How To Inspect The Cylinder Head On Your 1997 – 2001 Honda CR250.
The Tools You Will Need Are:
- Plastic Scraper
- Soft Brush
- Shop Towels
- Spark Plug Thread Follower
- Metal Lubricant/Oil
- Mechanics Straight Edge
- Feeler Gauges
- Emery Paper
- Plastic Wrap
If you don’t have them yet, you can get a set of Feeler Gauges HERE, and your or a Machinist Straight Edge HERE.
Cylinder Head Cleaning
Clean the entire head with parts cleaner and a soft brush. Clean the cylinder head mounting surface with a plastic scraper.If you have carbon build up in the combustion chamber, soak it in parts cleaner, then gently scrub it off with a scouring pad.
Clean the spark plug threads buy threading a rolled up shop towel through the hole.
Check the water jackets are free of obstruction, and the mating surface is smooth.
You can smooth out small burs and pits with 600 grit emery paper, but be very careful, 0.001 inch could take your head out of spec.
Lubricate the spark plug hole, and gently run your spark plug thread follower all the way through the spark plug hole to correct any potential misalignment.If your threads are stripped out and your follower cannot correct them, you will need to install a Helicoil (link to RockMountainATVMC.com).
Inspect Cylinder Head Warp
Lay your straight edge across two adjacent mounting holes, and try to fit your feeler gauge underneath.
If the gap still exists, record the measurement.
Repeat this measurement around the head.
The warp limit for your cylinder head is 0.002 inch.
You may be able to bring your head into spec with a sheet of 600 grit emery paper.
Tape the emery paper to a sheet of glass, and dampen with water.
If you cannot bring your head back to spec, you will need to take it to a machine shop.
Clean your cylinder head with HOT soapy water, and rinse thoroughly.
Dry with compressed air and double check the mating surface for smoothness.
If everything looks good, apply a light coat of WD-40 to avoid oxidation, and wrap your cylinder head in plastic wrap to avoid contaminants until you are ready for assembly.Cylinder Head Hanger Plates
These have some dents on the top, but they are still straight with round holes.
|Part 5: Piston Inspection||Part 7: Cylinder Inspection|
Keep Your ’99-’01 CR250 Running Right!
- Service Specification
- Clutch Replacement
- Carburetor Service
- Engine Top End
- Front Fork Maintenance
- Rear Shock Rebuild
- Wheels & Tires
- Kickstarter Inspection
- External Shift Linkage