Author Topic: 1952 A7 Star twin chain case seal  (Read 454 times)

Offline KeithA

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1952 A7 Star twin chain case seal
« on: 16.11. 2015 12:23 »
With the gearbox main shaft through to the primary chain case, I can see specks of light when closely inspecting the seal with a torch and mirror.
Can I replace the seal from the chain case side, by grinding away the three rivet heads, and removing the oil flinger plate, or will I have to remove the gearbox.
How prone are these seals to leaking.
I'm thinking I can replace the outer ring after I replace the seal, and hold it in place by tapping three holes in the chain case to secure it.
Any thoughts??
Thanks in advance.
Keith A

Offline terryk

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Re: 1952 A7 Star twin chain case seal
« Reply #1 on: 16.11. 2015 16:04 »
there is info here on the forum your question or similar has been asked before.

In short to do it properly you would need to pull the engine and gbox out and do a mod. In saying that you could do it with engine and gbox in and use pop rivets and goo. Also tape the gbox mainshaft and grease the seal over the shaft.

One question though Keith is it leaking very bad? If not leave it till you have to do other repairs but I guess if you can see light you already have the clutch out.
I am working on a set of A10 plunger cases with a large hole machined so the gbox sprocket can be changed without taking the engine out and also this seal can be replaced. I have to machine a plate and fit it in with a cheap and easily obtainable seal. I haven't finished it yet but I don't need it at the moment so one day it will be finished. It's a good modification for these models.
1950-53 A10 rigid/plungers, 1958-61 A10 super rockets, 1947-50 A7 longstrokes, 1949 Star twin,
1951-54 A7 plungers, 1940s M21, WDM20s,
1948-50s B33s rigid/plunger/swingarm, 1948-50s b31s rigid/plunger/swingarm

Online muskrat

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Re: 1952 A7 Star twin chain case seal
« Reply #2 on: 16.11. 2015 18:18 »
I think it was duTch that did a similar mod to his plunger. He'll be up soon.
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Muskys Plunger A7