Jump to content

Removing Clutch Shaft Bearings

Recommended Posts

Several people have told me they never replace these bearings. Ive been trying to remove them for days with no luck. My friend called a few shops and they want $40 each. 

One technician at a smaller shop said he has to heat the case cherry and theyre still a pain. 

So far ive heated to about 230F. My bearing puller tool just slips out when i use high force. 

Been trying to do multiple lighter smacks. That worked for the other bearings as the collets in my set were not a good match for the bearing sizes in the yz250. 

Called the local auto parts and they dont rent blind bearing pullers. Searched around to buy individual collets at places like Zoro or Grainger. 

Anyone have advice? I feel like i have damaged the bearing by now so i really want to get them out. There are 2 in there. 

Share this post


Link to post
Share on other sites

Doing this to try and get a solid surface. Heating with a torch. Also tried the oven. 

How hot can i go in the oven? My buddy told me 400F is totally safe for the bare case. 

20181019_150406.jpg

Share this post


Link to post
Share on other sites

The problem you are having is your tool is also expanding the bearing. The collet must only expand that the end so the flange of the collet grabs the needles. Otherwise, you may have to cut the bearing to get it out. If you screw up, kiss the case goodbye.

Share this post


Link to post
Share on other sites

Correct I see how the collet has a lip at the end to catch behind the bearing. 

My problem is that the lip is not very pronounced and the tabs of the collet are able to bend.

If I smack the tool hard the collet just slips right out. 

The collet I'm using is too small. I'm having to expand it very wide. Ideally I would buy a slightly larger collet with a larger lip. 

The next size up in my set is too large to fit. I don't like my set because the smallest 3 collets vary is size too much. I struggled with several other bearings. My friend joked that I'm doing the definition of insanity repeating failure. But eventually the other bearings finally came out. 

Edited by wopachop

Share this post


Link to post
Share on other sites

In all the years I've been working on bikes I don't remember replacing to many of those bearings? If you aren't having luck with a blind hole puller which is the proper tool for the job. The only other way I could suggest is to break apart the bearing and bring it out in pieces? It's not that big of a bearing the casing shouldn't be that thick? Maybe a Dremel with a long burring bit on it to cut down bearing case and break it out in pieces? I hate when things don't go as planned, then you have to get creative!

Share this post


Link to post
Share on other sites
2 hours ago, Eric Nyysti said:

In all the years I've been working on bikes I don't remember replacing to many of those bearings? If you aren't having luck with a blind hole puller which is the proper tool for the job. The only other way I could suggest is to break apart the bearing and bring it out in pieces? It's not that big of a bearing the casing shouldn't be that thick? Maybe a Dremel with a long burring bit on it to cut down bearing case and break it out in pieces? I hate when things don't go as planned, then you have to get creative!

The only time Ive ever had to do anything with them is when someone brings me a new case and Ive gotta install them. Never once, in the probably 250+ engines Ive done have I ever seen a set worn enough to warrant pulling and replacing them. Now, with that said, you can bet your ass you've already done enough damage in there to require the bearing to be replaced.

1. Get the right sized collet to pull the bearing. It'll be the size of the shaft.

2. Try to bite the inside lip of the outer shell. If you cant, see if you can push the collet deep enough to get behind the needles and pull from there.

3. Use a MAP gas torch. Heating the entire case to 400 in the oven is useless, because the bearing heats up too. You need to get the collet placed and ready, heat and pull withing as few seconds as possible, before the case heats the bearing shell and your thermal expansion attempt becomes moot. Heating the cases and freezing the bearings to install works, heating the entire assembly is pointless.

I see you've got the Harbor Freight puller set and that's fine. You can get the right sized collet from Motion Pro, retap the collet and screw it right onto the draw hammer you have. I wonder how I know that? hmmmmmm

 

  • Like 1

Share this post


Link to post
Share on other sites

Motion Pro i will check them for individual collets!!! Any other possible places?

So far all i can find are complete blind bearing sets like i already have. 

Ive tried heating the case quickly and pulling right away. Even had pieces of ice cold paper towels resting on the bearing and collet in hopes to keep the bearings a little cooler than it would have got. 

One fella was saying metals have different amounts of expansion. So even if the bearing and case are the same temp the aluminum should have expanded more. 

I dont understand why these little bearings are such a pain compared to the 20 others i pulled out of the same engine? They dont see a high load. Any thoughts? Im just curious. Only difference is theyre needle. Are they designed as being an interference fit like the crankcase bearings maybe? Wish i had know to leave them alone. I figured just replace every bearing while its open. Owned the bike since 2003 and it mostly rides sand dunes. First time the bottom end has been opened. 

 

Share this post


Link to post
Share on other sites

Go slow. Set the collet as deep and tight as possible. Give it a few taps and then reset it. Repeat this process until you can get the bearing to move 2mm. The collet will then have enough space to grab the bearing and pull as per normal. 

Share this post


Link to post
Share on other sites

Get a can of computer keyboard duster.  Flip it upside down.  Spray the bearing.  You are basically flash freezing it.  Then on the other side of the engine case heat it with a blowtorch.  Do the heating quickly and then try with a fresh collet with a good lip on it.  Should pop out.

I've been there on that particular bearing before.  It takes a while.

Share this post


Link to post
Share on other sites

Yes I understand exactly what you're saying. I was able to flip the case around and use a screwdriver to pry the 2nd bearing away from its seat about 1mm. Should be enough for the lip of the collet to work as normal. 

I'm still struggling on the 1st bearing. Plenty of space behind the bearing for the collet to catch. I just cant get it to pop out. When I hit the slide hammer hard the collet is able to bend and slip through. Because my collet is a bit too small for this bearing. 

 

I see the motion pro now. Its $31 and like other member mentioned would need an adapter to use with my slide. 

I was inspecting with a flashlight and pencil eraser. The bearing still rolls. I do see markings on the needles. 

I also see that the bearing has moved about 0.5mm. Might keep trying. About to screw the case to the wood block to get it a little more solid. Then continue with heat and tiny little taps. I'm using the propane mapp mixture and do tiny taps with one hand while applying heat with the other. Eventually I get mad, hit the hammer harder and it pops through the bearing.

Share this post


Link to post
Share on other sites

Just saw the computer duster post. Yes I've tried that as well on a couple of the other bearings. Haven't tried on these little needle. 

How many seconds of upside down spray would you guess? 

I'm worried about shocking the case too much. One time I had the heated case and bearing, with the puller setup having tension, then blasted air. Probably a dumb move but I was getting frustrated. That bearing finally came out with ten thousand tiny taps. 

Share this post


Link to post
Share on other sites

I doubt they were bad since everyone is saying they never replace them. I didn't realize that was the deal. 

This is my first time doing a complete bottom end rebuilt. Plan was to replace every bearing and oil seal for peace of mind. Regardless of how they felt spinning to my non professional fingers. 

Share this post


Link to post
Share on other sites

Got it!! I think the guy who said I was expanding the bearing was onto something there. Since the original collet had such a small beveled edge, I had to really snug down the tool. Which put all that pressure on the needles expanding the bearing.

I cut the tips off my smallest collet and then shaped a bevel edge into the body of the tool. Installed the tool, barely snugged it down, used the torch and started doing the same little taps like I did before. But this time the bearing came out like butter.

I posted a pic of my 3 smallest collets. I had been using the middle size collet. Then sacrificed the smallest size collet for the new tool. Would had preferred to sacrifice a larger collet that I doubt I will ever use but the bodies are too thick. 

Thanks for all the help everyone. 

Somewhat related other question. I'm leaving for a few days is there some concoction of liquid I could soak my cases in to maybe loosen some baked on grease? I plan to use a parts brush and old gasoline at some point. Then rinse with soapy water or simple green. But not sure about simple green and long term exposure. That would be easy as I have a gallon of concentrate. 

20181022_162405.jpg

20181022_162726.jpg

20181017_094409.jpg

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:


×