ETZ 250 Engine Re-build!

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Re: ETZ 250 Engine Re-build!

Postby ivor » Sun Nov 12, 2017 2:53 am

Ha ha, no you're both right, it works on plain bushes and probably not much at all on a roller bearing, put it down to a senior moment. Best just get a puller meant for the job, or see if you can make one yourself like I suggested from a heavy duty builder's fixing.
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Re: ETZ 250 Engine Re-build!

Postby AlanJ » Sun Nov 12, 2017 5:44 am

Hi Skyeport,
Did you melt the wax into the centre and then punch it while still soft? While writing this I have just thought in all my years of mucking about with bikes, I have never had to pull a blind hole bearing. There is always the first time for everything. Wish you well Alan.
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Re: ETZ 250 Engine Re-build!

Postby AlanJ » Sun Nov 12, 2017 5:51 am

Hi Ivor,
Good on you, mind you , at 80 yrs you can't have many more senior moments than me. Alan
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Re: ETZ 250 Engine Re-build!

Postby AlanJ » Sun Nov 12, 2017 7:01 am

Hi M,
You mentioned no gasket between crankcase halves. Have a look at my post Anaerobic Multi Gaskets it might be of interest. Alan.
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Re: ETZ 250 Engine Re-build!

Postby ivor » Sun Nov 12, 2017 7:25 am

AlanJ wrote:Hi Ivor,
Good on you, mind you , at 80 yrs you can't have many more senior moments than me. Alan

:lol:
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Re: ETZ 250 Engine Re-build!

Postby Skyeport » Sun Nov 12, 2017 3:21 pm

AlanJ wrote:Hi Skyeport,
Did you melt the wax into the centre and then punch it while still soft? While writing this I have just thought in all my years of mucking about with bikes, I have never had to pull a blind hole bearing. There is always the first time for everything. Wish you well Alan.


It was a while ago, but i think I just shaved the wax into the hole then tamped it down with a wooden drift made to fit into the bearing shaft hole. I found this technique somewhere on the web, can't remember where.
Bearing was starting to make it's way out when I over enthusiastically tapped the drift a bit too hard & popped the case behind the bearing. It's amazing what you can fix with devcon :)
In hind sight, once I got a bit more clearance under the bearing I should have then used the puller.........
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Re: ETZ 250 Engine Re-build!

Postby Blurredman » Wed Nov 15, 2017 11:53 am

Okay guys.

My bearings have arrived, and after a successful cleaning operation on the case halves I am soon prepared to install the new bearings.

However I have noticed that the replacement main crnak bearings (set purchased from Ost2rad) are open sided on both sides, when the original bearings had open side on teh oil seal only?


Even the official engine dismantling video on youtube uses bearings with one side closed. Also refering to it with "make sure the closed side of the bearing is facing the crank".


I have also posted this to the chaps on the MZ Facebook groups, they all seem to have a mixed response.
1979 Suzuki TS185ER - 9,00 miles - Mud :)
1981 Honda CX500B - 77,000 miles - Long Distance :)
1987 MZ ETZ300 - 29,000 miles - Sun :)
1990 MZ ETZ251 - 39,000 miles - Commute :)

ftp://blurredmanswebsite.ddns.net/Vehicle_Documents/MZ_Documents/
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Re: ETZ 250 Engine Re-build!

Postby AlanJ » Sat Nov 18, 2017 5:08 am

Hi M,
Just to put my pennoth in. Most companies will look at cost saving and as it will cost more to put that shield on a bearing if it wasn't necessary then I don't think it would be there, Just a thought if the shields are not on the crank bearings, what about the loss of pressure in the flywheel area. It's not my field so just a thought.
Wish you well Alan.
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Re: ETZ 250 Engine Re-build!

Postby AlanJ » Sun Nov 19, 2017 4:26 am

Hi M,
I meant to ask earlier, How did you get the blind hole bearing out? Alan.
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