Author Topic: Swapping gearbox into a new case.  (Read 230 times)

Online Minto

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Swapping gearbox into a new case.
« on: 11.04. 2021 17:44 »
Hello all
I've recently acquired a nice shiny main gearbox case for my plunger A10, along with a new seal from a very helpful bloke called Richard from Atherston.
I'm going to attempt to swap the innards from my own ratty looking case. I've never touched the gearbox before, any advice or potential disasters on the horizon?
The box currently works ok, though is whiney in 3rd and a bit clunky going down from 3rd to 2nd but otherwise fine.
I'm not far off done rebuilding the engine again and as I think the gearbox main oil seal needs changing thought I'll give this a go while it's all out the frame.
Any help or advice welcomed.
Ta
Jase
52 A10 plunger
Aprilia RSVR

Online Greybeard

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Re: Swapping gearbox into a new case.
« Reply #1 on: 11.04. 2021 19:58 »
I've recently acquired a nice shiny main gearbox case for my plunger A10, along with a new seal from a very helpful bloke called Richard from Atherston.
Richard Clamp. Excellent bloke. 👍 I wrote up my experience with him in the 'Services' section a couple of years back.

Offline Sav

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Re: Swapping gearbox into a new case.
« Reply #2 on: 11.04. 2021 20:14 »
"Clunky" could just as easily be a bit of clutch drag.

You will need to check the shafts fit to the bushes carefully.
1961 A10SR, spent a fortune at SRM
1961 A7SS, finally the right green
2011 New addition 1937 Empire Star, twin port, high pipes. Turned out to be the most unreliable bike I have handled.
2017 finally found the liner/barrel were flexing and causing all the overheating/nipping up. Early B33 barrel fitted and it's reliable at last!

Online Minto

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Re: Swapping gearbox into a new case.
« Reply #3 on: 11.04. 2021 21:43 »
I've recently acquired a nice shiny main gearbox case for my plunger A10, along with a new seal from a very helpful bloke called Richard from Atherston.
Richard Clamp. Excellent bloke. 👍 I wrote up my experience with him in the 'Services' section a couple of years back.

Yes indeed, a pleasure to do business with. I haven't completely ruled out giving him the box to do for me.
Jase
52 A10 plunger
Aprilia RSVR

Online Minto

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Re: Swapping gearbox into a new case.
« Reply #4 on: 11.04. 2021 21:51 »
Sav
It's only clunk between 3rd to 2nd but
I've got some new clutch plates to go in so hopefully that'll help.
The case has a new bush fitted, Richard says it should just fit as is.
Cheers
Jase
52 A10 plunger
Aprilia RSVR

Online chaterlea25

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Re: Swapping gearbox into a new case.
« Reply #5 on: 12.04. 2021 21:13 »
Hi Minto,
You will need the check the layshaft where it runs in the bushes,
Almost all will be worn / scored to some degree  *sad2*
On the plunger gearbox selection problems can arise due to slight variations in the position of the inner casing
adding or removing gaskets can help position it correctly
If you have never been inside a gearbox before it might be wise to land the lot back to Richard mentioned above

John
1961 Super Rocket
1963 RGS (ongoing)

Online Minto

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Re: Swapping gearbox into a new case.
« Reply #6 on: 15.04. 2021 01:15 »
Hey John, you may we'll be right, Richard did say however that I should "have a go at it," and "you can't go wrong", and most importantly that "if it all does go wrong I can then hand it over to him". So, as I do enjoy a challenge, I'm in!
Jase
52 A10 plunger
Aprilia RSVR