Author Topic: A10 break down, analysis  (Read 2447 times)

Offline muskrat

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Re: A10 break down, analysis
« Reply #15 on: 28.05. 2017 02:04 »
G'day Anders.
The tick tick coming from the cam area is probably just back lash in the gears. Especially noticeable when turning the motor over by hand or kickstart. If the tappet clearances were ok that would be it.
Definitely piston and or ring trouble giving excessive crank case pressure which would also create the rockerbox leak.
Cheers
'51 A7 plunger, '57 A7SS racer now a A10CR, '78 XT500, '83 CB1100F, 88 HD FXST, 2000 CBR929RR ex Honda Australia Superbike .
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Offline BSAnders52

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Re: A10 break down, analysis
« Reply #16 on: 28.05. 2017 02:24 »
Well, well, well, finally I could not resist the temptation. I cant go on and just ponder and speculate..
 Took off the rockerbox and cylinder head.

Genttlemen, manny of you were very right, and I too had come to have the same suspicions, the main dammage is in the RH cylinder, caused by a loose gudgeon pin! Both circlips seem to have desintegrated and the pin is gnawing a deep gash in both sides of the cylinder.

The entire inner surface of the valve house is covered with a sticky, allmost rubbery deposit, in the push rod shaft it appears like charcoal debris.
I  suspect this is to be found in the entire engine, in all oil ducts and pipes..
Alreaddy this talks for the engine to be split.

And the conrod may be dammaged as well.

I did not continue with lifting the cylinder, the hour is very late, I have found the dammage corresponding to the symptoms, however I have not yet seen it all..

Good night, or rather good morning

Anders
Sweden



Online KiwiGF

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Re: A10 break down, analysis
« Reply #17 on: 28.05. 2017 02:53 »
Hi Anders, yep a top and bottom strip down and clean is needed, and you may as well check the condition of all the various bearings whilst it's in pieces.

It looks like the engine may have been left a very long time without being run. I'm sure someone will now mention the "sludge trap" in the crank ! (Only a small one, in a small journal crank)

Good pics  *beer* but sorry to see the damage   *help*
New Zealand

1956 A10 Golden Flash  (1st finished project)
1949 B31 rigid “400cc”  (2nd finished project)
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Offline muskrat

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Re: A10 break down, analysis
« Reply #18 on: 28.05. 2017 03:13 »
Ouch, yep, that'll do it.
Full strip time. Bore till clean then see what piston size you need.
The rod MIGHT be OK and just need a little end bush. Get them checked and if only the slightest bit out throw them away.
Commiserations.
'51 A7 plunger, '57 A7SS racer now a A10CR, '78 XT500, '83 CB1100F, 88 HD FXST, 2000 CBR929RR ex Honda Australia Superbike .
Australia
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Offline BSAnders52

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Re: A10 break down, analysis
« Reply #19 on: 28.05. 2017 09:47 »
Yes, yes, yes, I am aware I will have to tare it down to the smallest item..
Someone mentioned in an erarlier input, that theese iron headed motors dont need to be specially treated or rebuilt to work with modern un-leaded fuel. Is this correct? Do they not even need lead substitute added? Or did I mis read that?

Beeing without a workshop manual for the moment, what are the different over sizes for pistons/ bore?  Of course they are not in metric millimmeters to start with, but theese cylinders are 71,5 mm = 2,815 ". Is this on the high end or on the lower end of possible over dimensions? I have no idea what size they were 40 years ago, but I cant remember I had it rebored.., I think I had new pistons installed.., aah dont know.

When I restore one of all theese JAWA engines that float through my workshop, I do as a rule replace all bearings, just to know all are new and in the same condition. All clocks are on zero. I guess I ought to keep that habit allso here. It is impossible to determine wich bearings are OK and wich need replacement, apart for those obviously dammaged.
Are all bearings easily obtainable? I know theese imperial measure bearings can be tricky to find..

Is there any other easy improvement that can be done while the engine is anyway taken apart?
Reworked or completely new oil pump is still on the list.
I guess a normal service of the cylinder head will do. And continue with lead -substitute..
Clutch seems to work OK.

Yes, that sludge trap, where is it? Any picture?

Until later

Anders
Sweden



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Re: A10 break down, analysis
« Reply #20 on: 28.05. 2017 10:09 »
It may have been an old circlip re-used or a new one mistreated (bent) or not fully fitted. Or a square-section clip in a round groove.

Or- your bores may not be perpendicular to the barrel base, or the crankcase top face may not be parallel to the crank bearings, or you may have mis-matched crankcase halves, with a step on top, where they meet.

Any of those alignment issues, especially combined with detonation, and/or play in the big ends, can hammer the pin and circlip out.

Offline duTch

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Re: A10 break down, analysis
« Reply #21 on: 28.05. 2017 10:55 »

 Anders, if it's any consolation, it isn't as bad as when mine did the same thing- groove about 1/16" (1.6mm) deep *eek*

 
Quote
what are the different over sizes for pistons/ bore?  Of course they are not in metric millimmeters to start with, but theese cylinders are 71,5 mm = 2,815 ". Is this on the high end or on the lower end of possible over dimensions?

 Standard bore is in fact in metric; 70mm, so 71.5 is 1.5mm O/S, (+0.060") There are apparently +0.080" available, but I'll let someone else butt in on that.

 The bearings (slippers and all Roller/Ball-race bearings)are more available now than in the '70's (I reckon, in my case anyway)- cost a bit more than metric ones though....

 There are cast iron body 'High-flow' oil pumps available at a cheaper price (~GB ?180 ?) than the SRM ones. I bought one and have done a few thou miles without issues, and I know Greybeard has one too (I think he twigged me to the idea)

 
Quote
It may have been an old circlip re-used .................a round groove.

Or- your bores ......................., with a step on top, where they meet.

Any of those alignment issues, especially combined with detonation, and/or play in the big ends, can hammer the pin and circlip out.

  Geez- in my case I figured I must've just forgot to put 'em in.....
                      .......suddenly makes me look a bit better than I thought.*smile*.... *bash* (getting real)




Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
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Offline BSAnders52

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Re: A10 break down, analysis
« Reply #22 on: 28.05. 2017 11:05 »
Hmm, the thought has struck me, it may very well be my own mistake that has come back to haunt me.
I have no idea if there has been any repair or work done to the pistons since it left my care..

Ah, last time there was a piston job, when I owned it, it was professionally done, I did not do it..
It was after an other similar chain of events.
But since it worked very well, for long time..

I will have to ask the present owner, if they have any records on engine work and repairs..

Doesnt really matter, it is dammaged, it needs repair. No point in trying to find out whos fault it is.
It may as well be material faults, or wear, simply..

Ahh, I just found out it most likely is allreaddy on the last over size, +.60..? Only three over sizes? Then it is reslieveing? New cylinders?  Bugger.

Anders
Sweden


Offline muskrat

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Re: A10 break down, analysis
« Reply #23 on: 28.05. 2017 11:58 »
G'day Anders.
A sleeve for the bores are in order as I doubt another 20 thou (0.5mm) will clean that up. I have a pair of these sitting on my bench  http://www.feked.com/hepolite-bsa-a10-cylinder-liner.html
Then go back to standard size pistons http://www.feked.com/hepolite-piston-for-bsa-a10-gold-flash-650cc-models-etc-1950-62.html
Main bearings  http://www.feked.com/crankshaft-main-bearing-bsa-a7-and-bsa-a10-ariel-fh-67-0670.html
http://www.feked.com/crankshaft-main-bearing-bush-bsa.html
Shims for end float  http://www.feked.com/bsa-crankshaft-shim-set-a10-a7.html
While it's down check the cam & idler bushes. Replace the oil retaining ball and spring (also known as the anti wet sump valve. Check the crank pins for size and grind to the next size if required. Put new shells in.
 The sludge trap is inside the crank pins accessed by the big grub screw in the crank web. Look here at the two minute mark  https://www.youtube.com/watch?v=5VH1vwK5_k4  yours if a small journal won't have the radial bolt or a tube.
That'll keep you busy foe a while.
Cheers
'51 A7 plunger, '57 A7SS racer now a A10CR, '78 XT500, '83 CB1100F, 88 HD FXST, 2000 CBR929RR ex Honda Australia Superbike .
Australia
Muskys Plunger A7

Offline BSAnders52

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Re: A10 break down, analysis
« Reply #24 on: 28.05. 2017 13:46 »
 *eek*That film about the sludge trap was a horror movie!
I certainly expect something similar in this engine. If not else, this convinced me I am in for a complete overhaul. Down to the bone.. and back.
I vaguely remember the crank has been in for a total refurbishment at some point. But again, that is very long ago..

You are probably right about the sleeves.

I have found your site last night googeling, feked.com, but you are in AU. Reasonable prices, but the postage for theese heavy things will cost a fortune. Hmm, I am going to Sydney in winter, to see my daughter, maybe a bit too late.. I dont plan to be back very quickly.. as long as the visa will allow me.
I would like to have this fixed before I leave.. but with no hurry.

Oh gosch, why was I entangeled in this..
Life is a slow surprise..

Anders
Sweden



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Re: A10 break down, analysis
« Reply #25 on: 28.05. 2017 13:57 »
Amazing just how easily that sludge trap came out. If only they all did that.
2 twins, 2 singles, lots of sheep

Offline RichardL

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Re: A10 break down, analysis
« Reply #26 on: 28.05. 2017 14:59 »
Anders,

It seems the natural place for you to check out for parts would be basmotor.se. You probably won't get all you need from them, or any one source, but the postage for their parts should be tolerable.

Richard L.

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Re: A10 break down, analysis
« Reply #27 on: 28.05. 2017 15:24 »
Anders,
Feckd are in the UK.
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Online chaterlea25

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Re: A10 break down, analysis
« Reply #28 on: 28.05. 2017 15:33 »
Hi Anders,
A click when turning the engine slowly over can be heard, the valve springs force the follower to turn the cam to take up the backlash in the timing gears,
On engine faults that develop into a downward spiral  :(
Lack of oil changes and or high mileage leads to wear on the timing side bush
This results in low oil pressure, that does not open the PRV to supply oil to the cam trough
The first signs of problems are usually increased valve clearances due to worn cams and followers
Shrapnel from the cams and followers is thrown upwards and gets stuck between the pistons and bores leading to scoring and rapid wear
further shrapnel gets picked up from the sump and carried to the oil tank,
then back to the oil pump and into the ever decreasing cycle of destruction *problem*

Unless you dismantle the engine completely and clean everything especially the crank sludge trap and then scrupulously clean out the oil tank, you are wasting money fitting a new oil pump

John
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Offline BSAnders52

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Re: A10 break down, analysis
« Reply #29 on: 28.05. 2017 17:57 »
Anders,

It seems the natural place for you to check out for parts would be basmotor.se. You probably won't get all you need from them, or any one source, but the postage for their parts should be tolerable.

Richard L.
Anders,
Feckd are in the UK.

I know them well, ,Basmotor they live just near by from me. They are well reputed, so most likely I will try to use them as much as possible = no postage.. ;)They dont stock any new oil pump though, just re-worked used original pump, as an exchange service. You give them your old and get a new-ish instead. Maybe I can get them to order one for me.. a new one.

Aha, I got it wrong. It was very late in the hours when I found Feckd, when they are in UK they are within reasonable distance. I might even go to UK this fall.. Yet another reason to make it real.

Thanks for all good thoughts so far.
It will be a very serious rebuild, of the whole engine. Dont worry.
Btw, the present owner has put a magnetic bolt in the sump lid. It had done its magic, had a big wad of steel filings. So at least that debris did not "recycle" in the lubriction system.

I might even be inspired and eventually start to put my 1971 Royal Enfield Interceptor S2 together..I do miss to have a British twin to roar about with. But the RE is quite another animal than the docile BSA. And there are two decades between them.
Drems, dreams
I will have to deal with reality first.

Anders
Sweden