Author Topic: Pros and Cons  (Read 286 times)

Online Greybeard

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Pros and Cons
« on: 21.06. 2018 09:57 »
The Plunger and rigid(?) models do seem to have some good qualities that later machines lack.

Having never ridden one, I presume that the 'A' swinging arm rear suspension was an improvement, rather than a 'modernisation' to match other makers bikes; just having damped springing has to be an improvement.

The early six spring clutch is a beauty so why did BSA dumb it down? Cost saving?

The early semi-unit construction is great; compact, chains easily adjustable, but requires the engine out when you have to work on the gearbox. Was the later design made so a standard gearbox casing could be used on different models? Maybe BSA workshops asked for a more accessible gearbox.

The engine steady bracing on the early bikes is superior as it's not attached to the rocker box.

What are the pros and cons of early to later A's?

Offline Topdad

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Re: Pros and Cons
« Reply #1 on: 21.06. 2018 10:30 »
Hi Gb , I've had the pleasure of owing both plunger and s/arm although the plunger was attached to a chair . I loved the plunger  engine so smooth and yes the engine steady really works cos I tried it without ,bad mistake for all of 5 mins ! Yes the clutch I found great and I agree why did BSA get rid, Tank didn't split although I had to use rubber at the mounting points on the plunger  ,2 have on my 4 s/arm models  but over yrs and some harsh treatment .Getting the lump out of a plunger isn't a problem for a 17 yr old not so easy for someone of our age whereas I've changed g/boxes on the s/wing arm relatively easily within the last 2yrs .  As for the ride ,well my present bike is marvelous I can't comment on a plunger , as I said never ridden one solo. All in all it must be down to individual taste and what our pocket could afford at the time we got the bike ,Bob ( now for the comments from more knowledgeable folk )
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Online Black Sheep

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Re: Pros and Cons
« Reply #2 on: 21.06. 2018 11:46 »
Having both the plunger is a far better bit of engineering. The swinging arm one has a bit more ground clearance and a side stand and arguably slightly better handling. If it came to the crunch, the plunger one would stay.
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Online Greybeard

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Re: Pros and Cons
« Reply #3 on: 21.06. 2018 13:28 »
Having both the plunger is a far better bit of engineering. The swinging arm one has a bit more ground clearance and a side stand and arguably slightly better handling. If it came to the crunch, the plunger one would stay.
My Plungie has a side stand! The frame already had the mounting for one.

Online Rex

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Re: Pros and Cons
« Reply #4 on: 21.06. 2018 15:26 »
I wish mine did!

Online Greybeard

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Re: Pros and Cons
« Reply #5 on: 21.06. 2018 15:57 »
I wish mine did!
Does your frame have the mounting lug?

Online Rex

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Re: Pros and Cons
« Reply #6 on: 21.06. 2018 16:38 »
I wish mine did!
Does your frame have the mounting lug?

Sadly not. Another plus of the plungers is the duplex primary chain.

Online Black Sheep

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Re: Pros and Cons
« Reply #7 on: 21.06. 2018 20:48 »
The primary drive on the plungers is streets ahead. Duplex chain, slipper tensioner. The 8" half width front brake is the best BSA ever made. Why ever did they change it? The 6 spring clutch is wonderfully light too. None of this convinces my wife to abandon her '59 A10.
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Online edboy

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Re: Pros and Cons
« Reply #8 on: 21.06. 2018 22:09 »
personally i cant stand the silentbloc s/arm bushes and replace with needle roller bearings and grease. lots of work.

Online muskrat

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Re: Pros and Cons
« Reply #9 on: 22.06. 2018 09:00 »
My s/a handles and is suspended better but I love my plunger and do heaps more miles on it. I think the only downside of the plunger is the need to remove the whole lump to do a g/box rebuild. Only had to do that once in 35 years, 34 years ago!
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Online morris

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Re: Pros and Cons
« Reply #10 on: 22.06. 2018 11:59 »
I love to ride them both.
Depends on how I feel.
If I want to go for a more leisurely ride I take the plunger.
The SA feels more modern and "sporty" so thats my choice when I want a fast ride
But when it comes to build quality, the plunger definitly takes the points.
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