікірлер: 103

@braydenruttley1184 2 жыл бұрын

This channel honestly deserves more than 900 subs. Your videos are incredible. Keep up the good work and I hope your rebuild videos reach more than 300 odd views.

@DanMX2112 2 жыл бұрын

Dude, that means more than you know man! Thanks so much for the kind words, it’s a grind and sometimes hard to stay motivated. I’m pumped you feel this way and please, share the videos, it helps so much! Thanks Brayden, and thanks for subscribing!

@Monaro400 Ай бұрын

Dude, your videos have been a massive help with my sons KTM125 build. Fully appreciate the time you have put in to make this content. It's definitely the best I have found. Cheers

@DanMX2112 Ай бұрын

Thank you sir, I really appreciate it. I’m glad they helped and I hope your boys bike rips!

@Thermostatti 2 жыл бұрын

Thanks

@daveywinn8513 2 жыл бұрын

Can't thank you enough for these videos massive help with my build

@DanMX2112 2 жыл бұрын

Thanks brother, glad they help! good luck with your build!

@cbadnc9040 3 жыл бұрын

Great video! Very detailed with great explanations! Thanks for not adding crappy music!!

@DanMX2112 3 жыл бұрын

Thanks dude, I’m always trying to do better, that’s the goal!!!

@marcomonte99 Жыл бұрын

Awesome video, incredibly detailed explanation, continue like that, personally I’ve saved every single video accorto this ktm engine rebuild to watch in offline like a video manual, this channel is the best

@DanMX2112 Жыл бұрын

Thanks Marco, the goal is to help guide others to success! I’ll keep the details and long form to help with every aspect!

@mascalzone81 Жыл бұрын

hi, could you show me the site where you see the spare parts exploded views, from the video you can't see the name of the site on your phone, thanks

@DanMX2112 Жыл бұрын

rockymountainatvmc.com

@obi6304 3 жыл бұрын

Awesome clip! Waiting for part 2 since i'm rebuilding the same engine

@DanMX2112 3 жыл бұрын

Thanks dude, I’m working on it as we speak! Should be up this week!

@freetaylor72 Жыл бұрын

This is the most informative videos on ktm motor builds I've found on the older model 2 strokes. Now I'm finding it hard to find the rebuild kit... there's one for the 2000 to 2002 EXC, but will that be the same? Surely cause this 125 sx looks like my 200. If I have to split the cases to fix 1 crank bearing, then I should just rebuild the whole dam thing. Anyways thanks for taking the time to make these videos man!

@DanMX2112 Жыл бұрын

Your welcome brother and thanks for the kind comments. I would replace the crank bearings as a set and whatever else feels it may have some catch, or rough feeling when rotating. Trans bearings usually are not issues at all, but it’s kinda one of those deals. Do it while you in there.

@stephenormsby3662 8 ай бұрын

Excellent video, very helpful. Thanks for posting!

@DanMX2112 8 ай бұрын

Thank you sir, glad you enjoyed!

@jmcpacheco 3 жыл бұрын

Nice videos.. keep them coming. :)

@DanMX2112 3 жыл бұрын

Thanks dude, I am loving the build process!

@2strokemadness9 2 жыл бұрын

Left hand crank bearing is a dick on removal 😁 I had to remove the roller bearings and place a large washer behind it because it's blind

@DanMX2112 2 жыл бұрын

I used a punch after heating the case, worked like a charm. But, I agree those roller bearings suck compared to the ball bearings! Thanks for watching man!!!

@2strokemadness9 2 жыл бұрын

No problem you did a nice job I got my rebuild on my channel same one you did lol good engine tbf

@Moerk-vn4zq 3 жыл бұрын

Hi, great videos. Can you tell me the part number of the ignition cap you used? It seems that the cap is from a newer model. Thanks!

@DanMX2112 3 жыл бұрын

Sure! It’s 50330002400 off of RMATVMC. It’s an updated version as they no longer make the magnesium covers anymore. Looks sick!!!

@Dylan-zv3gs 2 жыл бұрын

Hey man, did you have to order the small black bearing at 6:09 separately? Doing the same rebuild, got the bottom end kit but it seems to be missing that bearing.

@DanMX2112 2 жыл бұрын

I don’t remember to be honest. But it should be very cheap to order as it’s such a small bearing. I wanna say it came in the kit, but can’t remember.

@skylercomer1291 3 жыл бұрын

Awesome videos, very helpful, so when sealing the cases you don't use any sealant? Just grease and the gasket, What kind of grease are you using?

@DanMX2112 3 жыл бұрын

Correct, I don’t use sealant on the KTM, it doesn’t call for it. I use Maxima waterproof grease, and I put a link in the description below ⬇️ go check it out.

@skylercomer1291 3 жыл бұрын

Cool thank you. This channel is gonna blow up sooner or later

@DanMX2112 3 жыл бұрын

Dude thanks so much, it’s because of guys like you commenting and helping out that make it work! Please share it brother and thanks for watching!!!!

@joshknight129 2 жыл бұрын

I’m doing a rebuild on this same engine and I was wondering if the counter shaft bearing sticks out from the case slightly or if it is supposed to be in set slightly like the crank bearings.

@DanMX2112 2 жыл бұрын

Yes it does just ever so slightly, on the inside that is. Just make sure the bearing seats and you can’t go wrong! Thanks for watching

@joshknight129 2 жыл бұрын

@@DanMX2112 awesome! Thanks for the quick response! Great videos 👍🏼

@johnharding9936 2 жыл бұрын

Hi Dan, I'm getting lined up to do this to a 250, which is a very similar motor it seems. Maybe you mention it, but, did you use a wrench rabbit kit here or did you source the parts OEM. The all in a box solution seems like a good option but I hear mixed reports so I don't know which way to go. Thanks.

@DanMX2112 2 жыл бұрын

I’ve never had an issue with a wrench rabbit kit. The kit came with the bike when I bought it, and it was a Wiseco crank. I went with OEM bearings and ran a Namura piston.

@johnharding9936 2 жыл бұрын

@@DanMX2112 Okay, thanks for the reply.

@markalan4026 2 жыл бұрын

Is there supposed to be a gasket between the engine block and reed cage? What about between the Reed cage and intake Manifold flange?

@DanMX2112 2 жыл бұрын

If you notice in the video, there is a gasket between the reed cage and cylinder, but nothing between the cage and the intake boot. Hope that clears it for ya.Thanks for watching Mark!

@markalan4026 2 жыл бұрын

@@DanMX2112 Yep, I did infact notice what appeared to be a green gasket. Here's the thing, I looked at several parts diagrams online for a 2003 125 sx, some showed a gasket, and others did not. For all I knew, you just cut one yourself for peace of mind. In the process of chasing down a lean condition right now. I pulled the intake flange/reed cage assembly off, there was no gasket installed in either of the locations I asked about. Even though it went against my better judgment, I thought perhaps engineers didn't find a gasket necessary between the engine cases and reed cage, since the cage itself has the rubber coating. I did put a gasket there, and coated it on both sides with a super thin layer of ultra black rtv, using the dab method to apply it. I did this between the cage and manifold flange as well. I'm really hoping this fixes the issue, it's been a bit frustrating sorting this out.

@DanMX2112 2 жыл бұрын

If it’s a true lean issue and your jetting is good, you may have some bad crank seals. I’ve seen many bikes with the rtv in between the boot and reeds, it’s not really an issue. It becomes an issue when you loose the rtv pieces into the bottom end and tear up the crank. Sounds like you making progress, just be very mindful of rtv as it’s not a fix, but a bandaid!

@markalan4026 2 жыл бұрын

@@DanMX2112The jetting seems to be spot on according to KTM recommendations, and if anything, a bit more on the richer side of things. If this fixes the issue, I will then order a new 70 dollar manifold flange. I definitely do not like half assing things, but I also don't want to start dumping unnecessary money into this 20 year old bike either. Before tearing into it, I did use brake clean trying to pin point the leak while the engine was idling. The results I got were iffy, but I wasn't necessarily expecting a strong reaction to begin with, since the lean condition was only present at high rpm. If this fixes the problem, I will let you know tomorrow. Thanks for the replies!

@markalan4026 2 жыл бұрын

@@DanMX2112 That was the problem. Just took it out for a ride, and the bike absolutely rips now.

@mathiasm91 2 жыл бұрын

Hey man. Where did you get that ignition cover? Clean engine. tia

@DanMX2112 2 жыл бұрын

It’s the OEM replacement from KTM, they don’t make the magnesium cover anymore. Just look it up on RMATVMC. Thanks for watching!

@rider4life90 9 ай бұрын

Hello Boss!its normal to crankshaft have some axial play?nice video!thanks!

@DanMX2112 9 ай бұрын

Yes, just a little, but I’m not sure how much. All cranks have to have some Axial play, or you would destroy the main bearings.

@rider4life90 9 ай бұрын

@@DanMX2112 thanks!

@scottdavis9458 8 ай бұрын

Approximately how hot did you have to get the inner race of the roller bearing before it would drop down onto the crankshaft?

@DanMX2112 8 ай бұрын

Not sure, I’ve done many engines sweating bearings and I just kinda know when enough is enough. About 300-350 degrees should be fine to sweat bearings.

@felixstrandborg8580 4 ай бұрын

Hello again, thank you so much for all the videos and anwsers but do you know how much clearance there can be in the connecting rod bearing? I have about 0,6-0,65 millimeters and I think it’s to much? Thank you!

@DanMX2112 4 ай бұрын

Axial Play (left to right) around .025mm-.040mm. Up and down or radial should be nothing, snug as a bug.

@felixstrandborg8580 4 ай бұрын

@@DanMX2112 Thank you for anwsering but are u sure it is 0,025 mm - 0,040 mm? I have 0,60-0,65 mm side to side and thats a huge differenc

@felixstrandborg8580 5 ай бұрын

Hello, does it matter which way the bearings with plastic in the gear box is facing?

@DanMX2112 5 ай бұрын

My opinion is no, some may say different, but I would bet it gets lubricated just fine.

@Bikes_andmore Жыл бұрын

I did the case bolts on my bike I just took one bolt out and put a new one in and just did them snug up by hand should it be alright? Its been about a month and it’s not leaking or anything

@DanMX2112 Жыл бұрын

Honestly, if it hasn’t leak, it’s tight enough. I would still go back with a torque wrench and just hit them to 7 foot pounds and just make sure your dialed.

@andrewocel6256 2 жыл бұрын

Did you cerakote the engine cases?

@DanMX2112 2 жыл бұрын

Only the clutch side case cover and the outer clutch cover. The inner case halves are the original anodized color. Turned out sick!!!

@simeoneuropaeus727 4 ай бұрын

Hi, I don’t have that rubber thing in my engine (28:15) or it’s missing. What will happen, if that thing is missing? Thanks and greets from Finland.

@DanMX2112 4 ай бұрын

You need it, it’s a separator for the oil, keeps it where it should be when running.

@karl-sander8426 11 ай бұрын

25:40 It looks like those gearshafts are missing one gear each between the two gears closest to the ignition side. Am I blind or is the bike really fivegeared?

@DanMX2112 11 ай бұрын

It’s a 5 speed, you are correct ✅

@lilJ5754 2 жыл бұрын

What year is this motor? Are all ktm 125sx motors identical/similar? I'm looking into a rebuild for my 03 125sx!!

@DanMX2112 2 жыл бұрын

Hey man, first of thanks for watching! And yes, yours and mine (04) are basically identical. So follow my build series and you should have no issues getting it rebuilt. I suggest downloading a manual online, just for specs. Idk where I found mine, but you can get on thumpertalk and find one I’m sure! 🤙

@lilJ5754 2 жыл бұрын

@@DanMX2112 Awesome!! I'm pumped. Engine work always sounds so hard and scary but it isn't too bad by the looks of it!! Keep it up and I'll be going through this series many more times 😁😆

@DanMX2112 2 жыл бұрын

Haha right on man, and reach out with any questions!!!

@danielkarlsson608 2 жыл бұрын

Sorry for commenting on such an old video, but I just found your channel. Great build series. However, I have a concern about the main bearings inner race that you heated up before slipping it on there. I´ve seen a lot of SKF mounting instructions for bearings, and they recommend heating to 90-110 degrees C, around the boiling point of water. 212 degrees F. To make it brown on the surface it has to reach around 250-260 degrees C. Which is around 500 F. At 295 C it turns blue. This amount of heat may affect the hardness of the bearing race. I hope it was OK, but I think you went a bit too far.

@DanMX2112 2 жыл бұрын

This is awesome info, and I really appreciate it. So the funny thing is I thought that I heated it up to much, but I checked it with my temp gun before hand and was around 300 F. What turned it brown was the WD-40 that I sprayed on it before I stored the part. Trust me, I was very worried. And I’m grateful for your insight and specific temps. So if I understand correctly, is over 500 F where I’m going to affect the hardness, or before that even. Wanting to know more of this.

@danielkarlsson608 2 жыл бұрын

@@DanMX2112 I would not go over 240 degrees F. For normal mounting of any bearing parts. At what specific temp damage occurs is information that is hard to find. Generally the information is given regarding a complete bearing where there often is a plastic retainer, rubber seal, grease, and so on. Also the expansion coefficient is at this point great enough to mount the bearing even without cooling the other part. In your case the inner race was by itself, so I hope nothing was affected. For a normal workshop (without bearing induction heating equipment) I would recommend a hot plate, a temp gun, and a drop of water to determine if it is hot enough. When a drop of water boils, you can mount it. On a hot plate you can let any sort of bearing reach 240F safely.

@DanMX2112 2 жыл бұрын

I’m sold on the hot plate idea, I think for the next build I’ll put my cases on a hot plate and allow the heat transfer to happen controlled. With the expansion of aluminum being greater than steel at the same temp, this will ensure no mistakes and weakened metal. Given that most of the install is a bearing into a housing, than freezing and Inserting into a hot case is the majority of the work. This is an awesome thing that you reached out, and have given me some ideas. What’s your take on case halve heating, hot plate or oven?

@danielkarlsson608 2 жыл бұрын

@@DanMX2112 any will work. For larger cases, an oven would be ideal. If you only get the hot plate, it will work as well.

@DanMX2112 2 жыл бұрын

Love it, thanks Daniel!!!

@DrMonkfish2010 2 жыл бұрын

Hi, i have a 07 aswell and i just rebuilt it aswell but somehow it takes a lot of force to shift. I dont know what ive done wrong or if its a problem with transmission or the shift mechanism because it shifts in every gear. What if noticed is the shiftdrum was really hard once i put the cases together…

@DrMonkfish2010 2 жыл бұрын

Shiftdrum was hard to turn*

@DanMX2112 2 жыл бұрын

Sounds like it’s bound up for some reason, maybe a bearing clearance issue, not seated?

@DrMonkfish2010 2 жыл бұрын

@@DanMX2112 thanks for answering, ill split once again...

@DanMX2112 2 жыл бұрын

Idk what else it could be?

@DrMonkfish2010 2 жыл бұрын

Well, its weird coz when i put in the main and countershaft with the shiftdrum it worked properly, once i put the other casehalf on and tried to turn it was like really hard to turn, could only turn it with ratchet, should be able to turn by hand no? And also i made all bearings new so im so confused.

@arturfigueiredo3414 Жыл бұрын

Hi who match cost to rebuild ktm125 sx engine

@DanMX2112 Жыл бұрын

Depends on many factors, a top end can cost as little as $100, to $1500 for a full Motor.

@alanporter2769 Жыл бұрын

Did you use the wiseco crank

@DanMX2112 Жыл бұрын

I did, and the bike has 5 hours on it currently, wide open packing my 220 butt around lol

@alanporter2769 Жыл бұрын

@@DanMX2112 haha it definitely is a really fun bike and your channel deserves so much more love it's honestly hard to believe the lack of views and subscribers you have you'll get there one day

@DanMX2112 Жыл бұрын

@@alanporter2769 thanks man, it’s a long game for sure but it will be there soon! Gotta keep grindin!

@alanporter2769 Жыл бұрын

@@DanMX2112 for sure !

@tonnon64 3 ай бұрын

Hello I have a problem when I tighten the crankcase screws with the torque the crankshaft doesn't turn what can it be?( All the pieces are new)

@dailyshreding9393 3 ай бұрын

hit either one of the sides and it should loosen up

@tonnon64 3 ай бұрын

@@dailyshreding9393 It worked, thank you

@DanMX2112 3 ай бұрын

Sorry missed your comment, but @dailyshreding9393 was right. Sometimes the crank can somewhat bind with the bearings in install, and this can usually be freed up by just shocking it.

@DanMX2112 3 ай бұрын

Perfect!