Author Topic: A7ss engine clatter  (Read 1223 times)

Offline cableguide

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A7ss engine clatter
« on: 31.08. 2012 17:07 »
Hi everyone,

New poster here and long time old biker who's in desperate need of help. Great site by the way..

I rebuilt a 1960 A7SS several years ago, new everything with close attention given to fits where ever possible especially the crank end play etc etc but the thing is there has always been a horrible clatter coming from the engine.

Ive heard this racket on other A series bikes Ive been near,  and Ive also heard bikes which sound smooth and quiet so somethings not right Im sure.

The only thing I can think of which can't be repaired etc is the running fit of the followers in the barrel tubes which definitely had a bit of slop in them, but is this enough to create such a din!

Best I can say is that it does seem to emanate from the barrel area, but the bike doesnt smoke at all and I'm positive the pistons are a correct fit in the bores.  

One thing I have noticed over the years is that the iron head models never appear to have this noise, it always seems to be a bugbear of the alloy head bikes.

All thoughts most appreciated

CG

Online chaterlea25

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Re: A7ss engine clatter
« Reply #1 on: 31.08. 2012 21:42 »
Hi CG,
Welcome to the mad world of BSA's  LOL

I know what you mean when you say you hear the clattering from alloy headed A's
I think that the alloy head apmlifies the general goings on inside the engine (resonance)
On a lot of bikes with alloy heads/barrels the fins are damped with rubber blocks betweenthe fins or tubes through drilled holes in the fins
I have an Ariel with all alloy engine, it sounds like a bag of nails  *eek*
I know theres absolutely nothing wrong with it, same with my A10SR

Earplugs or louder exhaust seems to be the only cure LOL *smile* *smile* *smile*

Cheers
John
1961 Super Rocket
1963 RGS (ongoing)

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Re: A7ss engine clatter
« Reply #2 on: 31.08. 2012 22:16 »
 G'day CG,
              I replied to your post but can't see it. Found it in my history http://www.a7a10.net/forum/index.php/topic,6063.0/topicseen.html
Is it me or this bloody nerd box or firefox.
Anyway I agree John about alloy magnifying noises.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Online chaterlea25

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Re: A7ss engine clatter
« Reply #3 on: 31.08. 2012 22:27 »
Hi Musky
My reply dissapeared as well  *conf* *conf* for a while???
I went back to find and try and repost it, only for the forum to say its been posted already????
Cyberspace my ar**!!

Cheers
John
1961 Super Rocket
1963 RGS (ongoing)

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Re: A7ss engine clatter
« Reply #4 on: 01.09. 2012 05:47 »
Yep there is two topics running in parrallel  http://www.a7a10.net/forum/index.php?topic=6063.new;topicseen#new
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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Muskys Plunger A7

Online Rookie_V#60

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Re: A7ss engine clatter
« Reply #5 on: 02.09. 2012 15:35 »
Hi,
I have a similar problem. Here some recording of the noise:

http://www.youtube.com/watch?v=4nmUH6xnQpA&feature=youtu.be

The engine has good power, starts good, made a 300 mls run without problems, noise is not louder when hot,....

What is it? Piston clatter, cam/tappets, timing gear, big end, primary chain?

Rudolf
1923 James Model 12 500ccm v-twin
1926 Douglas EW 350ccm flat-twin
1936 Motosacoche 500ccm single
1948 BSA A7 Longstroke 500ccm parallel-twin
1955 Ariel Square Four MKII
1960 C1, 1967 C2, 1979 C3-gone!

Online RichardL

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Re: A7ss engine clatter
« Reply #6 on: 02.09. 2012 16:57 »
I think it is important to more accurately locate where, in the engine, noises come from. Just listening while kneeling at the side can give displaced or vague origins. One should use some kind of probe to act like a stethascope. I use an 18" socket extension. Sound loss in the length of this hardened steel will be insignificant. I put one end of the probe to my ear by placing it against the tragus (see the picture) to close that ear against other sound. I use a finger to close the other ear. Doing this, you will start to get a good feel for what sounds are cause by the metals and explosions relative to a given place on the engine.

Once you have a better idea of the location of the source, diagnosis gets a lot easier.

Richard L.
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Offline cableguide

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Re: A7ss engine clatter
« Reply #7 on: 02.09. 2012 18:19 »
John,
Appreciate ur thoughts. Do you know where we can get the rubber inserts that you have mentioned. Cant help but think they might be a good idea.
cg

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Re: A7ss engine clatter
« Reply #8 on: 02.09. 2012 19:12 »
Richard,
I used already a stethoscope to locate,... all I can say like CG is... that it does seem to emanate from the barrel area,...  *conf*
Rudolf

1923 James Model 12 500ccm v-twin
1926 Douglas EW 350ccm flat-twin
1936 Motosacoche 500ccm single
1948 BSA A7 Longstroke 500ccm parallel-twin
1955 Ariel Square Four MKII
1960 C1, 1967 C2, 1979 C3-gone!

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Re: A7ss engine clatter
« Reply #9 on: 03.09. 2012 21:17 »
HI cg,
I have never thought about retro fitting  the inserts  ????
I would have a look for some at a bike breakers ?? I have never seen them for sale as a separate part!!
Today I noticed them fitted to a Tri T140 thats in for sorting

HTH
John
1961 Super Rocket
1963 RGS (ongoing)

Offline BSA_54A10

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Re: A7ss engine clatter
« Reply #10 on: 04.09. 2012 11:52 »
Old "smartie" type clutch cush drive rubbers will work really well.
Old bike workshops should have buckets of them.
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Trevor

Offline Topdad

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Re: A7ss engine clatter
« Reply #11 on: 04.09. 2012 13:48 »
Hi CG, my first solo "A" was an A7SS it didn't smoke but did rattle a fair bit when checked out/cured it turned out to be valve guides , when cold seemed okay but as soon as it warmed up they fell out ,I'd had they changed when I got it and the engineering shop had machined 'em to loose ,a friend who knew his stuff made o/s one's to fit cured in one go and really a quiet engine from then on until it was nicked , BobH.
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