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BSA Top Gear Noise

A.N.Other
Wide Man
Wide Man
Posts: 551
Joined: Tue Feb 16, 2016 12:45 pm
Location: Leeds

Re: BSA Top Gear Noise

Post by A.N.Other »

Does the tone change significantly between pulling and free wheeling?
If so I would suspect lay shaft bearings if your box has such a thing.
Colin,
I may be slow but I’m rough as well !

Geocet
Posts: 14
Joined: Sat Nov 21, 2020 6:23 pm
Location: Addlestone, Surrey, UK

Re: BSA Top Gear Noise

Post by Geocet »

Hi, Big Col.
I didn't notice a significant chage. I suppose the intensity or volume might have, a bit. Layshaft? not sure the preselectors have such a thing, as such. The epicyclic gear trains are configured differently. The top gear, I've read recently, involves a cone clutch somewhere.Maybe it's something to do with that? The other gears are quiet. Worryingly, I might have to remove it to investigate. I didn't need a project.
Cheers.

Brian-H
Very Wise Man
Very Wise Man
Posts: 1095
Joined: Fri Aug 09, 2019 6:04 pm
Location: UK

Re: BSA Top Gear Noise

Post by Brian-H »

Maybe get someone to sit in the passenger seat, record a short journey with sound, then upload to youtube. That way we can hear it - though it might not help of course.

Geocet
Posts: 14
Joined: Sat Nov 21, 2020 6:23 pm
Location: Addlestone, Surrey, UK

Re: BSA Top Gear Noise

Post by Geocet »

Brian,
Someone with a Smart phone and smart enough to upload onto whatever platform. Yes, simple enough, if we have all the links. A good idea, somebody will have heard this noise before, I'm sure. It reminds me of "dry gears". When the gears (1st, 2nd & 3rd) are engaged the ring gear around the planetary train is grabbed by a brake band, this makes the planets orbit within the ring transferring drive via their respective cages to the output (details of which, I'm not sure) disengagement is simply releasing the brake and allowing the torque being applied to the planetary train to disperse through the spinning ring gear. (Am I telling you something you already know?) Top gear is different but I don't yet know how. But it sounded like a ring gear spinning drily. If you know what a straight cut gearbox on a lathe sounds like in "back gear" at a highish speed? Your suggestion is good but I don't know how to do that, either. Yet. Thanks for reading and seeing fit to offer help. If you were nearer I could let you out in it or take you for a run (fully masked and gowned up, of course).
Anyway, the sun is shining.
Best Regards,
George.

Brian-H
Very Wise Man
Very Wise Man
Posts: 1095
Joined: Fri Aug 09, 2019 6:04 pm
Location: UK

Re: BSA Top Gear Noise

Post by Brian-H »

I used to know quite well how these gearboxes work George - but 've mostly forgotten now :?

There's a couple of good manual/description on the FF & gearbox on db18.org site
e.g. this link https://drive.google.com/file/d/0B97JPQARQptCM1R4azhaM21kVUU/view
and this link https://drive.google.com/file/d/0B97JPQARQptCUjR5Y2Z1VTRGVFE/view

Geocet
Posts: 14
Joined: Sat Nov 21, 2020 6:23 pm
Location: Addlestone, Surrey, UK

Re: BSA Top Gear Noise

Post by Geocet »

Thank-you, Brian.
These manuals will be extremely useful. I don't imagine the BSA box being vastly different in principle. I don't really understand why the intermediate speeds should be so quiet and suddenly, when they are all rotating together there is a loud "argument". Does not seem to affect the running but it can't be doing any good. I'll start with the easy stuff. I'll check the oil level.
Thanks, again, that's great.
George.

A.N.Other
Wide Man
Wide Man
Posts: 551
Joined: Tue Feb 16, 2016 12:45 pm
Location: Leeds

Re: BSA Top Gear Noise

Post by A.N.Other »

Sorry George, I have jumped in where I should have not. I know nothing about your type of box and should of kept my gob shut. Sorry I can’t help but I will keep looking with interest and hope the answers come thick and fast.
Colin,
I may be slow but I’m rough as well !

Geocet
Posts: 14
Joined: Sat Nov 21, 2020 6:23 pm
Location: Addlestone, Surrey, UK

Re: BSA Top Gear Noise

Post by Geocet »

Colin,
Any comment is better than being ignored. Even advice like "shove an old pair of tights into it" is better than nothing. I don't have to do it but it's food for thought. Any shot in the dark might lead to the light.
I suspect, although I didn't want a "project", the gearbox will have to come out. The next thing will be trying to determine what the bits ought to look like.
Thanks,
George.

ranald
Helpful Person
Helpful Person
Posts: 485
Joined: Sat Feb 13, 2016 8:21 am
Location: North Wales

Re: BSA Top Gear Noise

Post by ranald »

George, Just thinking outside the box (ha ha). Might it be higher road speed rather than top gear that manifests this noise? Not sure of the BSA set up. My Lanchester has a coupling shaft between FF and gearbox and this shaft has universal joints at both ends each with 4 bearings. If these bearings are in poor shape it will sound rough at speed. Good luck, Ranald

Geocet
Posts: 14
Joined: Sat Nov 21, 2020 6:23 pm
Location: Addlestone, Surrey, UK

Re: BSA Top Gear Noise

Post by Geocet »

Hi, Ranald.
(Was that the name of a welsh king?)
Anyway, No, it is only top gear. The noise stops if I press the gear change pedal, even if I haven't selected another gear. It is either my imagination or it is becoming less.(am I simply getting used to it?) Maybe it is something that has got rusty or corroded through being left idle for so long? I don't think there is a shaft between the FF and the box. In any case, if the UJs were loose or worn I would expect more of a shudder or vibration and it would be in any gear. I think the noise is something to do with the clutch associated with the "top gear" engagement. I might heave the box out or perhaps remove a cover to give access to inspect, if I knew where to look. My brother says, having looked at a Daimler manual, that it's just like a bus & coach gearbox, only smaller. If only he lived nearer! Maybe someone at the Cobham bus museum at Brooklands...........? Many of the London LTs had preselectors.
Keep the thoughts coming, team, I'm all ears.
Thanks,
George.

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