Honda CRF450R Bottom End Teardown

As part of our 2005 Honda CRF450R engine rebuild project, we’ve removed the engine and torn down the top end. Now we’re tearing the bottom end down to the crankshaft. 

We'll be rebuilding our CRF450 engine using a combination of OEM and Wiseco Garage Buddy kit parts. The Garage Buddy rebuild kit includes everything you need to do the bottom end, including the crankshaft, seals, bearings, gaskets, O-rings, timing chain, etc.

Watch the video above and follow the steps below to see how to break down the bottom end of a 2005 Honda CRF450 engine. 

NOTE: The steps below are a summarized breakdown of the main bottom end components. There are many more parts that come off than what’s detailed below, so make sure you watch the entire video and lay out and label everything as you take the bottom end apart to avoid making mistakes when putting stock pieces back together.

Honda CRF450R Bottom End Teardown Steps

Step 1. Remove the bolts that hold the outer clutch cover in place, followed by the cover itself. 

Step 2. Remove the bolts that hold the clutch disc cover in place, followed by the clutch cover and the discs themselves.  

NOTE: If you’re going to reuse the clutch, remove the bolts out a little at a time to bring everything out evenly. Otherwise, you run the risk of damaging the basket. 

Watch the clip below to see the clutch removal segment of our Honda CRF450 bottom end teardown video.

Step 3. Use a chisel and a soft-blow hammer to open up the stakes on either side of the central nut, then use an air ratchet to get the nut off. Remove the washer, the locking washer and the bearing for the clutch basket. 

NOTE: You have to remove the crankcase cover and several other parts such as the water pump before you can get the clutch basket out.

Watch the clip below to see the clutch basket removal segment of our Honda CRF450 bottom end teardown video.

Step 4. Remove the bolts that hold the water pump cover, followed by the water pump cover, impeller and the pump itself. 

Watch the clip below to see the water pump removal segment of our Honda CRF450 bottom end teardown video.

Step 5. Remove the bolts that hold the crankcase cover in place, then gently knock the cover off with a soft-blow hammer. 

NOTE: Don’t pry the cover out with a screwdriver, since you don't want to damage that surface and end up with a leak. Also, pay attention to the little hose on the back, as well as two dowels and an O-ring that you don’t want to lose.

Watch the clip below to see the water pump removal segment of our Honda CRF450 bottom end teardown video.

Step 6. Remove the clutch basket. 

Step 7. Remove the starter intermediate gear and the return spring. To get the spring off, remove the split collar first to give you enough room to lift the spring and bring it out.

Watch the clip below to see the starter gear removal segment of our Honda CRF450 bottom end teardown video.

Step 8. Remove the stator cover bolts, then gently tap out the cover itself with a soft-blow hammer and remove the stator. 

Watch the clip below to see the stator removal segment of our Honda CRF450 bottom end teardown video.

Step 9. Remove the sprocket cover, the bolt that holds the sprocket in place and the sprocket itself.

Step 10. Remove the nut that holds the flywheel in place, followed by the flywheel itself with a Honda rotor puller. 

Watch the clip below to see the flywheel removal segment of our Honda CRF450 bottom end teardown video.

Step 11. Remove the drive chain, the chain tensioner guide and the oil pickup pipe. 

Step 12. Remove the circlip off the drive gear for the oil pump, followed by the drive gear itself. 

NOTE: When you're removing the circlip, open it just enough to get it off. Otherwise you're going to stretch it out and it won't hold it in place. 

Step 13. Remove the pickup tube.

Step 14. Break loose the nut for the crankshaft drive gear without removing it.

NOTE: You’ll need a special gear holder tool for this step. Temporarily put the clutch basket back in, then put the gear holder in place and use an impact to break the bolt loose.

Step 15. Hold the gear still and use a lock nut wrench to remove the nut that's holding on the counterbalance, then remove both the drive gear and the intermediate gear.

Watch the clip below to see the crankshaft gear removal segment of our Honda CRF450 bottom end teardown.

Step 16. Remove the shifting mechanism by lifting it straight out. Don't lose the washer that comes out with it. 

Step 17. Remove the bolts and covers that hold down the shift drum, followed by the shift drum itself.

Watch the clip below to see the shifting mechanism disassembly segment of our Honda CRF450 bottom end teardown.

Step 18. Remove the counterbalancer, followed by all of the remaining bolts on the crankshaft and the drain bolt from the transmission, making sure not to lose any of the washers that go with the bolts.

Step 19. Separate the crankcase halves by gently tapping points on the right side with a soft-blow hammer to get them to part. 

PRO TIP: The crankcase on our Honda CRF450R was heavily corroded, making it difficult to split the cases. If you’re having difficulty splitting the halves on your crankcase, attach a crankcase splitter tool, and use a soft-blow hammer and a chisel with the tool to pull the crankcase apart.

Watch the clip below to see the crankcase splitting segment of our Honda CRF450 bottom end teardown.

Step 20. Pull the transmission out by first removing the shift forks.

Watch the clip below to see the transmission removal segment of our Honda CRF450 bottom end teardown video.

Step 21. Gently tap the crankcase out and remove it.

Watch the clip below to see the crankshaft removal segment of our Honda CRF450 bottom end teardown.