1997-2001 Honda CR250 – Top End Service – Part 10: Exhaust Valve Installation

How To Install The Exhaust Valve On Your 1997 – 2001 Honda CR250.

1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve InstallationThe Tools You Will Need Are:

  • 4mm Hex Wrench
  • Needle Nose Pliers
  • 2-Stroke Oil
  • Molybdenum Grease (Amazon)
  • Inch Pound Torque Wrench
  • Rubber Gloves

The Parts You Will Need Are:

  • Left Valve Cap O-ring – Part Number: 91302-001-020

If you don’t have your parts yet, you can get them from RockyMountianATVMC.com

Related: Should You Trust The Oil Injection System On Your 2-Stroke Motorcycle?

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

Exhaust Valve Linkage Assembly

(Click To Start Slide Show)
Start by assembling the linkage.

  • Insert the bushing into the valve link, small side down
  • Install the spring with the spring ends facing up.
  • Compress the spring, and rest it in the stop.
  • Place the drive pinion on top of the linkage with the pin between the spring ends.
1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Assemble Linkage 1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Linkage Assembled
Apply grease to the drive shaft bushing and driveshaft.

Fit the bushing on the drive shaft, and Install drive shaft part way into the cylinder

1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Grease Drive Shaft Bushing 1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Grease Drive Shaft
Align the link assembly, and finish installing the drive shaft.1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Align Linkage With Drive Shaf
Clip the driveshaft into the linkage.1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Clip Drive Shaft To Linkage

Exhaust Valve Governor Install

Apply grease to the pinion shaft and bushing.

Seat bushing in the crankcase.

1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Grease Pinion Shaft Bushing
Assemble the governor washers and engage the rack.

Install the governor in the crankcase

1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Install Governor and Rack
Install pinion shaft with the opening facing in.

Double check the rack and pinion operation.

1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Pinion Shaft
Flap Valve Assembly
Apply grease to the flap valve shaft, and partially install it into the cylinder.1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Grease Flap Valve Shaft
Install the flap valve with the projections facing up.

Align and install the flap valve.

  • 97-98 – Through the exhaust port.
  • 99-01 – Through the cylinder
1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Install Flap Valve
Right Sub-Exhaust Valve Install
Apply grease to the exhaust valve shaft, and connect it to the valve.1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Asssemble Sub-Exhaust Valve a
Align the valve shaft with the flap valve, and place the sub-exhaust valve on it’s bore.

Apply 2-stroke oil to the valve, then press the valve into the cylinder.

1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Install Valve Shaft
Turn the valve until the cutout is facing up, and install the stopper bolt hand tight.1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Install Stopper Bolt
Install bearings with the manufacturer’s marks facing out.1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Right Side Bearings
Connect Valve Linkage
Seat the valve link against the end of the valve so the tab sits in the cutout.

Rotate the valve counter clockwise, and insert a drift into the hole.

1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Tighten Valve Linkage
Install the hex bolt and torque to 48 in-lb.1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Torque Valve Linkage
Left Sub-Exhaust Valve Install
Lubricate the left Sub-Exhaust valve with 2-stroke oil.

Align the valve with the valve shaft, and press it into the bore.

1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Left Sub-Exhasut Valve
Lubricate and install the bearings with the markings facing out.1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Left Side Bearings
Install the collar with the stepped side facing in, followed by the snap ring.1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Left Side Collar1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Left Side Snap Ring
Lubricate a new o-ring, and install it on the valve cap.1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Fresh O-ring
Apply grease to the valve cap threads, and install the cap hand tight.1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Grease Valve Cap
Test Power Valve Operation
Tighten the hex bolt on the pinion holder temporarily, and test the operation of the exhaust valve system.1997 - 2001 Honda CR250 - Top End Service - Part 10 - Exhaust Valve Installation - Tighten And Test Linkage
Loosen the pinion bolt, as you will need to adjust the system after the cylinder is installed.Be Careful!
Exhaust Valve Torque Specifications
Linkage Hex Bolt48 in-lb.
Pinion Hex Bolt48 in-lb.
Part 9: Clearance CalculationsPart 11: Piston Installation
1997 - 2001 Honda CR250 - Top End Service - Part 9 - Clearance Calculations1997 - 2001 Honda CR250 - Top End Service - Part 11 - Piston Installation

 

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