1997-2001 Honda CR250 – Bottom End Service – Part 2: Transmission Service

How To Service The Transmission On Your 1997 – 2001 Honda CR250.

1997 - 2001 Honda CR250 - Bottom End Service - Part 2 - Transmission ServiceInspecting your transmission is not a hard job, but it does require cleanliness, organization, notes, and math.

No matter what you find during your inspection, you WILL need three new snap rings, as the old ones will deform when you remove them.

As you go, measure the inside diameter of the gears, and the inside and outside diameters of the bushings.

Inspect every part for visible wear, like broken teeth, cracking, gouging and pitting. If anything even looks damaged, you will need to replace the part.

If you need to replace any part of the transmission, make sure to buy through our partner links, its helps us a lot!

The Tools You Will Need To Service Your Transmission Are:

  • 4 Long Screwdrivers
  • Snap Ring Pliers
  • Calipers
  • Parts Cleaner
  • Towels
  • Safety Glasses
  • Notepad & Pen

Let’s start with the Mainshaft

Mainshaft:

The main shaft is the larger of the two shafts.

1 - Start With The Mainshaft
Start With The Mainshaft

Disassemble the main shaft, transferring every part, in order, to a long screwdriver.

2 - Transfer Gear Stack To Long Screwdriver
Transfer Gear Stack To Long Screwdriver
3 - Keep Things Organized
Keep Things Organized

The gear stack on the main shaft is oriented:

  • Washer
  • Second gear
  • Washer
  • Fourth gear and bushing
  • Spline washer
  • Snap ring
  • Third gear
  • Snap ring
  • Spline washer
  • Fifth gear
  • And first gear is the countershaft

Inspect and measure each gear, washer, and bushing.

4 - Inspect And Measure Countershaft Gear Stack
Inspect And Measure Countershaft Gear Stack

Measure the main shaft diameter at fifth gear, and inspect the splines, gears, and snap ring grooves.

Related: ’97-’01 Honda CR250 External Shift Mechanism Service

Record each measurement as you go.

5 - Record All Measurements For Later
Record All Measurements For Later

Countershaft:

The countershaft is the shorter of the two shafts and is disassembled from both sides.

6 - Transfer Countershaft Gear Stack To Screwdrivers
Transfer Countershaft Gear Stack To Screwdrivers

Remove each side to a separate screwdriver, cleaning and measuring as you go.

7 - Clean And Measure Countershaft Gear Stacks
Clean And Measure Countershaft Gear Stacks

The countershaft gears stack on the left side is oriented:

  • Washer
  • Second gear and bushing
  • Washer
  • Fourth gear

The countershaft gears stack on the right side is oriented:

  • Washer
  • First gear and bushing
  • Washer
  • Fifth gear
  • Snap ring
  • Spline washer
  • Third gear
  • Washer

Measure the countershaft at first, second, and third gear positions, and check the splines and snap ring grooves for damage.

Record every measurement as you go.

Clearance Calculations:

You will need to calculate the clearance between the gears and their bushings and the bushings with the shaft.

Here is a link to the service specifications. In the second table, you will see the various clearances that need to be measured and calculated.

Shift Drum & Forks:

Clean the shift drum, forks, and fork shafts.

8 - Clean And Inspect Shift Forks, Shafts, And Drum
Clean And Inspect Shift Forks, Shafts, And Drum

Measure each forks claw thickness, inside diameter, and guide pin.

9 - Measure Fork Claw, Pin, And Inside Diameter
Measure Fork Claw, Pin, And Inside Diameter

Measure the diameter of the long shift fork shaft at each end and center point.

Measure the short shift fork shaft at the center point.

Check the play of each shift fork in their respective gears.

  • Right shaft to fifth gear
  • Center shaft to third gear
  • Left shaft to fourth gear.

The forks should have a slight play in the grooves.

Shaft Assembly:

If everything has stayed in order, all you need to do is transfer your gear stack from your screwdrivers back onto the shafts.

10 - Reassemble Mainshaft
Reassemble Mainshaft
11 - Assembled Mainshaft
Assembled Mainshaft
12 - Reassemble Countershaft
Reassemble Countershaft
13 - Assembled Countershaft
Assembled Countershaft

Make sure to use plenty of assembly lube at every contact point.

During assembly, you will need to make sure your new snap rings and washers are facing the correct direction.

14 - The Washers And Snap Rings Have A Flat Side And A Rounded Side
The Washers And Snap Rings Have A Flat Side And A Rounded Side

Although both sides look flat, one side is slightly rounded.

Mainshaft Snap Ring And Washer Direction: (Flat Side, From Left To Right)

Washer: Left | 2nd | Washer: Right| 4th | Washer: Left | Snap Ring: Left | 3rd | Snap Ring: Left | Washer: Left | 5th | 1st

Countershaft Snap Ring And Washer Direction: (Flat Side, From Left To Right)

Washer: Left | 2nd | Washer: Right | 4th | Washer: Left | 3rd | Washer: Right | Snap Ring: Right | 5th | Washer: Right | 1stWasher: Right

Wrap your gear stacks in a clean towel and set aside until assembly.

Part 1: Removal & Disassembly
Part 3: Bearings
1997 - 2001 Honda CR250 - Bottom End Service - Part 1 - Removal And Disassembly1997 - 2001 Honda CR250 - Bottom End Service - Part 3 - Bearings And Seals - Featured

 

Fix Your Dirt Bike Logo

Keep Your ’97-’01 CR250 Running Right!

This site uses Akismet to reduce spam. Learn how your comment data is processed.