Author Topic: Great Mechanical Disasters  (Read 1386 times)

Online muskrat

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Re: Great Mechanical Disasters
« Reply #30 on: 07.09. 2020 10:20 »
F/all engine braking on those. That's the job of the huge multi piston, carbon fiber brakes!! LOL
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Online Greybeard

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Re: Great Mechanical Disasters
« Reply #31 on: 07.09. 2020 10:46 »
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*

Offline Swarfcut

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Re: Great Mechanical Disasters
« Reply #32 on: 26.02. 2021 10:25 »
 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.

Online Topdad

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Re: Great Mechanical Disasters
« Reply #33 on: 02.03. 2021 16:34 »
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!
" rules are made for the guidance of wise men and the blind obediance of fools"
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Offline Rookie_V#60

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Re: Great Mechanical Disasters
« Reply #34 on: 02.03. 2021 17:16 »
My beloved SQ 4,
no futher comment:  *eek*
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!

Offline a10gf

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Re: Great Mechanical Disasters
« Reply #35 on: 02.03. 2021 17:43 »
 ^^^ damn, any findings of what caused that ?

A10 GF '53 My A10 website
"Success only gets you a ticket to a much more difficult task"

Online Triton Thrasher

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Re: Great Mechanical Disasters
« Reply #36 on: 02.03. 2021 20:13 »
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?

Offline Rookie_V#60

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Re: Great Mechanical Disasters
« Reply #37 on: 02.03. 2021 20:33 »
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
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!

Offline Colsbeeza

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Re: Great Mechanical Disasters
« Reply #38 on: 03.03. 2021 01:49 »
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
Colsbeeza
Australia

Online Greybeard

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Re: Great Mechanical Disasters
« Reply #39 on: 03.03. 2021 08:40 »
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.

Online BigJim

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Re: Great Mechanical Disasters
« Reply #40 on: 03.03. 2021 18:26 »
Hey Col, sounds like top notch engineering to me. Some of us are still at it!
 *yeah* *bash* *beer* *good3*
Jamie,  Supporter of Distinguished Gentleman's Ride