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.

Honda Engine Rebuild Wiseco Garagre Buddy kit

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

Honda CRF450 engine rebuild bottom end teardown

Honda CRF450 bottom end teardown clutch cover

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

Honda CRF450R bottom end teardown clutch removal

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. 

Honda CRF450R engine rebuild clutch plates

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. 

Honda CRF450 bottom end teardown clutch basket

Honda motorcycle engine rebuild bottom end teardown

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. 

Honda CRF450 bottom end teardown water pump cover

Honda CRF450 bottom end teardown water pump impeller

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. 

Honda CRF450 bottom end teardown crankcase cover

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.

Honda CRF450R engine breakdown crankcase cover

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. 

Honda CRF450R clutch basket removal

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.

Honda CRF450 engine teardown starter gear

Honda CRF450 motorcycle bottom end teardown

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. 

Honda CRF450 bottom end teardown stator cover

Honda CRF450 engine teardown stator removal

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.

Honda CRF450 bottom end teardown sprocket

Honda CRF450R motorcycle bottom end disassembly

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

Honda motorcycle rotor puller tool

Honda CRF450 engine flywheel removal

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. 

Honda CRF450 bottom end teardown chain removal

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

Honda CRF450 motorcycle engine disassembly

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.

Honda CRF450R engine teardown bottom end

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

Honda CRF450 bottom end teardown crankshaft drive gear

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.

Honda motorcycle gear holder tool

Honda motorcycle lock nut wrench

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.

Honda CRF450 engine disassembly bottom end

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. 

Honda CRF450 shifting mechanism removal

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

Honda CRF-450 engine teardown shift drum removal

Honda CRF450 shift drum removal

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.

Honda CRF450 dirt bike bottom end teardown

Honda CRF450 dirt bike engine teardown

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

Honda CRF450R crankcase splitting

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.

Honda CRF450 engine crankcase splitting

Honda CRF450 engine crankcase halves splitting

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.

Honda CRF450 engine transmission removal

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.

Honda CRF450 engine crankcase removal

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

 

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