Author Topic: Gearbox Mainshaft Oil seal  (Read 110 times)

Online Nourish

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Gearbox Mainshaft Oil seal
« on: 11.06. 2026 17:19 »
A question about the felt oil seal on the gearbox main shaft behind the clutch. Is it adequate and/or is it possible to replace it with a modern lipped seal?
Long stroke A7

Online Swarfcut

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Re: Gearbox Mainshaft Oil seal
« Reply #1 on: 11.06. 2026 18:24 »
  The original is a fabric composite, and even when new I doubt it could ever be as effective as a modern seal.

 While the case is bare, changing is straightforward. Measure shaft OD, housing ID and seal thickness to find a seal that will fit. No mystery for your local bearing supplier or the usual online suspects.
 This is one of the parts carried over to the later engine, so can be searched under part 67 1242

 Swarfy.

Online muskrat

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Re: Gearbox Mainshaft Oil seal
« Reply #2 on: 11.06. 2026 22:30 »
G'day Nourish.
I replaced mine with a proper seal. Sorry I can't remember the seal number. You have to drill out the rivets of the retainer, measure the hole diameter and thickness and the shaft size. The local bearing shop will have a seal. Replace the retainer with new rivets from the outside in. https://www.a7a10.net/forum/index.php?action=dlattach;topic=16831.0;attach=60782
or here https://www.a7a10.net/forum/index.php?topic=16831.75 page 6 near the bottom. Wow that thread has been read 23 thousand times *eek*
Cheers
'51 A7 plunger, '57 A7SS racer now a A10CR,  '83 CB1100F, 88 HD FXST, 2000 CBR929RR ex Honda Australia Superbike .
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