Author Topic: A10 engine noise  (Read 3330 times)

Offline Pecon

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A10 engine noise
« on: 30.05. 2012 17:43 »
Hi

 As a new member I am hoping for some advice on an engine noise I have. I recently bought a 1955 A10 plunger from a friend (My first BSA) and it is in almost daily use. I fitted a handlebar fairing but had to remove it due to a huge increase in noise from the engine. (it was so loud that I had to wear ear plugs..!!). The noise is a rumble and seems low in the engine. It does not increase greatly in volume when the revs are increased. I know that it would probably take an engine strip down to find the source of the problem but if there are any known faults that might be a starting point.

 The bike is running well when warm and without the fairing the noise is not too noticeable. The engine number is BA10-12065. (Forgive my ignorance but am I correct in thinking that this is a long stroke engine?) the frame number is BA7S-16217 (Could the bike have started life as an A7?)

 The noise is still there when the clutch is engaged and I have re-greased the wheel bearings as part of routine maintainance.

Any advice would be greatfully accepted,

Peter

Offline Goldy

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Re: A10 engine noise
« Reply #1 on: 30.05. 2012 18:01 »
One of the problems which gives that type of noise is a worn timing side bush. The crankshaft has a bearing on the drive side, but a plain bronze bush on the timing side. If you remove the outer timing side cover, you will see the end of the crankshaft passing through the timing side bush to the oil pump drive. If there is any appreciable wear you will be able to lift the crankshaft with a pinch bar. You need to build something up at the side (stack of bricks or timber etc) to the same level to bar against. I know it works because I have done it, as you lever up you will see any movement within the bush. all the best Goldy
56 A10 Golden Flash - Restore, ride, relive.                                          
56 C12 BSA project ongoing

Offline duTch

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Re: A10 engine noise
« Reply #2 on: 30.05. 2012 19:37 »
G'day Pete, I think all frames were stamped 'A7', up until the later A10 swing arm frames. A7 'S' denotes spring frame, as option to rigid.Good luck with the mains. Cheers, duTch
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 Beezageezauk

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Re: A10 engine noise
« Reply #3 on: 30.05. 2012 19:45 »
Hello Peter and welcome to our friendly forum.

In answer to the second part of your question.  All A7's and A10's shared the same frame and all the frame numbers started with *A7 as a prefix so your A10 would have been in an A7 numbered frame when it left the factory.

There are a couple of exceptions to this rule and there were a couple of A10 models that used an A10 frame number.   The * would be a different letter and would denote the year that the frame was made. For example:-

XA7     1947
YA7     1948
ZA7     1949 to 1952
BA7     1953 to 1957

The "S" after A7 signifies a plunger (sprung) frame.

Beezageezauk.

Offline Pecon

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Re: A10 engine noise
« Reply #4 on: 30.05. 2012 21:28 »

Thanks for the information on the frames guys, it is a relief to know that the frame and engine probably started life as one unit.

Goldie, I had some worries when I saw that SRM do a modified bearing assembly, never a good sign  *sad2*. Is this a job for the home mechanic or will it need an engineering works to sort. How much of a strip down would be required to replace the bush if this is indeed the problem.

 Any thoughts on the engine itself, long or short stroke?.

Cheers,

Peter

Offline Goldy

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Re: A10 engine noise
« Reply #5 on: 30.05. 2012 22:04 »
If you do a search on the forum for timing side bush you will find lots about it. It's a complete engine strip and a new undersized bush needs to be fitted which is then inline bored by a machine shop. But see if there's any movement in it first.
56 A10 Golden Flash - Restore, ride, relive.                                          
56 C12 BSA project ongoing

Online trevinoz

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Re: A10 engine noise
« Reply #6 on: 30.05. 2012 22:18 »
Peter,
              All A10 engines have the same stroke so there is no long or short.
Long stroke only applies to the early A7 engines, Xa7,Ya7,Za7.
Rumbling could also be the drive side main.
Any idea how long since the engine was overhauled?

  Trev.

Offline Pecon

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Re: A10 engine noise
« Reply #7 on: 31.05. 2012 15:54 »
Goldie

   I was afraid of that, I'm not sure what the engineering situation is here in Ireland as it is 40 years since I had cause to use their services. I suspect that few will have any experience in classic machinery. If there is a problem it may mean shipping the bits off to the UK which is going to get expensive.  I'll wait to see if there is any play before going off half cocked.

 Trev.

   The Bike came to Ireland in 2009 and while I have receipts for work done before that it is all cosmetic stuff like electrical, wheels etc. No Idea of what, if anything, was done to the engine. I will try to trace the previous owners and see if I can get any information.

Thanks again,

Peter

Offline Topdad

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Re: A10 engine noise
« Reply #8 on: 31.05. 2012 17:54 »
Peter, re the engineering companies over there , one of the most knowledgeable guys on this forum is based over there , john , aka chaterlea I think, very clued up about A10's and where to get things done ,I'm sure He'll respond to this post but you can find him in many old posts particularly concerning engines, i'll try and PM him for you best of luck BoBH ps he's around cork .
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Offline Topdad

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Re: A10 engine noise
« Reply #9 on: 31.05. 2012 18:01 »
Hi again it's charterlea25 and I've pm'edhim for you Bob.
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Offline Pecon

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Re: A10 engine noise
« Reply #10 on: 31.05. 2012 23:23 »
Bob
 
  Thanks for mentioning John, in fact I had thought of him as I met him at a show here in Dublin and have his card. I tried to ring him but from the ring tone he is out of the country at present. I'll try again next week.

Peter

Offline Clive54bsa

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Re: A10 engine noise
« Reply #11 on: 01.06. 2012 04:07 »
Whoa, slow down mate, 15years ago I bought a Super Rocket with a rumble coming from the bottom of the engine, I too had heard of the timing side bushing problem, so long story short, and $2000 later the problem turned out to be worn splines on the drive side of the crankshaft, the drive gear on the primary side rides on a sleeve that meshes with the crank on splines. So before you do anything rash and spendy, check to see if there is much play in that sleeve to the crank. I fixed mine by taking some 6 thou shim stock, cutting it into strips and sliding them in between the splines, no noise now or the subsequent 22,000 miles since. However "Goldy has a good suggestion on checking the up and down play on the crank. I'm not putting down the SRM conversion, I did it and now glad I did, but it wasn't necessary in my case, a regular plain bushing works just fine as long as you change oil regularly, and are not racing the bike. Good luck with your motor.


'54 GF,  '61 SR,  '71 B50MX

Online chaterlea25

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Re: A10 engine noise
« Reply #12 on: 01.06. 2012 21:07 »
Hi Peter, Bob and All
Peter is correct recognising the out of country ring on the phone
I'm just back from a much needed sunshine break in Portugal,  *smile*
Usual complaints of too much sunshine , beer and food LOL *smile* *smile* *smile*

Peter , phone me when you read this message or early next week, I met so many people at the Dublin event you will have to re introduce yourself  ????
If I can help or advise no problem
Regards
John O R
1961 Super Rocket
1963 RGS (ongoing)

Offline Pecon

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Re: A10 engine noise
« Reply #13 on: 04.06. 2012 22:25 »
Well it looks as though Goldy has called it. I tried the shaft and there is indeed a lot of play. I did manage to make contact with John and hopefully I will get something sorted soon. Thanks to everybody who replied.

Peter

Offline peter

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Re: A10 engine noise
« Reply #14 on: 13.06. 2012 20:18 »
Hello Peter,
I wish you all the best with your BSA A10.The AJS from you is still under construction. I have it completely dismantled,I think it will be ready by january.
Peter
1956 Royal Enfield Bullet 350
1956 AJS 18s
1949 Royal Enfield 500 J2
1954 Golden Flash 650
1985 Virago V1000
2001 Wildstar V1600
1966 Velosolex 50
1999 Virago XV 1100
2012 Kawasaki W800
2016 KTM Duke 390