1997-2001 Honda CR250 – Bottom End Service – Part 1: Removal & Disassembly

How To Remove And Disassemble The Crankcase On Your 1997 – 2001 Honda CR250.

1997 - 2001 Honda CR250 - Bottom End Service - Part 1 - Removal And DisassemblyThe Tools You Will Need Are:

  • 8mm Socket
  • 14mm Socket
  • 22mm Socket
  • Mallet
  • Wood Blocks
  • Towels
  • Big Hammer
  • Plastic Scraper
  • Flat Razor
  • Dremel with Sanding Disc
  • WD40
  • Paper Towels
  • Safety Glasses

The only specialty tool you will need is a case splitter, and you can get one through our partners here.

Set up your bike, so it’s as sturdy as possible; you may need to get aggressive during removal.

Click Here To Open The Bottom End Specifications Table In A New Window

Bottom End Removal:

(Click To Start Slide Show)
You have three bolts attaching the bottom end to the frame, two mounting bolts, and the swingarm pivot shaft. 1. Two Mounting Bolts and Swingarm Pivot Bolt
Start by removing the swingarm pivot shaft first, because I have never had one come out easy.2. Remove Pivot Bolt First
You may find yourself with a seized shaft. The only thing you can do is hose it down with anti-seize, then wait, then hit the bolt with the biggest hammer you have, then repeat as needed.3. Pivot Bolt Will Be Stuck
You will need a new pivot bolt, but they are not too expensive.
Remove the two lower mounting bolts, and keep track of their direction for install.4. Remove Mounting Bolts
Remove the engine from the frame. The swing arm may be resting on the rear of the case, so lift the front end first and give it a jiggle. But do not lift the case by the crankshaft like this impatient idiot.5. Remove Crankcase From Frame
With the case removed, clean and inspect the frame.

Crankcase Disassembly:

Lay your crankcase on your blocks with the left side facing up. Loosen the 11 crankcase bolts in a criss-cross pattern, ¼ turn at a time until they are all loose.6. Loosen Case Bolts
The crankcase bolts vary in length, so outline the case on cardboard or styrofoam and place your bolts accordingly.7. Organize Case Bolts
Assemble your crankcase splitter and attach it to the case.9. Split Case
Remember to keep the splitter parallel to the case.8. Assemble Case Splitter
Begin tightening the splitter nut.9. Split Case
After every turn, firmly tap the case seam with a rubber mallet. Make sure to check the case gap frequently if the case is separating unevenly, back out the splitter nut to remove pressure from the case. I had to tap aggressively on the front of the case where a dowel had seized.10. Tap With Mallet
With the cases separated, remove the two alignment dowels, o-ring, and gasket material.11. Remove O-ring and Dowels
Transmission Removal:
Take every precaution you can when handling the transmission. Keep it oiled, wrapped, and clean at all times.12. Remove Shift Shafts
Remove the two shift fork shafts, followed by the shift drum, and the shift forks.13. Remove Shift Fork14. Remove Other Shift Fork
Remove the main shaft and countershaft as a unit, keeping the gears meshed.15. Remove Shift Drum
Wrap the assemblies in a towel and set aside.16. Remove Mainshaft And Countershaft 17. Keep Shafts Meshed
Crankshaft Removal:
Flip the right crankcase, so the outside is facing up, and place a layer of towels under the crankshaft. Attach the crankcase splitter with WASHERS… and press the crankshaft out of the case.18. Assemble Splitter On Right Side
Again, remember to keep the splitter parallel to the case.19. Press Crankshaft Out Of Case
If your main shaft bearing comes out with the crankshaft, you will need to use your bearing splitter to remove the bearing from the shaft.20. Keep Pressing

Clean:

The mating surfaces must be spotless and smooth to ensure a tight seal. Start by removing all gasket material from the mating surfaces with part cleaner and a plastic scraper. With the big pieces gone, move onto the tough spots with a flat razor, taking extra care not to gouge the surface.

21. Clean Case HalvesWith all the gasket material gone, give the surface a once over with a fine grit sanding disk. If you don’t have a Dremel, 600 grit emery paper will work just fine. You want to have a smooth almost mirror finish when you are done.22. Sand With Dremel of 600 grit Paper This case has quite a few rough spots left over from casting. I have the equipment and the time, so I am going to smooth those out while I have to opportunity.22.1 Dremel Left Over Casting Remove Seals:

Remove the oil seals from the crankcase. Make sure to use a towel to protect the body.23. Remove Oil Seals Thoroughly wash the crankcase with water and solvent. Thoroughly dry with compressed air, and coat with a layer of WD40.24. Clean And Coat with WD40Inspect:

With your case clean and shiny, check for any unusual wear or cracking. Inspect the crankshaft for cracks, rubbing, pitting and heat damage.

Check the connecting rod for play.

If something doesn’t look right, take your crankshaft to a machine shop or dealership to check the runout and connecting rod radial clearance.

This crankshaft is nonrepairable, and if it is out of spec, you need to replace it entirely.25. Inspect Crankshaft

Intro: Tools & PrepPart 2: Transmission
1997 - 2001 Honda CR250 - Bottom End Service - Tools And Prep - Featured1997 - 2001 Honda CR250 - Bottom End Service - Part 2 - Transmission Service

 

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