Author Topic: Main shaft coupling oil seal  (Read 115 times)

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Offline Bynorthsea

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Main shaft coupling oil seal
« on: 14 Jul 2018 at 18:26 »
Dismantling my Dragonfly for the first time I'd appreciate a little advice. Today I separated the crankcase and gearbox, in doing so I stood the assembly on the timing chest to remove the cap heads. When separated there  was oil on the coupling spinner and also on the clutch, presumably residue from the gearbox coming through the felt seal when it was upright! Originally I had not intended to dismantle the coupling end of the gearbox, should I now do so to replace the felt seal or does the presence of the spinner suggest oil does make its way past the bearing anyway?  Thanks

Offline eddie

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Re: Main shaft coupling oil seal
« Reply #1 on: 14 Jul 2018 at 18:40 »
Hi Les,
           There is probably nothing wrong with your gearbox - the mainshaft has a felt seal that keeps back the majority of the oil, but the coupling has a spinner that throws any escaping oil into a trough and a gallery to the front layshaft bearing. This gallery also acts as a breather for the gearbox (as the oil level is well below the layshaft - the larger gears just dip into it). With the gearbox stood on it's front end, the oil simply runs in the reverse direction and escapes into the bellhousing. If you wash the clutch plate in petrol, it should be reusable.

   Regards,
                 Eddie.

Offline Bynorthsea

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Re: Main shaft coupling oil seal
« Reply #2 on: 14 Jul 2018 at 18:50 »
Thanks again