Author Topic: Layshaft Repair  (Read 2017 times)

Offline hd_lonewolf

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Layshaft Repair
« on: 12.06. 2009 18:18 »
I have an A10 STD transmission I plan to use on a bobber project.  After opening the box I discovered that both ends of the layshaft were worn and the bronze bushings were shot.  I'm thinking of replacing the bushings with needle bearings.  What is the best/least expensive way to repair this box?  If you have part numbers please let me know.

Thanks

Offline riflegreen

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Re: Layshaft Repair
« Reply #1 on: 12.06. 2009 19:21 »
Hi Lonewolf ,

The best option in to get the L/shaft ground undersize and have new bushes made .

The needle roller shaft is a slightly different diameter at the ends to the standard shaft plus you would need to have the main case machined to allow for the shim between the shaft & the roller bearing .

Other way is a new layshaft and new bushes .

Chris

Offline trevinoz

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Re: Layshaft Repair
« Reply #2 on: 14.06. 2009 05:03 »
G'day, Lonewolf,
                        I have in the past had the layshaft journals ground, hard chromed and ground to original size.
You can then use standard bushes.
I had a some done a few years ago and they are in service and working fine.
Trev.

Offline cosmikdebriis

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Re: Layshaft Repair
« Reply #3 on: 24.04. 2012 13:29 »
I have a similar problem but was considering getting the end of the shaft ground down to 14mm then machine out the original bush to 22mm leaving a couple of mm in the bush to accept a 14X22 needle roller. The roller will run directly on the shaft but presumably that's already hardened. I will be able to use the original flange on the bush to stop end float of the shaft (though I may add a thrust washer).

Anybody done this, or have an opinion?

I can machine the bush myself so the only things I will have to pay for are the grinding of the shaft and the needle roller(s) (£2.50 ea). Which must be cheaper and better than making a new bush ????

Offline chaterlea25

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Re: Layshaft Repair
« Reply #4 on: 24.04. 2012 21:18 »
Hi Cosmic,
The layshafts  are soft enough to turn with a carbide/ceramic tool
I dont know off the top of my head how much will be removed if you reduce to 14mm
But I rekon that you will have gone through the hardening reducing the shaft by more than 1mm

BSA also used "full compliment " roller bearings for their gearbox bearings (Triumph too!!)
I wonder if you can buy these for £2.50??

Normally I turn the shafts until they are clean -10/15 thou and make bushes to suit
It'l be someone elses problem in another 60 years  ;)

Cheers
John O R
1961 Super Rocket
1963 RGS (ongoing)

Online KiwiGF

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Re: Layshaft Repair
« Reply #5 on: 24.04. 2012 23:33 »
I have same issue but am getting undersize bushes made

I did not ask for a quote but considered buying a new shaft from this company as ot might have been cheaper than getting the machining done, anyone got a price from them for a layshaft?

RandN engineering beckley hill 01474 823771

They have an ad in the VMCC uk monthly mag for gold star gearbox parts

New Zealand

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Offline cosmikdebriis

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Re: Layshaft Repair
« Reply #6 on: 24.04. 2012 23:38 »
Cheers John. Funny how we keep meeting on different forums  *smile*

Anyway, I must admit to having got my dimensions wrong, perhaps getting confused with the GTP project. I think it's a 16mm ID bearing I need rather than 14mm.

Anyway, I need to loose about a mm on the shaft to clean it up so I've given it to my engineering guy with the instructions to clean it up and finish it to a suitable bearing, metric or imperial, whichever gives me the largest diameter.

I'll then make something up to fit the case. Looks like I may need to take the case out very slightly but hopefully not much.

I really should make up some sort of rotating grinding wheel attachment for the cross slide. Shouldn't be too difficult.