Author Topic: Newbie to a10 engine rebuilds  (Read 340 times)

Online Daveh67

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Newbie to a10 engine rebuilds
« on: 12.08. 2019 09:29 »
As the title says I've never done an a10 engine. So my question is what traps are there and what needs to be seen to.
So far I've got sludge trap, rod clearances and side play. What else to look out for. Lifters issues cam issues balancing etc etc.

At this stage it looks like 40 thou os bore is needed and I've not got the rods off yet but I'm not xpecting with the wear seen so far the crank may need a re grind too.

Just list the items and I can search through the forum to see

Dave.
1960 A10 the new toy
1930 AJS R6 outfit
1934 Triumph 2/1
1932 AJS TB6
BSA model K project

Offline bikerbob

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Re: Newbie to a10 engine rebuilds
« Reply #1 on: 12.08. 2019 10:03 »
If you are doing a complete engine overhaul then everything needs to be checked for wear and replaced if needed. One thing that is important and often gets overlooked is when you have the crankcases split in the half that holds the timing side bush you will see a small screw next to the bush, that needs to be removed and the small spring and ball behind it should be renewed this can only be done whilst the crankcases are split this important spring and ball helps against wet sumping. But make sure you get the correct spring and ball as the last time I ordered them I was given the wrong spring. Also make sure all the oilways are clear in the crankcase.

Online Daveh67

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Re: Newbie to a10 engine rebuilds
« Reply #2 on: 12.08. 2019 10:11 »
thanksbikerbob thats exactly what i need to know
cheers n beers
dave
1960 A10 the new toy
1930 AJS R6 outfit
1934 Triumph 2/1
1932 AJS TB6
BSA model K project

Offline Swarfcut

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Re: Newbie to a10 engine rebuilds
« Reply #3 on: 12.08. 2019 10:13 »
Hi Dave. From your list of bikes, I assume  its the new toy 1960 model you have apart. This will have most of the problems of earlier models addressed, but  the main reason for wear and failure is still the knife edge capacity of the lubrication system. Its a dry sump system, so failure or obstruction in oil feed is generally terminal, return failure is messy. As a consequence of poor lubrication, timing side crank bushes wear, and next in line comes big end failure and cam and follower wear. So make the lubrication system your priority, clean out the tank, the oil lines, check the oil pump, clean out the crank sludge trap before you consider spending anything on renovation, renewal or machining. Frequent oil changes with the correct type of oil for an air cooled motor is the secret. Most engines have suffered neglect in this aspect of maintenance. Lots of detail on the Forum....just go search.

 The conrods are the same forging, and if original should be marked 67 1160 but the one on the drive side (clutch side) should have a small bleed hole from the big end top shell which points towards the centre flywheel. The rods are fitted with the locating tabs for the shells at the front of the engine. It will have what is known as a big journal crank.....you lucky fella. bikerbob is spot on with that pesky li'l old valve. It is often overlooked, but is simple to check when the motor is in a thousand pieces.......

Good Luck.

Swarfy.

Online duTch

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Re: Newbie to a10 engine rebuilds
« Reply #4 on: 12.08. 2019 10:46 »

 
Quote
.. One thing that is important and often gets overlooked is when you have the crankcases split in the half that holds the timing side bush you will see a small screw next to the bush, that needs to be removed and the small spring and ball behind it should be renewed this can only be done whilst the crankcases are split this important spring and ball helps against wet sumping .....
Quote
.......bikerbob is spot on with that pesky li'l old valve. It is often overlooked, but is simple to check when the motor is in a thousand pieces.......

 Having said that,  if it's used often is not such a problem; it's more of a problem if only used occasionally.... *fight*; just needs diligent monitoring
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
Australia

Online Greybeard

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Re: Newbie to a10 engine rebuilds
« Reply #5 on: 13.08. 2019 16:44 »
The original Mazak oil pumps do not have good longevity. SRM sell a lovely aluminium billet pump but it's expensive. You may be able to find a steel pump; I think Wassell were doing them a tad cheaper than SRM. Me and duTch managed to buy alleged 'High Capacity' steel pumps from a 'characterful' chap known as Bantam John. That was about 6 years ago so who knows if he is still doing them!

If you decide to strip the original pump, take great care to record the exact locations of each gear, otherwise the thing is likely to be impossible to spin over when reassembled.

Offline Peter Gee

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Re: Newbie to a10 engine rebuilds
« Reply #6 on: 29.08. 2019 23:54 »
Check the  cam follower faces for wear, grooves and  dents caused by cam lifting  wear. They are NOT flat ground, despite what it may seem, but have a large radius.....I think 1.25" or more  and  the radius is very gradual and seems "flat".  Don't quote me and ask on this forum for the correct radius but far bettwe a reasonable original 4 of them than rubbish "new" parts, if you can. They have a large pad of Stellite on them that unless really worn thin, will take a re-radius.

I am not trying to boast but I have just rebuilt an A7SS engine in the middle of Africa with zero spares locally  or comparison engines. I did it by extreme reading and querying on this excellent site, Britbike Forum and others...there is no substitute for thinking hard about every single piece of your bike, let alone the engine.

The  gear oil system on a Beeza  makes you realise why Triumph stuck with plungers. I had to get a pump from USA..and it was ok and not butchered but needed extremely careful rubdown of both the "mazak" body, steel end plate  and a couple of the gear faces to make it all turn free without the lest hint of play. I would say I put 6 hours plus just into this..and then you have to get the mating surface  to the crankcase flat...using a piece of FLOAT glass minimum 1/4" thick  and say, 800 emery paper. This work is well worth the fine and patient trouble. And yes, that wretched ball  valve in the timing crankcase inner needs renewal. I kept the original spring as like elsewhere said, the replacement was too Chinese. But fitted a new ball and tapped it gently a few times with a suitable drift to re-set the seat.

For the timing side Crankshaft bush I  could not source the steel backed original, so I had my  machinist turn a copy, sized to fit the crank  timing side re-grind, from the correct grade pf phosphor bronze. It was then line reamed. Kibblewhite in USA do a ready to fit of high quality.

Replacement conrod nuts were an extreme pain..the ones being sold from most vendors being Chinese  'below par' wether Taiwanese or Beijingese. Eventually I went with the  originals plus Loctite....if you don't intend to race and rev like a madman, it should do fine.

Everyone has their faves on this blog.... I do not claim perfection or infallibility. Patience, sheck, double-check, consult. Hope it helps

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Re: Newbie to a10 engine rebuilds
« Reply #7 on: 30.08. 2019 08:49 »
Peter,
Interesting post.

Offline Sluggo

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Re: Newbie to a10 engine rebuilds
« Reply #8 on: 31.08. 2019 07:12 »
Really, Not enough info to properly answer.  Are you a Sunday rider and only on sunny days a few miles per year?  is it a show bike or a rider?  Do you muddle about barely getting above 45 or do you intend to wring it out and put it away wet, Screaming thru the gears with silk scarf flying the canyons of Mulholland drive at 2 am, trusting the feeble, flickering beam of the Prince of darkness?  Out along the coast highway, Salt spray in the face, the Still night air sliced thru with the bellowing megaphones,  cracking the ton.  The edge, only those who have crossed over know where its at.

If a Sunday rider or a office ornament polished by a secretary,, Then clean, inspect, measure and go with stock bits,  But if high mileage, dubious history and an intent to ride it hard, Then I think the following is mandatory.

A) Full inspection, dimensional testing (Is the cases true and everything square?) and Blue printing.
B) Aftermarket H beam rods (The originals are fine for Low RPM but they have a fatigue life, 60 years is asking a lot)
C) Upgraded oil pump.
D) Dynamic balancing. Static balancing is okay and better than nothing, But cant address rocking couple.  Its amazing the transformation after a good dynamic balance.

Also look carefully at pistons and valves. Repop and replacements tend to very variable in dimensions, tolerances and weights.  Many BSA pistons repopped today are totally different weights than originals.

Then you to are ready to ride like HST.

" So it was always at night, like a werewolf, that I would take the thing out for an honest run down the coast. I would start in Golden Gate Park, thinking only to run a few long curves to clear my head… but in a matter of minutes I’d be out at the beach with the sound of the engine in my ears, the surf booming up on the sea wall and a fine empty road stretching all the way down to Santa Cruz… not even a gas station in the whole seventy miles; the only public light along the way is an all-night diner down around Rockaway Beach.
There was no helmet on those nights, no speed limit, and no cooling it down on the curves. The momentary freedom of the park was like the one unlucky drink that shoves a wavering alcoholic off the wagon. I would come out of the park near the soccer field and pause for a moment at the stop sign, wondering if I knew anyone parked out there on the midnight humping strip.

Then into first gear, forgetting the cars and letting the beast wind out… thirty-five, forty-five… then into second and wailing through the light at Lincoln Way, not worried about green or red signals, but only some other werewolf loony who might be pulling out, too slowly, to start his own run. Not many of these… and with three lanes on a wide curve, a bike coming hard has plenty of room to get around almost anything… then into third, the boomer gear, pushing seventy-five and the beginning of a windscream in the ears, a pressure on the eyeballs like diving into water off a high board.

Bent forward, far back on the seat, and a rigid grip on the handlebars as the bike starts jumping and wavering in the wind. Taillights far up ahead coming closer, faster, and suddenly—zaaapppp—going past and leaning down for a curve near the zoo, where the road swings out to sea.

The dunes are flatter here, and on windy days sand blows across the highway, piling up in thick drifts as deadly as any oil-slick… instant loss of control, a crashing, cartwheeling slide and maybe one of those two-inch notices in the paper the next day: “An unidentified motorcyclist was killed last night when he failed to negotiate a turn on Highway 1.”

Indeed… but no sand this time, so the lever goes up into fourth, and now there’s no sound except wind. Screw it all the way over, reach through the handlebars to raise the headlight beam, the needle leans down on a hundred, and wind-burned eyeballs strain to see down the centerline, trying to provide a margin for the reflexes.

But with the throttle screwed on there is only the barest margin, and no room at all for mistakes. It has to be done right… and that’s when the strange music starts, when you stretch your luck so far that fear becomes exhilaration and vibrates along your arms. You can barely see at a hundred; the tears blow back so fast that they vaporize before they get to your ears. The only sounds are wind and a dull roar floating back from the mufflers. You watch the white line and try to lean with it… howling through a turn to the right, then to the left and down the long hill to Pacifica… letting off now, watching for cops, but only until the next dark stretch and another few seconds on the edge… The Edge… There is no honest way to explain it because the only people who really know where it is are the ones who have gone over. The others—the living—are those who pushed their control as far as they felt they could handle it, and then pulled back, or slowed down, or did whatever they had to when it came time to choose between Now and Later.

But the edge is still Out there. Or maybe it’s In. The association of motorcycles with LSD is no accident of publicity. They are both a means to an end, to the place of definitions
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Online BigJim

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Re: Newbie to a10 engine rebuilds
« Reply #9 on: 31.08. 2019 08:52 »
Can i be both depending what mood i'm in. Wish i had a secretary!
 *bright idea* *beer* *countdown*
Jamie,  Supporter of Distinguished Gentleman's Ride

Online Rex

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Re: Newbie to a10 engine rebuilds
« Reply #10 on: 31.08. 2019 09:24 »
I'll stick with the muddling then. Too old/sensible for screaming anywhere, but if I did want to do that I'd just buy a Kawasaki.
Makes you wonder how these bikes ever lasted until the end of the street when they were rebuilt on a Saturday afternoon in your dad's garden shed.

Online Greybeard

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Re: Newbie to a10 engine rebuilds
« Reply #11 on: 31.08. 2019 09:58 »
I'll stick with the muddling then. Too old/sensible for screaming anywhere, but if I did want to do that I'd just buy a Kawasaki.
My sentiments exactly. Treat these old girls with respect. Ride a modern for burn-ups.

Offline Sluggo

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Re: Newbie to a10 engine rebuilds
« Reply #12 on: 31.08. 2019 10:28 »
I'll stick with the muddling then. Too old/sensible for screaming anywhere, but if I did want to do that I'd just buy a Kawasaki.
My sentiments exactly. Treat these old girls with respect. Ride a modern for burn-ups.

Probably sensible, But anyone mucking about with 60 year old farm machinery on 2 wheels has questionable logic and common sense anyway, Let alone pushing them hard.

Ask my friend Tyler, Racing a 1950s Preunit and setting new records each year, Just like Icarus flying too close to the sun,,
He went down on the salt at over 100 mph, but will live to race again.   Common sense? Respect? Its all relative my friends.   *eek*

" He was a lucky guy. He said he got a bit of a front wheel wobble going while in fourth gear ands tried to move over and find a firmer bit of salt on the course. There wasn't firmer salt, all the race vehicles spinning their wheels over the course of the day had loosened the surface over huge areas. The wobble turned into a tank slapper and he went down. His front wheel taco-ed as he high sided and the bike went over 3-4 times taking him with it for at least one rotation. The bike was pretty beat up, but we took it back to the pits and the guys jumped on it and managed to start it up. The frame looks okay and it is definitely repairable. Tyler fared about the same, still running and repairable.  The x-rays show a unique series of fractures in his forearm's radial bone. A series of fractures running lengthwise from the joint. That is where the brunt of the impact from the crash went. As they say any accident you can walk away from...

See: https://www.lowbrowcustoms.com/blog/bonneville-speed-week-2019#sthash.A2zv2Xhn.dpbs
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Offline berger

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Re: Newbie to a10 engine rebuilds
« Reply #13 on: 31.08. 2019 12:56 »
haha SLUGGO " reach through the handlebars to raise the headlamp beam , forgot how many times I've done that.  enjoyed the read!