Center web oil seal.

Information relating to the Matchless G9 or AJS Model 20 500cc twin
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RodneyK
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Joined: Thu May 12, 2022 7:43 pm
Location: British Columbia CANADA

Center web oil seal.

Post by RodneyK »

I am just starting the rebuild of a 55G9B that I received already torn down to individual parts. This is my first ever build and thanks to your amazing forum I sourced a center bearing and am about to install the crank.
My question is, how do I seal around the oil passage in the web? There is no recess for an o ring and no gasket in my set. Do I make a paper gasket? It’s mentioned in the manual to watch for one.
If this has already been covered, please pass on the link. I greatly appreciate your advice and will likely be needing much more.
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1608
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Re: Center web oil seal.

Post by 1608 »

As far as I'm aware there is no gasket to do with the centre web. I believe the 'O' ring gasket you refer to is a thin paper one that fits btn the two crankcase halves to seal the oil filter tunnel, often missed! This area is notoriousfor oil leaks and there are several suggestions on how to improve the sealing of this joint. You will need to research the form for these options.
RodneyK
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Joined: Thu May 12, 2022 7:43 pm
Location: British Columbia CANADA

Re: Center web oil seal.

Post by RodneyK »

OK, but my manual states, under Dismantling Engine, Centre Web, “Watch for the paper gasket for sealing the oil passage.” Unfortunately I was not involved with the dismantling, so did not get to see it, and the manual does not mention it again under Re-assembly. I’ve heard that some people machine a recess for an o ring and others just dob a little gasket compound around the hole which is what I will do if I don’t hear from anyone else.
I appreciate your advice on sealing the oil filter tunnel as well. I’ll watch for that. Any and all advice welcome, thank you.
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dave16mct
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Re: Center web oil seal.

Post by dave16mct »

1608 is right, there's no gasket on the centre web oil hole. The gasket referred to in the manual is on the oil filter tunnel.
Dave.
RodneyK
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Joined: Thu May 12, 2022 7:43 pm
Location: British Columbia CANADA

Re: Center web oil seal.

Post by RodneyK »

Thanks so much Dave and 1608. I can now proceed with more confidence.
MalcW
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Location: DEVON UK

Re: Center web oil seal.

Post by MalcW »

dave16mct wrote: Sun Jun 05, 2022 8:56 pm 1608 is right, there's no gasket on the centre web oil hole. The gasket referred to in the manual is on the oil filter tunnel.
Dave.
Thank goodness for that! I've just put a 500 twin back together and thought I might have left something out!

Malc
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