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Motorcycle Bottom End Rebuild | Part 3 of 3: Final Assembly

Motorcycle Bottom End Rebuild | Part 3 of 3: Final Assembly


This is Part 3 of the split cases, crank and crank bearing replacement video. Please refer to Parts 1 and 2 for the previous
procedures In Part 2 we installed the crank into
the right case half, and now we’re going to install the transmission. And it’s important to try do this as an
assembly, with your shift forks installed. Everything lined up. And we actually made this look easier
than it is, it actually can be kinda tricky. You want to make sure that everything rotates smoothly. You can tell that the gears are lined up
where they need to be. It won’t be possible to shift through the gears at this point until the other case half is on. But you should be able to tell that
everything is lined up. Now we’re going to get ready to install the other case half. And some machines have gaskets, other machines just require a liquid gasket. Here we’re using Yamabond Make sure your sealing surface is very clean before you start. Make sure you put sealant on both halves. Now we’re gonna go ahead and slide that
on and be really careful and make sure everything is lined up correctly Before you start pulling the crank
through. Make sure all the shafts are starting to fall into the bearings. You want to make sure the cases are parallel. We’re going to go ahead and install our crank puller/ installer back onto the crankshaft. Use the right pieces. Put the outer piece on. Thread the nut on. And as we tighten this, once again we want to make sure everything is parallel and the case halves are coming together. We’re going to make sure they’re parallel. We might need to
take a rubber mallet and tap the back. Just to make sure everything comes together nice and even. Now we can go ahead and put our bolts in. Here we’re just
illustrating how to tell if your bolt is the right length or not. As you put them in they should all stick out about the same before you tighten them. We’re going to go ahead and tighten them now and we’re going to use a criss cross pattern. To make sure there’s no warpage. You don’t want to develop a leak between your center cases. We’re working on the other side of the
case. We’re going to start installing our shift mechanism. We’ve put a little medium strength threadlocker on our star shift detent. Now we’re going to go to our, make sure our shift pawls are in there. The springs are all together. We want to install that as an assembly. Now we’re going to slide our shift shaft through. Make sure everything lines up. This is our kick-start idler gear. There’s a little washer on there, then we’re going to use our Tusk Circlip Pliers to install that circlip. We’re just going to use a screwdriver to seat that clip in the groove and then I’m going to move to the primary drive gear. There’s normally a spacer. Normally there’s multiple gears to either drive the water pump or power valve. Slide those on. Now we’re going to move on and put the outer clutch basket on. It’s our washer, our sleeve and our double bearing. We’re going to put our inner hub on. With our lock washer. And the nut. We’re going to use our Tusk Clutch Hub Holding Tool. And go ahead and torque our clutch hub on. Now we’re gonna bend up our lock washer. Now we’re gonna wedge our aluminum
washer back in there. So we can tighten up that primary gear. Don’t forget to remove the washer. Now it’s time for the inner clutch cover. Make sure everything lines up. There’s a water pump that needs to lineup on a gear. Sometimes you need to move things back and forth a little bit to get it to lineup correctly. We’re going to go ahead and install the bolts. Once again it’s always a good idea to go ahead and use a criss-cross pattern. Now it’s time for the clutch pushrod or lifter rod. And the clutch lifter itself with the thrust bearing. And then we’re going to start installing our clutch plates. We’re just going to go ahead and do it just as they came out. Then our pressure plate goes on. Put on our springs and our bolts. And this one’s going to go in a
criss-cross and gradually. Once again you want to make sure it’s nice and flat. We’re going to put our outer clutch cover on. Once again in a criss-cross pattern. Now we can go ahead and install in the
frame. We’re going to kind of jump ahead. We’re installing our stator plate with our K&L Impact Screwdriver making sure those are nice and snug. We need to put our clutch actuator arm back in. And it’s set screw. Now we’re going to install the flywheel. Using our Tusk Clutch Hub Holding Tool that also doubles as a flywheel holder. Tighten that nut up. We’ll install our ignition cover and that completes the bottom end.

100 comments on “Motorcycle Bottom End Rebuild | Part 3 of 3: Final Assembly

  1. i have a 99' honda cr250 2 stroke which looks very similar to this, while doing a clutch replacement the thrust bearing fell on the floor as i took the basket cover off, when putting it back together i noticed the clutch would not engage so i took it apart again and it seems like there is supposed to be a spacing washer/ball bearing that sits between the pushrod and thrust bearing although i never found one on the floor where i dropped it and can not find information regarding this. Is there supposed to be a washer/ball bearing there? your help would be appreciated!

  2. This video is one of the best I've seen. I look forward to more of your mechanical illustrations. I race enduros and have 03 and 06 KTMs (EXC and XCW). This video will be useful.

  3. if i were to replace the ride side of the crankcase on a 2002 cr 125 do i need to get new barrings or just see it and find out. i wanted all the parts in front of me before i started that why i asked. thanks good tutorial taught me alot

  4. On the plate behind the stator (the one held in by Philips screws), there is room for adjustment counterclockwise/clockwise, isn't that for timing? Does this need to be adjusted after a full engine rebuild.

  5. all of you guys at rocky mountain deserve a pat on the back your service is the shit and it's awesome how you guys put things out like this and reply to any questions it shows you care about your customers and enjoy riding and fixing bikes as much as we do! keep up the good work you'l always be my main source for product/service!

  6. Hi, Im just taking my clutch apart and i just want to know if their is a certain way the clutch plates have to in.
    Like does each individual clutch plate have a certain position or can you just chuck them in?

    Its for 2008 250 ninja
    Thanks 🙂

  7. Technically, how long should it take a,motorcycle shop to do a complete top and bottom end in (hrs)

    hours top, & hours bottom

  8. I too appreciate the fact that you put these videos on youtube.  Even more that you do respond to questions and comments.  guys like me spend more time trying to keep my kids bikes going than riding my own, and businesses/people like you help guys like me a lot!  I purchase a lot from RM ATV and will continue!  Thank you!

  9. How long does this process take roughly ? i know you did about 20 minutes worth of Video, but do recognize its time consuming. I think when I called a dealer they wanted to charge for like 7hrs of time…

  10. hey i got a 82 yz 250 but i feel like there is too much space for the clutchplates in the basket.. i put everything together how i took it apart but the clutch doesnt work.. can you help?

  11. @Dan Kasy From what I can see your clutch should consist of 7 friction plates and 6 drive plates. I would recommend referring to the OEM diagrams https://www.rockymountainatvmc.com/oem-parts and go through your clutch again. It sounds to me like you could be missing something. Do you have your cable adjusted correctly? You can also refer to our Clutch Replacement for Motorcycle and ATV – Clutch Kit Install for instructions on rebuilding your clutch and adjusting your lever free play. If you have any other questions please let us know!

  12. I will be aquiring a 2003 yz250 th his weekend. The owner says the kick broke off wen he tried to start it after rebuilding the top end after seeing this video I realise there is no way for a piece of piston to be inside the transmission so im wondering how could this be? Please help before I make a wrong decision on getting this bike

  13. i have a question about liquid gasket, when you installed case together , a liquid gasket comes out on case it's no problem we can clean, but what happend when liquid gasket comes inside to case , thats no problem?  

  14. Should you only use a very small amount of yamabond when applying it to the case and what kind should be used for kawasaki

  15. "sweating" in the bearings into the case, as well as sweating in the crank into the bearings is way better than to use some wierd special tools wich maybe wont place everything correct. IN MY OPINION! 🙂 (cheaper too)

  16. I am rebuilding my 01 rm 250 and I had to replace the main bearings. How can I be sure that the bearings were seated perfectly? It almost seems that  one of the bearings sticks out a tiny bit higher than the other. Also the gasket maker I used between the main cases dries so by the time I pushed the cases together I didnt get a proper seal. What is a good gasket maker that will not dry fast and give me the proper seal?

  17. Hello, I am in doubt which brand of 250F will buy, what do you think is the best? which has a higher durability in your engine? Yamaha Suzuki Honda Kawasaki?

  18. i have a 05 yz 250 tore it aprart because it would not shift in to third or any higher gear now its back togther and wont shift higher than first   want could be the problem? thanks in advance glen..

  19. I have a 90 RM 250 and is leaking oil from the oil seal where front sprocket goes and I was wondering if I have to split the motor to replace the seal?

  20. Hello I got a 94yz 250 and I blew the bottom end I need to get my crank rebuilt is this process the same for my engine😁 I never done this before I'm new to this

  21. I have a kx 250 and i am reinstalling the crank. When you press it back into the case how do you know when it is as far in as it needs to be?

  22. Hi, i have an rm250 and there is oil leaking out of a machined hole in the case, is this due to a crank seal or the middle case gasket? any info is helpful, im rebuilding the bike as a senior project and plan to try things i havent before. I hope to use this video as a guide because itnis really helpful

  23. Do you torq your case half bolts to spec or is hand tight fine? Also can you tell me if any of these parts MUST have lock tight or is it just a good idea to do that for most of the inside screws?

  24. Where would you buy the special tools needed?I have 00 yz125, any chance you have the tool numbers handy?Great videos!!

  25. hey , I have a 2001 cr 125r , I split the cases to change the crankshaft , I put the transmission back in exactly how I took it out , the gears move freely & was able to move the gear drum through gears , when I put my cases back together , & I went to the shift shaft & the gear drum & clutch , and everything else , I put the gear shifter on to see if it wouldn't shift , it didn't shift , it will move up & down just a tad pit but not enough for shifting to occur, help ? been stuck for a while

  26. do I need that tusk clutch holding tool to change out my right side crank seal?

    which is causing my bike to run really rich and SMOKE A LOR. I have no power just bogging and splurge. a lot of black stuff coming out of my exhaust

    also to add, I'm losing so much trans oil every time I fill her up. I will ride & it does that whole process begins. I haven't ridden my cr250 since discovering this problem.

  27. Do you have a video that shows how to put the transmissions gears back together? I took mine apart in pieces instead of all together. I'm referring to the service manual but it isn't detailed enough.

  28. HELP! Installed crank on my 96 kx 250 when i put the cases back together it pulled the crank all the way to my stator side giving more space between the crank and cases on the clutch side! Is there a specification for clearance between crank and cases on either side?

  29. I just finished a build on my 1997 rm250 and the shifter moves fine but my bike will not go into neutral… how can I tell if I put the shift drum in correctly

  30. What's it mean when 2 strokes rev by them selves after a crash when the carb is fine I was told it means there's a hole in a gasket on the case.

  31. Thanks a lot for this series. Looked for hours for a free 97 cr125 manual with no luck and than your fine video work gave me my answers in minutes.

  32. hey ive just rebuilt my yz250 04, yet to start it an add gearbox oil but does the clutch actuator arm move all the way up and down like theres nothing there?

  33. awesome ive watched all 3 videos multiple times, im going to give it a go next weekend… What year was this YZ250 btw?

  34. Can I pull the inner clutch cover off of my 2008 KTM 450 EXC without taking out the inner clutch components? Just need to retap the oil check bolt.

  35. I'm attempting my first case crack and rebuild. Will all of the parts/gears/bearings etc. shown here be exactly the same as on my 2001 YZ250? I don't know the names of each part going back in the case and would use the video as a means of inventory when putting it back together.

  36. Good video ! Gah im looking into buying a CR 250 that needs a top end. and im considering just doing bottom and top end and start 100% fresh. But dam it would not be easy. The biggest thing for me is working with transmissions and all the gears and washers.

  37. Hi! Could you do a bottom end rebuilt on a ktm exc 525? My bike has 190h on it, do you think i need to do a bottom end rebuilt on it? It runs great right now. Or is it enough to do a top end rebuilt?

    thanks!

  38. Hi im doing this on a 1997 kx100 and ive done this with my 2002 yz125 before and I put the 125 transmission in wrong and i believe its because it wasn't spinning freely when i put it in and had to get that done professionally. The kx100 transmission spun freely before i put the other case half on but since i put the other case half on it doesnt spin freely anymore. Is that supposed to happen or do i have to re do it?

  39. what is the Yamabond number you use in this video. I notice on the website that you have 4, 5, 6b, and 7. I want the same grey colored stuff that you use.

  40. My countershaft bearing is giving me a load of trouble. I have tried time and time again to get it to work and also replaced it. The bearing spins freely when it is outside of the case. When it is pressed into the case it has a ton of resistance to spin. Has anyone else had a problem like this?

  41. To make the bearings last longer you should have greased the inner part of the bearing where the crank and piston meet

  42. so….according to the 4 videos I've just watched (1 other was the top end rebuild) and assuming you have all the parts that need replacing, a full engine rebuild would take 2 hours? maybe less? what if the crank shafts is broken? I have a feeling this will be the case on my RS 125 I'm buying to fix up. hmm

  43. You guys make it look so easy, thanks for the step by step tutorial, I feel confident I can do this and refer to the video ,

  44. Finished rebuilding my 99 yz250 and it clicks when rolling in neutral, theres also a neutral between last 2 gears and pops into gear when you rev in neutral sometimes. struggles to shift 1st to 2nd too… any thoughts???

  45. My back tire locked up no matter what gear I have it in when it's a neutral will not roll at all any idea what happened

  46. You make look way to easy
    I rebuilt 3 of my motors and every time i forget where all the parts go to hahahaha ….
    Nice video though …

  47. Good job, very thorough. I noticed you did not mention anything about torque specs but was using a torque wrench?

  48. I have looked on the work shop manual for the different size bolts used on the outer crank case cover nothing mentioned just torque settings. There's 15 bolts not including the bolts for the water pump, in this there is 4 different sizes in bolts. There's 8 the same size, i'm guessing they are for the outer case only, the others are for the clutch cover some of which go right through to tighten the outer case cover.

  49. Very good video!! I would like to know if I can be motorcycle tech on line training.im auto tech for couple years.it won't be any diferent.please let me know.thanks. keep it up.

  50. Why cant you shift through gears with split cases? Im sure honda can, my wr450 says its possible in the manual but its not letting me , exact same thing happen with my bike like in video. Is there a problem or is it just because is yamaha? It was shifting fine when closed but it writes in manual i can check if everything works smooth with it open

  51. Hi,Rocky Mountain,

    I've just replaced a crankshaft on my Yamaha YP 250 Majesty 2001 4str.

    It has gone back in ok, and I have fitted the two crank case halves back together. The oil/water pump shaft is rotating correctly, and is not jammed.

    The problem is that the whole assembly seems a little stiff, I can only turn it with a spanner on the spline end – it goes 360, but it's stiff – any ideas,please , anyone, or is this normal, and will it turn on the starter, and 'bed' itself in do you think?

    Cheers, Den, Swansea

  52. This video has been a lifesaver. Without it, I don't think I would have been able to tackle the rebuild on my '06 yz250f. God bless!

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