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Post by jacques on Jun 23, 2011 20:26:30 GMT
Two part bearings....Great while you have them on your crank (Sorry, I still prefer a single bearing! ;D), but rather difficult to get off the crank shaft or out of the engine casing if you need to change bearings! I had to get the an outer bearing race out of the flyside crank housing today and no amount of heat would shift the thing. So I welded a piece of steel rod to the race, gently put some heat into the casing and drifted the bugger out! Clean and degrease the bearing and give it a light sanding. Next cut some steel rod and chamfer the edges to get more weld area.  You have to be careful not to put too much heat into the race otherwise you may melt the casing. It's best to weld in the middle of the race where it's thickest.  Heat the casing around the bearing housing, turn the casing so the stator surface is facing up and tap the bearing race out!   (Don't ask me how to get the half on the crank off...I just bought a new crank!  ) |
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Post by nicsar on Jun 23, 2011 21:06:26 GMT
To remove the bearing race from the crank I find this handy.  together with this  First I use the angle grinder to cut slots in the race to make it easier for the puller to grab, then just pull it off. When the race is in the casing I found some nice washers that sit tight in the race, I weld a few spots on the race to anchor the washer, then just hit it out. |
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Post by tony on Jun 23, 2011 22:30:18 GMT
Thats a lot of work fella! Tbh I normally just heat them with a butane or propane torch... at a given point the expansion rate will let them drop out. I have never had them float and therefore drop out at 80c (sorry mathias  ) as the interference fit is usually too tight...but they will drop out at higher temps. If they dont the bearing may of been loctited in.. but this will break down with temperature. Another way us to cut some slots in with a dremel type tool to get a punch to gain a purchase. Use heat and then knock out. |
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Post by madmax on Jun 24, 2011 5:44:20 GMT
I use a butane/propane blow torch too and never had any problems.
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Post by amazombi on Jun 24, 2011 10:32:08 GMT
.. at a given point the expansion rate will let them drop out. I have never had them float and therefore drop out at 80c (sorry mathias ) Rest assured, you have driven home the point that you were, and apparently are, still blissfully ignorant of what a floating fit actually is quite securely. Aren't you even tempted to pick up a book, or if that's not your cup of tea, have a close look at different engines every now and then? |
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Post by tony on Jun 24, 2011 17:05:01 GMT
mate... get a sense of humour... I know all about expansion rates.  |
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Post by tony on Jun 24, 2011 17:12:00 GMT
Here are Mathius... this backs up what you are saying. www.maintenanceresources.com/referencelibrary/bearings/rbshf.htmHowever if the bearing is not fitted correctly with NO load as I was saying in the first place it will fail. Gilera runners are quite prone to this. That was my point in our earlier discussion. I understand what you are saying.. yes.. thats fine but you have to bolt up drive side first to make sure its not loading the bearing. |
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Post by jacques on Jun 24, 2011 17:14:55 GMT
Sorry, my bearing race was stuck solid...I had a torch on it for a good 10 mins, turned it upside down and banged the casing on some wood...No go..When I took it out there was thick, solid brown muck on the bottom of the race. The engine had suffered from a seize before, I can't even scrape the stuff from the bearing race! |
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Post by amazombi on Jun 25, 2011 18:13:47 GMT
mate... get a sense of humour... I know all about expansion rates. I'm German. That would be rather a contradiction in itself. Still if you keep repeating that most excellent joke of yours not all may be lost and I might even understand it some day. What's a Gilera Runner? I don't think I'm familiar with that. @jaques: That strange gunk you now have on your bearing race is likely to be burnt oil/grease. It probably now has a glossy look and is rather brittle. I think the idea with welding in a bar to have something to apply force against is a good idea. If you don't have access to a welder you could also use a Dremel with a disc to cut slots in the same plane as the bearing. You could then use a punch and a hammer to get it out. |
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Post by jacques on Jun 25, 2011 18:54:24 GMT
Yep, almost like black glass!  |
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Post by hank on Jun 30, 2011 11:09:49 GMT
If you don't have access to a welder you could also use a Dremel with a disc to cut slots in the same plane as the bearing. You could then use a punch and a hammer to get it out. I've done that a couple of times, prob the best solution for those of us with no welding skills! |
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Post by firej on Jul 11, 2011 3:43:42 GMT
they make a adjustable inter bearing tool for taking that out has two thin hooks that lift it out , you should of stuck it in the freezer it would of fallen right out
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Post by smallframetony on Mar 12, 2012 1:02:37 GMT
on my pk engine the bearing come out with the crank... i think  I dont remember having trouble getting it out anyways The inner part of the bearing... now what a bastard ! I left it on the crank and just replaced the outer and needle bearings, seems to fit nicely and i have had no problems after 700 miles. I know its not the way to go but i'm still learning |
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Post by smallframescott on Mar 12, 2012 8:09:06 GMT
I put the case in the oven |
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Post by steve67 on Mar 12, 2012 22:49:11 GMT
3 large tacks with the mig on outer race, let it cool and it will shrink the race then warm case and knock out with a hammer and punch, done one on sunday no problem, old trick for getting race off of crank is one large hammer and a vice, and a steady hand, i will let you work it out, done loads no problem.
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Post by smallframetony on Mar 15, 2012 0:01:35 GMT
thanks steve... i'll have a go with an old crank first |
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)
) as the interference fit is usually too tight...but they will drop out at higher temps. If they dont the bearing may of been loctited in.. but this will break down with temperature. 
I dont remember having trouble getting it out anyways 
