Engine Tear Down

[blueoval]

I am going to tear the engine down and replace the crank seals and check/measure clearances/inspect/etc the engine.  Do you guys tear the engine partway down while it's in the bike like the Clymer manual states - removing the cylinder head, removing the cylinder, piston, clutch, etc.  Or do you take the whole engine out of the chassis then tear it down?  thx ted

[KXcam22]

Ted,
  I like to remove the whole engine first.  That way it is easier to give the exterior of the engine a good cleaning in all the nooks and crannys before tearing it down. Cam.

[Dutch-K5 Fan]

These things can be done in the frame.
I agree with cam to take the engine out. It doesn't take much more time and works alot bettter.

Dutchie

[blueoval]

Thank you Dutch and Cam for the advice.  I will start tonight. 

[Friar-Tuck]

  BlueOval,
 Like the other guys said, getting the engine out and on the bench will keep "stuff" from finding it's way into your crankcase, and working on the bench is easier on you.
   Making a small "box" to hold the engine relatively upright is handy.

   There will be a few specialty type items you will need to get the flywheel off,
 
  http://www.rockymountainatvmc.com/productDetail.do?navType=type&webTypeId=203&navTitle=Engine&webCatId=17&prodFamilyId=17329#vehicleSelect
 
 and something to Split the Cases.
 http://www.rockymountainatvmc.com/productDetail.do?navType=type&webTypeId=140&navTitle=Tools%2FShop&webCatId=22&prodFamilyId=17167

 Several guys have made their own tools to separate the cases, and improvised.
   An impact will spin off the clutch nut, and either a gear jam,

http://www.rockymountainatvmc.com/productDetail.do?navType=type&webTypeId=140&navTitle=Tools%2FShop&webCatId=22&prodFamilyId=22841

   Or something to hold the clutch/crank
 http://www.rockymountainatvmc.com/productDetail.do?navType=type&webTypeId=140&navTitle=Tools%2FShop&webCatId=22&prodFamilyId=18289
   I have to admit I have used a penny (metal softer than gear) to jam  gears to be able to check  the torque  on things in the past.   
   
  Gaskets,seals and consumables will run around $110.00
 The tools you either build or buy can be used on your other bikes. 
   
 I know it's discouraging to have  just gotten a bike and then have to go through all this,
     Hang in there, when you get this old girl up to snuff you will be able to blow the handguards off 90% of the $8,000.00 dirt bikes you come up against in the field.   

   Hopefully some of the other guys will have some more input.

 You have made a good decision, lots of folks these days don't want to make the hard choices.
    Tuck\o/

[DoldGuy]

I recently invested in the Case Splitter mentioned above & it made the job extremely easy & works better than any of MY homemade pieces. I know others here are gifted in making such things, but, this is far better than what I could do & it is reasonably affordable. Wish I had invested in it long ago. One thing that happened during my tear down was the crank bearings stayed on the crank & not in the cases & my bearing splitter was to thick to get behind the bearing so I took the crank to my buddies at Pro Class Cycles (put a plug in for you Bob) to remove & his splitter was just as thick. He told me to lookaway (I will not post here how he did it / if interested PM me) and the bearing was 1/4 of the way off. Then went to his press & finshed the job. After his method we chocked it into the truing stand, it measured good with only .003" run out.
Thanks Again Bob!

DoldGuy

[blueoval]

Would one of you be able to send a picture of the "box" or whatever it is that you use to hold the engine on the bench.  I am very familiar with race car engines and rebuilding them, so now I am going to learn the 2 stroke.  thx

[ShadeTreeFab]

i use my bike stand, a cheep case splitter at autozone "import timing gear puller" & two long metric screws from ace hardware.
if your not real familiar with the motor use a digital camera and take pics.

[Friar-Tuck]

  Here's a setup one of the guys on the board put together.
( Scroll down his pic's to get an idea  of what you'll be up against as far as clearance etc.)

  BDI does more than your average bear, so this may seem a bit much for the one engine a year set up.   
    http://www.kxriders.com/forums/index.php/topic,5163.0.html

 I have some small pieces of 2x4 and 2x6 I stack up, and some 1/4 and 3/8 rod about 18-20" long
 to run through the engine mounts when you need to hold back to tighten /loosen.

  I'll see if I can find some photo's of some different Idea's   
  Tuck\o/

[blueoval]

That is sweet Tuck.  Thanks for the photos.  Picture is worth a lot.  Completely get the idea now.  This site is just awesome.  Really appreciate the offer to borrow the tools.  I am hesitant to borrow someones stuff, but may take you up on the offer.   ted

[Friar-Tuck]

 
  Oky-Doke..
   Blue Oval just let me know.   Spend some time doing a bit more research, and  you will be
 Fine.    There is another recent thread about replacing/inspecting a clutch.   One of the all too common errors  has happened to the Chap, the bolts holding the pressure plate on the clutch got overtightened and snapped off the heads of two bolts.
 
Which is better than snapping off the tower.
                         ( Please don't ask me how I know that one... )
             
    I don't want the guy to feel any worse,
  but the torque value for those 6mm bolts is only like  4.5 ft.lbs  or 6N.m (+threadlock)
    Cam 22  wrote back to the guy with some helpful hints on how to possibly save the basket.  about an $80.00 part...
      There is other clutch related things to watch out for, When you get that far spend a few moments and see what you can find and then ask about anything you may have missed.
   I think that's probably how to get the most out of us and the site.
  Tuck\o/

[ShadeTreeFab]

 
 
Which is better than snapping off the tower.
                         ( Please don't ask me how I know that one... )
             
 i learned that one to

[KXcam22]

I have never snapped a tower off but I once used a too-small nail to jam the primary/clutch gear and it went through the gears (when I was torquing on the primary gear retaining nut) and bent the crank tip. Oops. Cam.