Author Topic: Gearbox overhaul  (Read 691 times)

Offline ADP91

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Gearbox overhaul
« on: 10.07. 2015 21:03 »
Hi everyone,

Just picked up my swingarm a10 gearbox and I'm in the process of making a list of parts to order for an overhaul. What parts should I be looking to replace? I'm assuming gaskets, seals, and bushings but are there any other wearable parts that I should be aware of?

Cheers

Online chaterlea25

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Re: Gearbox overhaul
« Reply #1 on: 10.07. 2015 23:35 »
`Hi,
If the gearbox came from an A10 then usually theres wear on the layshaft where it runs in the case bushes
The shaft can be machined or ground undersize and bushes made to suit.
Look for wear on the gear  engagement  dogs,
Quite often the final reduction gears at the inner end of the box will have wear on the gear teeth
Look for wear or pitting on all gear teeth
Check for wear on the selector forks and camplate,
Usually the kickstart quadrant and ratchet gear will be worn
Its good practice to replce the gearchange return spring/ kickstart spring, but not essential
The clutch arm pivot can often need bushing as the case wears

HTH
John
1961 Super Rocket
1963 RGS (ongoing)

Online KiwiGF

  • Last had an A10 in 1976, in 2011 it was time for my 2nd one. It was the project from HELL (but I learned a lot....)
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Re: Gearbox overhaul
« Reply #2 on: 11.07. 2015 01:28 »
The sleeve gear bushes are often worn....you can check for this by seeing if the final drive sprocket has up and down play....they are not expensive but need honing to size after fitting.

Edit: not the sprocket but the shaft....see below....

You might want to replace the ball bearings on the main shaft and lay shaft whilst you are doing the job.

Best thing is dismantle and inspect and then make your list up?
New Zealand

1956 A10 Golden Flash EA7-168x, CA10 913x, left BSA together for Liverpool, 5th Dec 1955.

1949 B31 rigid “400cc hot rod” (favourite bike)

1949 C11 rigid, but why!!! (cos it was cheap)

1937 B21, missing parts so mission impossible?

1952 Armstrong Siddeley Whitley for rainy days (with wife).

GL1800 Goldwing not sure why, maybe cos it always starts

Offline duTch

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Re: Gearbox overhaul
« Reply #3 on: 11.07. 2015 03:26 »

  *????*
Quote
The sleeve gear bushes are often worn....you can check for this by seeing if the final drive sprocket has up and down play...
*????*
 Am I missing something, or did you mean the clutch end of the mainshaft...?

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 KiwiGF

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Re: Gearbox overhaul
« Reply #4 on: 11.07. 2015 07:30 »
Dutch you are right I meant the play will be felt in the main shaft not sprocket  *doh* *problem* *dunno2*

Oh, and the oil seal on drive side of the main shaft will probably need replacing....
New Zealand

1956 A10 Golden Flash EA7-168x, CA10 913x, left BSA together for Liverpool, 5th Dec 1955.

1949 B31 rigid “400cc hot rod” (favourite bike)

1949 C11 rigid, but why!!! (cos it was cheap)

1937 B21, missing parts so mission impossible?

1952 Armstrong Siddeley Whitley for rainy days (with wife).

GL1800 Goldwing not sure why, maybe cos it always starts

Offline Rocket Racer

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Re: Gearbox overhaul
« Reply #5 on: 11.07. 2015 23:44 »
I'm just refreshing an SC box and the sleeve gear bushes were really bad. And has the usual layshaft wear issues.
The Kickstart gear on the end of the mainshaft are also often clearly visually worn but readily available. Bit hard to miss the wear on that.
If the dogs are pitted you will typically find gear noise when riding. These boxes are pretty robust and foolproof  *whistle*.
Replace the sleeve gear seal and the natural time to review the final drive sprocket
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
New Zealand