The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: Swarfcut on 22.08. 2020 09:20
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Reading posts of what folks find after a new purchase or a roadside failure makes me realise there must be a huge amount of stuff of interest being pictured and worth sharing.
Any thoughts on something along the lines of "just a picture"......... featuring the blow ups, failures and previous owner bodges?
Swarfy
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Limited to A7 & A10's?
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Guilty.
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GB A7 and 10 as an obvious watch and learn, let's see what other folks reckon.
Musky. Innocent until proven..... Exhibit A Yup... A class act.
Cheers.
Here's one I made earlier.
MI Motorway, Newport Pagnell 1971 Outside lane, running fine. Felt a little hesitation......
Swarfy.
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That picture of a claggy sludge trap should be mandatory viewing for people who want to put modern oil in one of these engines without a proper clean!
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Well said GB. Used heat around the plug hole as an aid to getting the plug out with minimal violence. All was revealed!!! Back in the day the sludge trap got just a brief two line mention in the service sheet. Folks reckoned they were sealed for life and left well alone, and the crank grinders kept quiet and knew you would soon be back again.
Amazing that up to then it had run just fine. So, don't chance it, clear it out.
Crank survived, rod, barrel were scrap. Piston skirt broken, valves bent. Cylinder head reused with new valves and guides. New oil pumps were still in production and second hand engines regarded as junk, bought one from Bob Joyner's on the Wolverhampton Road in Oldbury. Crank reground at Gordon Smith's in Halesowen, and a quick mix'n match put it back on the road.
Sadly these businesses are all gone.....
Swarfy.
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GB A7 and 10 as an obvious watch and learn, let's see what other folks reckon.
Musky. Innocent until proven..... Exhibit A Yup... A class act.
Cheers.
Here's one I made earlier.
MI Motorway, Newport Pagnell 1971 Outside lane, running fine. Felt a little hesitation......
Swarfy.
I have two spare pairs of crankcases, and one crank, that I will only part with when I cannot ride the A10 anymore 🙄
I also have a badly welded up timing side case that matches the drive side on the bike but will always be just an ornament *shh*
But I am banking on someone one day selling new barrels *pull hair out*
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Some evidence of a few minor incidents over the years. Norton crankcase sliced clean in half. The engine was still running on one.
Snapped A10 crank. The odd broken con rod or two. Or three . As for pistons...
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what was left of the timing side bush. i'm sure i'm not the only one
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Autojumble "spare" magneto.
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Swarfy,
Great topic! Not looking forward to sharing any future events, but not so optimistic as to think there will be none.
Richard L.
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Dismantled an SA gearbox I bought a while ago in good faith on a bike jumble.
Seems to have been run with grease in it. *problem* Found traces of grease all over the place...
These boxes have a reputation for being sturdy so I don’t dare imagine how this one has been treated.
All gears are absolutely knackered, one of the cam levers has been broken and (badly) welded, the gear change lever shaft is twisted... would need a pretty heavy person to stand on the lever for it to twist like that... *bash* *work* All that because some ham fisted knob taught that filling the box with grease was a good idea to get rid of the oil leaks... *doh*
Main shaft, lay shaft and cam seem to be reusable and the housing and covers aren’t too bad either.
At least I have a box of spare parts now...
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Excuse me for saying... great topic!
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Did I write up how I drove from Scotch Corner to London with one piston removed from the engine of my Ford Consul?
Seems I did:
https://www.a7a10.net/forum/index.php?topic=8199.0
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Did I write up how I drove from Scotch Corner to London with one piston removed from the engine of my Ford Consul?
Seems I did:
https://www.a7a10.net/forum/index.php?topic=8199.0
Yes, but a great story worth re reading
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In the sixties a firm I worked for had the contract (more of a lodge handshake I believe) to re-commission the machinery on a small island recently bought by a millionaire. There was a tractor, landrover and numerous pumps, generators, winches etc to sort out. One day I was there with the boss’s son and as we needed to use the tractor to move something in the generator room he went off to get it. Now there was a tarmac track leading down to the generator house (containing three large Listers). This track headed towards the edge of a 300ft steep cliff before turning right to the generator house. As it was a sunny day I was sitting on the grass admiring the scenery waiting for him. I heard the tractor (Ferguson 135) coming and then nothing. I looked around and saw Dennis standing on the bend with a cloud of dust rising behind him. I asked him what he’d thrown over the cliff, and he replied “ the t t t trrrrraactor”. Now this tractor had a forward loader attached but no counterweight on the back, so when he got to the bottom of the track he couldn’t slow down – the back wheels just locked.
We walked around into the bay below to investigate the situation. The tractor was broken in half, resting halfway down the cliff. With absolutely no means of salvaging it other than by helicopter, we went back up and Dennis went to the owner’s mansion to explain the situation. He was very good about it, saying he could easily replace the tractor, and gave Dennis a couple of large brandies to steady his nerves.
Now Ive spent many hours driving tractors (still have our 135) and jumping off the rear of a tractor as its going over a cliff must be darn close to impossible. Dennis was real lucky that day. The tractor remained there for years, but I presume with the new owners it is now gone.
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in a similar vein - When I drove a Fergie 35 we used to look forward to the smaller tractors job of leading grain from the combines to the drier (early 60s) the Combines were also MF, the driver sat to the left hand side of the combine, below the drivers seat was where the toolbox lived, un beknown to me a favourite trick was to site an oilcan in the toolbox with it's spout sticking out in line with any driver pulling alongside to empty the combines bin, the combine driver just had to move his foot back onto the top of the toolbox and pump it to deliver a scoot of oil onto the driver emptying the bin and yes that's exactly what happened.
I jumped off the 35 not quite managing to select neutral and it took off, being young supply and quite fast I ran after the trailer, climbed up the back of it intent to save the situation by getting back to the tractor seat via the trailer, the tractor meanwhile had found it's way to the edge of the field, crashed/jumped through a hedge headed across the corner of the adjacent field and was heading towards a dean (shallow wooded gully with a stream flowing through it).
I had by this time decided the situation was beyond saving and jumped out of the trailer.
Damage to the tractor was only a bent radius rod, damage to my status was a severe ticking off from the boos at the repair shop and leg pulling for quite some time, but a let off in as much as it's debatable what the outcome would have been if I'd stuck to my plan, and the estate manager got the whole story somehow (not by me) as I got a stern look and nothing else, combine driver possibly got a word or two I don't know
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Back in the early 70's (thats the the 1970's before anyone else *smile* ) a mate and I ran a little lockup garage just for spending money but we gained a good reputation and we made a bit of money. Any way one day a guy rolls up in a moggy minor ,it was chuffing like a steam train and the owner said it was down on power .We opened the bonnet and low and behold there was the reason ,a rod sticking out the side of the block, the other 3 working away as normal . Been a bit slow for the past MONTH said the guy shaking our heads there was a muttered "wonder why"before we started phoning round for a replacement motor.
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When our kids were young we were camping at Barn Farm Birchover Derbyshire near a stone quarry. We got to know some of the workers. One day we saw a young chap we had befriended, looking rather pale, walking back to the stone cutting sheds. He normally was seen driving a skip lorry full of waste up to the top of an empty quarry where he undid the back chains of the skip and tipped the contents out. When asked what had happened he said, in his broad Derbyshire accent; "Tippt lorry downt quarry!". He must have overdone things or the weight was too much because as he moved the skip out, the front of the lorry rose up and he jumped out before it went over the edge. We went and had a look. Way down below us there was a nearly new Renault skip lorry laying on its side among the rubble.
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You should have a time delay so that new owners can%u2019t access this strand until they have owned they bike for at least two years!
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Sorry this is a bit tame.
(https://i.postimg.cc/KvSR5R6t/866-E686-C-75-C2-4936-875-A-E60-BD6431-F1-D.jpg)
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Sorry this is a bit tame.
(https://i.postimg.cc/KvSR5R6t/866-E686-C-75-C2-4936-875-A-E60-BD6431-F1-D.jpg)
I'm glad you marked it so you can get it back in the way it was!
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I'm glad you marked it so you can get it back in the way it was!
Wouldn’t want to assemble it with the hole in the wrong place.
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Induction Bias??? Got to admit that's an all time classic just in time semi failure. Neat.
Swarfy.
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Induction Bias??? Got to admit that's an all time classic just in time semi failure. Neat.
Swarfy.
Twin carbs seemed to be fixing the previous induction bias, until...
(https://i.postimg.cc/CLbgkVfK/B7769-ECD-3-DAD-4514-8-E2-B-ED28-A4-B1-A63-A.jpg)
The crack in the piston reached the gudgeon pin hole.
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I simply refuse to add any pictures that will remind myself of just how bad an engineer I was when I was about 17
Its embarrassing and I refuse to participate *smile*
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When I was 16, (1966) I sold my Excelsior Consort, (98cc of raw power) and bought an Ariel Huntmaster with a sidecar chassis attached. One evening, heading toward home after blasting around west London, the bike started to misfire. I put my hands behind the silencers to feel which side was duff. I felt a sudden pain in one hand! When I looked, there were pieces of piston ring on my palm. I continued the journey home! An engine rebuild followed.
I didn't know about sludge traps then so that job did not get done.
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My dual 650 engine Triumph land speed race bike was being tested on rural public roads...The front engine left cylinder went lean and or detonated for unknown reasons. Forged piston seizure...
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not sure how many of you watch the MotoGP, but talking about major disasters and hair raising events, did you watch the Austrian GP of 2 weeks ago, when Rossi missed a flying bike by microseconds? and then the following week Maverick Vinales "stepped off" his Yamaha when travelling at 215 km/hr, because his brakes failed completely....here's the video....
Take a look…
https://www.facebook.com/MotoGP/videos/there-were-no-brakes-vi%C3%B1ales-on-frightening-crash/332353007915479/
the sound is muted on the video, you may need to unmute it too….
I cannot imagine the microsecond decision making process that passed through his head to decide that stepping off the bike at 215 km/hr was the best possible decision he could make!! (but it evidently was!!)
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Incredible video! You'd think he could have engine braked to slow the bike down a bit before he ejected.
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F/all engine braking on those. That's the job of the huge multi piston, carbon fiber brakes!! LOL
Cheers
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F/all engine braking on those. That's the job of the huge multi piston, carbon fiber brakes!! LOL
Cheers
Well, I didn't know that. *good3*
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Thought I'd revisit this thread as feeling a bit jaded and fancied a way to count my blessings in these strange times.
For those recent new members, here is somewhere to share those things that came as a surprise with that newly purchased pride and joy. The skip truck story still creases me up, it's the way he tells them.....plus enough good reasons to keep me well away from agricultural machinery.
Bodges, disasters, heroic failures, defeat from the jaws of victory, tall tales, W.H.Y.?
SW.
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No pictures on this ,only my memory, but back inn the 1967 s I purchased my second a10, a swinging arm a 54 ,with ariel type hubs and a non runner, good price or so I thought . Once persuaded to run it sounded like the proverbial bag of nuts and bolts ,or as one of our group with a great love of the english language said " it was like 2 skeletons having a bonk in a tin box " . I heard about an old spare plunger motor going for a few pounds and purchased it and then spent swopping the innards of one for the the other ,net result surprised us all . It waas the smoothest A10 I ever owned ,it was treated terribly as only youff can treat things but it was unburstable ,eventually it was left for a few months and cannabalised and reduced to parts whoever got the motor got a good en!
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My beloved SQ 4,
no futher comment: *eek*
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^^^ damn, any findings of what caused that ?
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Got to be a partial seizure at one or other end of the rod, probably small end.
What causes a seized small end? Tight clearance in a rebuilt engine; otherwise it could be detonation.
What causes detonation? On a low compression engine like that, I’d suspect a weak mixture. Inlet air leaks?
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A known Ariel SQ 4 sickness:
1. Sludge trap full, big end overheated/sizes/break on cylinder 3 or 4. Rod hit the case.
2. Lengthening through material fatigue of the aluminum con rod, the piston touch a valve, the piston disassembles, the cylinder liner breaks .....
but everything can be repaired ....
Engine is running again!
Rudolf
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I have heard that confession is good for the soul. It seems that a few of us have years of guilt to cast off. *roll*
My first bike was a 1957 BSA A7. I was a 17yo farm boy in 1968 and just finishing High School, no licence and I had to get my older brother to ride it home. It blew a cylinder base gasket on the way home. So before I had ridden it, I stripped the top end down. My only previous experience was dismantling a 1946 BSA C10 when I was 15, new rings and re-assemble.
Neither Dad nor brother had any mechanical skills, so I was on my own *dunno*. The small end bushes were knackered, so I replaced them myself using a bolt and washers etc. The gudgeon pins would not fit, so I had to open the small end bushes a little didn't I? Having no mechanical tools or experience, I found a round rat-tail file in Dad's farm shed. Now that did the trick thought I. I later told a workmate about the rat-tail file and he said "You did what???"
Not long after, a persistent rattle demanded another strip down. *red*
By this time my confidence had become enormous *wink2*, so I ventured into the bottom end. I felt lots of movement in the Timing Side, so bought a new T/S bush, heated up the case and dropped it in. What a great job thought I.! Gee I was a real motorcycle mechanic!!! I got new cam-ground high-compression pistons and had someone else replace the small end bushes.
Knowing nothing about line-reaming or end-float, I slapped the crank back in, assembled the motor and was ready to start it.
I could not kick the thing over. I just stood on the kick starter and nothing happened. So off with the chaincase, and I turned the crank over using a Stilsen (adjustable toothed spanner) for about a half hour. *red* I had the sense to realise that normal oil would be too thick, and the only thing else I had access to was the farm tractor's 44-gallon drum supply of diesel fuel. I filled the oil tank with diesel. After a further hour of Stilsening, it had freed up enough to go to the next level. No spark plugs of course ( I had worked some things out)
Our farmhouse was at the bottom of a slight hill of 200 metres long. I pushed it up to the top several times, and ran the bike down until the motor turned quite freely.
Then drained the diesel, re-filled with oil and kicked it over. It started quite well. I became aware of excessive frothing in the oil tank, so had to drain and refill the oil several times until the frothing stopped. There was a bit of noise in the top end, and a seizure followed caused by the larger diameter pistons hitting the head. I had not chamfered the head to allow for the higher crowns. I filed off the excess metal from the skirts, ground a chamfer on the head and slapped it back together.
Anyway the A7 ran beautifully and reliably for another year, before a 1959 Matchless 600 twin with purple metalflake tank and aluminium guards stole my heart. It was in the window of a bike shop in Newcastle (NSW). I swapped it for the A7. The Matchy went terribly until three weeks later I discovered that it was fitted with an air slide which was in the closed position. I eventually sold that to my mate Phil (photographed). The last I remembered of the A7 was seeing it on display in the bike shop window with a large sign - "New Engine with Cam Ground pistons". I couldn't hide quickly enough *red*.
I hope I have moved along a little since then. *lol*
Col
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I have heard that confession is good for the soul. It seems that a few of us have years of guilt to cast off. *roll*
All that goes to prove how tolerant these engines are.
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Hey Col, sounds like top notch engineering to me. Some of us are still at it!
*yeah* *bash* *beer* *good3*
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Not so much of a mechanical disaster, more a solution to a Plunger Motor that refuses to scavenge, after all else has been checked.
The disaster is that the motor has to come apart to access this pesky pick up pipe.
Posted on main forum but reproduced in this thread as a handy reference.
Pictured are a couple of Pick Up Pipes, the top miscreant has a poorly welded right angle joint. Crack allows air rather than oil to be drawn up.
Swarfy.