How To Install The Piston On Your 97-01 Honda CR250
The Tools You Will Need
- Feeler Gauges
- Small Pick
- 2-Stroke Oil
- Assembly Lube
- (Master Tools & Parts List Below)
The Parts You Will Need
- New ’97-’01 Honda CR250 Piston Rings
- New Piston Pin Clips
If you are installing a new piston, I suggest a Pro-X piston kit. It’s a cast piston, so it’s a little heavier than forged, but it costs much less. Pro X is distributed and supported by Wiseco, so if you have any questions, you can just call.
I already put together an article covering piston selection, so I’m not going to go into that here, but a cast piston works for me because I will be installing it in a bike I use for enduro.
- I recommend opening the Service & Torque Specs in a new tab for easy reference.
- If you need parts and tools, make sure to buy them on Amazon!
- Pictures with captions are after the steps below.
- If you need any help don’t hesitate to ask!
Gap Your New Rings
- Before we install the piston rings, we need to make sure the end gap is within spec.
- Place each ring into the bottom of the cylinder, and push it down with the piston.
- Measuring the ring gap with a feeler gauge.
- The end gap on both rings should be no greater than 0.026 inches.
- If the rings are too tight, you can file the ends with a fine metal file until they are in spec.
Pin Clip Install
- Install the first piston pin clip into the pin bore groove.
- Your thumbs and a small pick should work just fine, but be careful not to gouge the cylinder with the end of the clip.
- Rotate the clip, so the opening faces up.
Piston Ring Installation
- Double-check that the rings are clean and dry.
- Lubricate the piston edge and ring grooves with 2-stroke oil.
- Check that the IT mark is facing up, and align the bottom ring with the alignment pin.
- Spread the ring just enough to clear the piston, and install straight down, do not try to wrap the ring into the groove.
- Check that the ring is free in the groove.
- Repeat for the top ring.
- We are using oil to install the rings, but the oil needs to be thoroughly wiped off afterward.
- Lubricate the pin and pin bore, and press the pin into the open side of the piston.
- Apply assembly lube to the connecting rod opening, and install the needle bearing, then apply lube to the inside of the needle bearing.
- Position the piston over the connecting rod, so the IN marking is facing the rear of your bike.
- Press the pin through the connecting rod, and seat it against the pin clip on the other side of the piston.
- Install the second pin clip with the opening facing up.
- Before you move on, place your piston holder to keep it in place.
← Part 10: Exhaust Valve Installation
Part 12: Cylinder Installation →
Top End Rebuild Tools List: (Links to Amazon)
- Piston Pin Puller
- Piston Holder
- Machinists Straight Edge
- Feeler Gauges
- Telescoping Bore Gauges
- Digital Calipers
- Plastic Scraper
- Spark Plug Thread Follower
- Motion Pro Torque Wrench Adapter
- Molybdenum Grease
- Lithium Grease
Top End Rebuild Parts List: (Links to Amazon)
Keep Your ’97-’01 CR250 Running Right!