Author Topic: Barrel not fitting  (Read 1835 times)

Offline Nourish

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Barrel not fitting
« on: 31.01. 2014 22:43 »
I've just received some thick flange barrels off e Bay but they won't sit in my BA7 crankcases - it looks like the spigot is fouling on the piece of crankcase between the mouth and the cam follower opening - is this usual - should I relieve the barrel spigot or the crankcase?

Online RichardL

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Re: Barrel not fitting
« Reply #1 on: 31.01. 2014 22:58 »
A picture is worth a 1000 words, as they say.
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Offline Briz

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Re: Barrel not fitting
« Reply #2 on: 31.01. 2014 23:01 »
Never had this problem putting thick-flange barrels on plunger cases, but If I did, I'd definitely be relieving the crankcase not the barrels.

Online orabanda

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Re: Barrel not fitting
« Reply #3 on: 01.02. 2014 01:56 »
Not A65?

Offline Nourish

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Re: Barrel not fitting
« Reply #4 on: 01.02. 2014 09:05 »
A10 Barrels?

Offline Stephen Foster

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Re: Barrel not fitting
« Reply #5 on: 01.02. 2014 09:58 »
They look like  A10 barrels to Me ?
I have never seen A65 ones however so cannot comment with certainty .
Perhaps You could photograph the flange view for confirmation ?

Steve ...
I own a 1955/56 B.S.A Swinging Arm "Golden Flash" , had it since 1976 .

Online bsa-bill

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Re: Barrel not fitting
« Reply #6 on: 01.02. 2014 10:22 »
Quote
You could photograph the flange view for confirmation ?

and the op of the crankcase

I'd say A10 defo as well
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline bikerbob

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Re: Barrel not fitting
« Reply #7 on: 01.02. 2014 14:15 »
I have an A65 and they are definately not A65.

Offline muskrat

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Re: Barrel not fitting
« Reply #8 on: 01.02. 2014 18:57 »
No two sets of cases are 100% the same. It's just the way castings were machined back in the day.
Adjust the cases not the barrels.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Offline Nourish

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Re: Barrel not fitting
« Reply #9 on: 01.02. 2014 19:14 »
That's two of you who say to relieve the cases and not the barrel - as it's under the flange and not where they usually break - Why?
Hope you can see where I've marked where they are contacting
Cheers

Offline muskrat

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Re: Barrel not fitting
« Reply #10 on: 01.02. 2014 19:22 »
The skirts of the barrels are thin enough. I've seen them brake off without too much provocation.
The cases won't be weakened by a little grinding there. I had to do similar to a set of CA7 cases.
Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Australia
Muskys Plunger A7

Online RichardL

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Re: Barrel not fitting
« Reply #11 on: 01.02. 2014 20:40 »
Well, I think this photo of my crankcase may answer the question. As you can see (and as I had never noticed before) the crossmember is relieved in the same place Nourish's/your's will be. It seems to me that the reason relieving the member ( *whistle*) was not previously necessary is that this is the first time the larger bore A10 barrels are being used on the A7 cases.

I have a frustrating, but now over, side note to this. In looking at crankcase diagrams, I noticed the alignment dowel in the crossmember. Before putting the cases together, I had forgotten to confirm the dowel in place. This meant disassembly, to be certain. Luckily, it had not been so long that the joint sealer had set, so the job was not horrible, but an hour of my life not coming back. The dowel was there.
'
Richard L.
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Offline Briz

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Re: Barrel not fitting
« Reply #12 on: 01.02. 2014 20:57 »
You could probably do without that dowel. The cases align via the register around the circumference of the mating surfaces. This ensures the alignment of the main bearings.
As long as the barrel flange is then properly flat they would be OK.

Online WozzA

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Re: Barrel not fitting
« Reply #13 on: 01.02. 2014 21:56 »
A little hard to see in this pic.... 
but my A10 cases have been releived of some metal at some stage like Richards,
I always wondered why.... now I know..   *smile*
 
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Online RichardL

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Re: Barrel not fitting
« Reply #14 on: 02.02. 2014 00:04 »
The look of the relief in Wozza's/your crankcase is very similar to the work in mine, which makes me think this was factory done.

Briz, I'm sure you're right about not needing the dowel for case alignment, but I was done by the time you wrote. Anyway, I was concerned that the dowel was also intended to provide an added element of stability for the slim crossmember. The fact that it's part of the breather path is probably not an issue.

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.