Author Topic: Gearbox = coffee grinder  (Read 1909 times)

Online RichardL

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Re: Gearbox = coffee grinder
« Reply #45 on: 22.05. 2017 23:38 »
I'm having a bit of trouble understanding this because the picture on the left strikes me as the version WITHOUT a gasket, because the pieces are closer together. What gives?

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020 (if it's not cancelled and we are free to move about by then). Watch website at https://www.gentlemansride.com for details.

Online Greybeard

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Re: Gearbox = coffee grinder
« Reply #46 on: 23.05. 2017 09:10 »
I'm having a bit of trouble understanding this because the picture on the left strikes me as the version WITHOUT a gasket, because the pieces are closer together. What gives?

Richard L.
Yes, I've been trying to rationalise that. I still think the principle of the claw meeting the cam with a very close tolerance yet fully engaging when working properly has to be the explanation.

Online RichardL

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Re: Gearbox = coffee grinder
« Reply #47 on: 23.05. 2017 10:57 »
I've never been inside a plunger gearbox and it's been 10 years since being inside my SA box, so I know next to nothing. With that disclaimer, I can say anything. Maybe the issue is that it was always intended for the claw to be a close fit with the cam, and the cam (or claw) has worn down, requiring the removal of the inner gasket to engage with any regularity at all. I doesn't make sense to me that BSA shows an inner gasket in the parts book, but using it fails the gearbox.

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020 (if it's not cancelled and we are free to move about by then). Watch website at https://www.gentlemansride.com for details.

Online Greybeard

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Re: Gearbox = coffee grinder
« Reply #48 on: 23.05. 2017 12:11 »
...Maybe the issue is that it was always intended for the claw to be a close fit with the cam, and the cam (or claw) has worn down, requiring the removal of the inner gasket to engage with any regularity at all. I doesn't make sense to me that BSA shows an inner gasket in the parts book, but using it fails the gearbox.
This is a rebuilt gearbox so should be good  *conf* . I searched the forum for similar problems and found a few posts referring to the gasket issue. I did some work on the box during the bike rebuild four years ago. I presume that there was no inner gasket when I stripped it so didn't fit one on assembly. Until now I only had a slight problem when the bike was really warmed up; changing gear sometimes required a second dab. Since the recent work all changes are really positive and easy.
Any road up, (as they say somewhere), I'm now a happy Plungy, (thanking duTch for that name) owner  *smile*

Online RichardL

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Re: Gearbox = coffee grinder
« Reply #49 on: 23.05. 2017 13:30 »
... I doesn't make sense to me...

...about sums it up.

Richard
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020 (if it's not cancelled and we are free to move about by then). Watch website at https://www.gentlemansride.com for details.

Online JulianS

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Re: Gearbox = coffee grinder
« Reply #50 on: 23.05. 2017 14:21 »
The available gaskets come in different thicknesses, depending on source.

An original old stock BSA gasket in my gasket folder very thin at about 0.006 inch thick.

A modern paper gasket a bit thicker at about 0.009 inch thick.

A modern composite material gasket much thicker at about 0.018 inch thick.

Offline duTch

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Re: Gearbox = coffee grinder
« Reply #51 on: 23.05. 2017 15:05 »

Quote
...... I'm now a happy Plungy, (thanking duTch for that name) owner  *smile*

 Geez thanks Geebs- I don't remember that, thought it must be one of yours, so was giving you the credit.  *dunno*

 I've pondered the relationship of 'the claw' some time ago, but put it on the back-burner. It may require fabricating a dummy carrier for the camplate to attach to a spare inner biscuit to fully research it....actually.. *bright idea*.. just remembered I did start to do it to check out the selector fork clearance, but been sidetracked with stuff like work...

 One other thing to keep in mind is the end-float of the layshaft with each different gasket thickness
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Online RichardL

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Re: Gearbox = coffee grinder
« Reply #52 on: 23.05. 2017 15:38 »
Is there an opening big enough to fit a flexible boroscope? I ask this recognizing that GB may not give-a-hoot anymore, as he rides smilingly along.

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020 (if it's not cancelled and we are free to move about by then). Watch website at https://www.gentlemansride.com for details.

Online Greybeard

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Re: Gearbox = coffee grinder
« Reply #53 on: 23.05. 2017 15:54 »
...GB may give-a-hoot anymore, as rides smilingly along.
I hope to not have to give-a-hoot during the time I have left to ride my BSA.  ;)