Author Topic: A7 Bottom End Refurbishment  (Read 574 times)

Offline Wayno

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A7 Bottom End Refurbishment
« on: 30.06. 2018 09:45 »
Hi everyone, this is my first time on the forum so greetings all.

I’m in the process of refurbishing the engine on my 1950 A7 short-stroke (one of the early ones) and I need to find a reputable
machine specialist to do the boring of the gear-side bush and regrind the crank.  The top end is fine. 
I have seen a guy called ‘ADE’ of AG Engineering on YouTube installing and boring the gear side bush on an A7
engine (strange coincidence). He was very meticulous and I was very impressed with the quality and accuracy of his work.
 
I was hoping to contact him to see if he would repeat the process on my old engine but I can find no contact details.
Does anyone out there know of ADE or how to contact him?  I believe he is based in the midlands area.
Failing that, can anyone recommend a really good machine specialist who could do the work.

Wayno     

Offline BSA500

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Re: A7 Bottom End Refurbishment
« Reply #1 on: 30.06. 2018 11:53 »
Where are you based?

Offline Wayno

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Re: A7 Bottom End Refurbishment
« Reply #2 on: 30.06. 2018 12:07 »
Oh Yeah, that would help - doh!!
I'm just south of Gloucester but happy to travel a reasonable distance to get a good job done.
Good alignment of the crank with the bearing and the bush is the start of a good rebuild.

Thanks
Wayno

Offline BSA500

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Re: A7 Bottom End Refurbishment
« Reply #3 on: 30.06. 2018 12:19 »
SRM in Wales a lot of people rate their work highly.

Online muskrat

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Re: A7 Bottom End Refurbishment
« Reply #4 on: 30.06. 2018 21:44 »
G'day Wayno.
I did my own pretty much as that youtube video. Took 4 hours to set up exactly right and two minutes to take the cut! Did the roller conversion the same way.
SRM would be my choice as well.
Cheers
An Intro would be nice! Over in https://www.a7a10.net/forum/index.php?board=13.0
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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Muskys Plunger A7

Offline Wayno

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Re: A7 Bottom End Refurbishment
« Reply #5 on: 01.07. 2018 09:07 »
SRM in Wales a lot of people rate their work highly.
I had forgotten about SRM, thanks for the reminding me.  Unless something closer to home is recommended I will contact them.
I still need a short stroke crankshaft before ready for machine work as mine has now had three regrinds on big-end journals and two on main journal.
I don't think I can risk taking it down anymore.

Offline Wayno

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Re: A7 Bottom End Refurbishment
« Reply #6 on: 01.07. 2018 09:14 »
Hello Again, I didn't realise the intro page existed.  I will add some details asap.

Offline BSA500

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Re: A7 Bottom End Refurbishment
« Reply #7 on: 01.07. 2018 10:51 »
Can't you get -40 Big end ahells

Offline duTch

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Re: A7 Bottom End Refurbishment
« Reply #8 on: 01.07. 2018 11:02 »

 Hiya Wayno, if you're not already aware with the T/S bush, is best to just machine it round and bore the next undersize bush to suit... saves unnecessary loss of material
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
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Offline Wayno

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Re: A7 Bottom End Refurbishment
« Reply #9 on: 01.07. 2018 20:18 »
Thing is I don't know how many regrinds one can make on a crank without weakening it.  I have no experience of this.
Service Sheet 207 details three regrinds to big ends and one to main journal.
I probably could get -40 shells and just take enough off the main journal to match new bush but what is the "don't reduce beyond dimensions??"

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Re: A7 Bottom End Refurbishment
« Reply #10 on: 01.07. 2018 20:55 »
G'day Wayno.
All the A7 short stroke cranks are small journal and never went to the large journal like the A10. So the bare minimum should be taken off the T/S journal (as duTch said) and -40 would be the absolute max off the crank pins. And make sure all grinding is done with a 0.090" radius. Also check the bore in the case (for the bush), some have found it to be out of round. In which case a new bush with a larger od will need to be made.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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Muskys Plunger A7

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Re: A7 Bottom End Refurbishment
« Reply #11 on: 02.07. 2018 08:03 »
There is also Hamlins of Bridgewater that would be a bit closer for you. I have not used them myself but have heard they are good. The chap I would have recommended, Gary Bowden of Patchway Bristol, has retired so I also need to look for a new company when I next need a job done.

http://hamlinsengineering.co.uk/
1937 Panther M100 Rigid, 1946 Ariel Square 4, 1952 Norton Model 7, 1953 BSA A10SF (WIP), 1954 Ariel VH, 1961 Triumph T120R

Offline Wayno

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Re: A7 Bottom End Refurbishment
« Reply #12 on: 02.07. 2018 10:25 »
There is also Hamlins of Bridgewater that would be a bit closer for you. I have not used them myself but have heard they are good. The chap I would have recommended, Gary Bowden of Patchway Bristol, has retired so I also need to look for a new company when I next need a job done.

http://hamlinsengineering.co.uk/
Thanks for that, funnily enough Gary Bowden did the previous work on my engine but as you say he has retired now.
There is another guy Steve Riley of PISTONBROKE down in Bristol who I've heard is very good but I will consider Hamlins too .

Thank you all for your help and advice.  I think I will search around for another crank that's had less regrinds than mine.
Failing that I will use my own for one last time.  I understand what you both mean about taking the minimum off the main journal and bore the bush to suit.
One final point - I know someone that has had dealings in building up material on industrial pump shafts.
I need to find out more but I think there is a process of spraying on metal so it can be ground back to the original size.
Has anyone had experience of this?  How strong is the material?
Maybe I could get my crank journals built up and go back to standard size!!
Any comments on this would be appreciated.

Offline duTch

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Re: A7 Bottom End Refurbishment
« Reply #13 on: 02.07. 2018 10:36 »

 
Quote
...One final point - I know someone that has had dealings in building up material on industrial pump shafts.
I need to find out more but I think there is a process of spraying on metal so it can be ground back to the original size.
Has anyone had experience of this?  How strong is the material?
Maybe I could get my crank journals built up and go back to standard size!!
Any comments on this would be appreciated.

 Wayno- that's been discussed on here a few times in depth- but we're always open to new proven and worthwhile developments...if you find any...
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 bikerjohndavies

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Re: A7 Bottom End Refurbishment
« Reply #14 on: 02.07. 2018 21:48 »
Hi, a friend has tried to use Steve Riley recently but he is really under the cosh with jobs coming in since Gary and a couple of other local engineers retired so has a large work load and could take quiet a while. Best to check with him how long it might take before giving him the job.
1937 Panther M100 Rigid, 1946 Ariel Square 4, 1952 Norton Model 7, 1953 BSA A10SF (WIP), 1954 Ariel VH, 1961 Triumph T120R