How to press in crank bearings and clutch bearings without a torch?

francisjohn

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I ain't buying a torch to use it once in my life, or to keep it in my garage for the next three years. The amount of stuff I've accumulated because I "will use it later" has gotten ridiculous and my ol' lady has had enough too :LOL:

I called various shops in my area and no luck.

I have crank bearings that need to get replaced. I ordered a x10 pack of PGN 6202, took an empty 66cc bottom end I have and practiced as it would make sense to replace the clutch bearings while I have the case split.

The clutch bearings is where I'm having some problems, specifically behind the clutch cover. In the case, the bearing sits 4.5mm past the surface (photo below) I can't think of a good way on how to knock it into the case.

The crank bearings were pretty easy as I just used a block of wood.

1) Are the crank bearings supposed to be flush to the case? or do they protrude a bit? If so, how many millimeters?

2) What is the best way to press in bearings without access to a press? Are there any tips or tricks you have?

3) Any tips for getting the bearing in evenly? I've never delt with a bearing this thick (11mm) and on smaller bearings (6002) it was more easy in my opinion.

I did attempt to press the clutch bearings in by using a 1/2 x 6" bolt and making a homemade press. Even with using washers and trying it different ways, it ultimately damaged the bearing (photo below of what sounded like a great idea originally, and now... not so much)
 

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Nickt919

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One option is put the case halves in the oven and freeze the bearings.
A safe temp would be around 250*-275*.
The frozen bearing would probably drop in the hot case or go in with little force.

No beating or homemade press that would put force on the balls or inner race.
 

francisjohn

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Surgery was a success guys. One crank bearing was toast. The bearing under the clutch basket was destroyed. The bearing cage was in pieces, it was loose ball bearings rolling around.

I put the bearings in the freezer, I did not use a torch or heat the case. I found the secret weapon, specifically a 15/16" SAE - Pittsburgh 1/2 drive socket. It has an OD of around 34mm, and sits on the outer race and presses it in and has no contact with the outer race.
 

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Chainlube

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Surgery was a success guys. One crank bearing was toast. The bearing under the clutch basket was destroyed. The bearing cage was in pieces, it was loose ball bearings rolling around.

I put the bearings in the freezer, I did not use a torch or heat the case. I found the secret weapon, specifically a 15/16" SAE - Pittsburgh 1/2 drive socket. It has an OD of around 34mm, and sits on the outer race and presses it in and has no contact with the outer race.
I love happy endings!
 

ImpulseRocket

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Surgery was a success guys. One crank bearing was toast. The bearing under the clutch basket was destroyed. The bearing cage was in pieces, it was loose ball bearings rolling around.

I put the bearings in the freezer, I did not use a torch or heat the case. I found the secret weapon, specifically a 15/16" SAE - Pittsburgh 1/2 drive socket. It has an OD of around 34mm, and sits on the outer race and presses it in and has no contact with the outer race.
That's great news. Alternative to using a torch to heat the cases is to simply stick them in the oven on the lowest heat setting (around 200 degrees) for several minutes. Just make sure the wife ain't home when you go to bake your engine, or that she is cool with it lol.
 

francisjohn

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I love happy endings!
Well, that was short lived.

I have a new issue. I made the crank-case gasket using Fel Pro 3046. The paper is 1/32 thick. I pressed in a new clutch assembly and everything is seated fine (assembly, basket and sprocket) however when I put the clutch cover on, everything rubs. I know it's not the pins because I pressed those in a couple weeks ago when those were rubbing (plus I looked at the basket when I put it back on to see how everything is looking)

I think it might have to do with the crank case gasket. I've heard of this problem happening when people use RTV. I know one person who built a hybrid and had this happen to him as the gasket does help shim it a bit.

That's great news. Alternative to using a torch to heat the cases is to simply stick them in the oven on the lowest heat setting (around 200 degrees) for several minutes. Just make sure the wife ain't home when you go to bake your engine, or that she is cool with it lol.

I didn't use a torch or anything, zero heat. Just froze the bearings and used the socket listed above. I was going to originally, but I put oven mits on to see how hard would it be to hold a socket while the case was hot and realized it was quite the challenge.
 

Nickt919

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You can run 2 cover gaskets to stop the cover rub.
But... IF the center gasket is thicker than usual then you need to check the crank and clutch shafts for in/out.... extra end play.
By making the case wider it can create extra side to side movement on those shafts.
1/32" gasket paper is .79mm.
I' don't know the regular gasket thickness but if it's thinner than .79mm it cannot be by much.

Some engines will come with a shim or 2 on the crank to set this clearance.
IRC,...it's 1mm end play on the crank. I’ve shimmed the crank closer to .5mm on engines and didn’t have any problem … that I knew of.
A certain amount of end play is necessary for expansion.

If this was my issue… as long as both shafts have about 1 mm end play I’d just run a second gasket on the clutch cover to stop the rubbing.
 

Chainlube

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Well, that was short lived.

I think it might have to do with the crank case gasket. I've heard of this problem happening when people use RTV. I know one person who built a hybrid and had this happen to him as the gasket does help shim it a bit.
That sounds like the crank is contacting the bearing. Is there any marks on the inside of the cover? If not, then it looks like you're going back in.
 
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