Author Topic: Rebore Vs Liners and removal of half time pinion  (Read 602 times)

Offline owain

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In June I'm planning to ride my BSA A10 (plunger) from Sweden to Wales. I'm just doing a quick mechanical restoration on the engine so that I can rely on it to get me there. The current cylinder size is 71mm with +0.040" pistons fitted. There is noticable wear ring (vändkant in swedish) at the top of the cylinders, so i've got the option to either bore the cylinder to fit +0.060" pistons or fit a new cylinder liner and fit std size pistons...The latter option being the more expensive. My logic is that a new cylinder liner and standard piston would be less likely to crack than an oversized +0.060" cylinder which would have a thinner cylinder wall...Any thoughts?

Also, I've taken apart my A10 engine but just have two pinions that I'm having a hard time to remove. According to the parts diagram there is a pinion key that keeps the pinion in place...How are you supposed to remove the pinions? I'm having quite bit of difficulty with a hammer
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Sweden & North Wales
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'69 BSA A75R

Online muskrat

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Re: Rebore Vs Liners and removal of half time pinion
« Reply #1 on: 11.03. 2017 11:42 »
G'day owain,  *welcome*.
You won't have any problems with +60 so long as you keep the compression down to say 7.5:1. The most important things are the sludge trap, big ends and main bush. If those are good you'll be able to do that trip another 20-30 times before liners are needed. At 60mph it should take 24 hours.
Cheers
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'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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Re: Rebore Vs Liners and removal of half time pinion
« Reply #2 on: 11.03. 2017 11:52 »
Oh, yes the crank pinion is a tight fit. You will see two slots on it's outer face, use a puller to extract it. http://www.a7a10.net/forum/index.php?topic=5352.msg36545#msg36545
Cheers
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'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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Offline owain

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Re: Rebore Vs Liners and removal of half time pinion
« Reply #3 on: 11.03. 2017 19:12 »
Nice one, cheers for the advice Muskrat. +.060" pistons and a special pulley it is!
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Offline duTch

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Re: Rebore Vs Liners and removal of half time pinion
« Reply #4 on: 11.03. 2017 19:40 »

 
Quote
I'm having quite bit of difficulty with a hammer

    *eek* *eek* *eek*


  put the hammer down- and with your hands in the air, gently push it away from you with your foot
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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
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Re: Rebore Vs Liners and removal of half time pinion
« Reply #5 on: 11.03. 2017 19:41 »
That'll cost you an intro over in Pictures, Stories & Introductions. How you came to be an A7/10 luver and maybe a picture or two.
Cheers
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'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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Offline Clive54bsa

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Re: Rebore Vs Liners and removal of half time pinion
« Reply #6 on: 12.03. 2017 06:04 »
I've had liners installed in both my '54 Golden Flash and my '61 Super rocket, standard pistons are quite easy to find, 15'000 on my SR and 11,000 on my GF no problems so far. I also had a liner fitted to my B50 (which was a liner originally from factory)
I'd go the liner route.
Clive
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Offline hdawson

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Re: Rebore Vs Liners and removal of half time pinion
« Reply #7 on: 12.03. 2017 06:56 »
Just having  a rebore with new 0.040 pistons after a major malfunction so good to know I have plenty of material left in my barrels.
Wishing you well Owain
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Re: Rebore Vs Liners and removal of half time pinion
« Reply #8 on: 12.03. 2017 07:55 »
I've got +080" 8.5:1.
if you google the threads some folk say you can push it to +100".
i plan to delay liners as long as possible, they're like hip replacements, false teeth and various unmentionable medical devices that as soon as installed will be one step closer to their own failure
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Online chaterlea25

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Re: Rebore Vs Liners and removal of half time pinion
« Reply #9 on: 12.03. 2017 23:05 »
Hi All'
Owain, Keep the hammer away from your BSA reserve it for the Triumph  *work* *angry*

Attached are pics of the legs I made to attach to a Sykes 2 legged puller
The legs look bulky but there is enough room for them  *smile*
They have been used many times , no problem *smile*

John
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