Author Topic: 51 Plunger Tank Strap and other questions.  (Read 3591 times)

Offline LJ.

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Re: 51 Plunger Tank Strap and other questions.
« Reply #15 on: 21.04. 2010 17:59 »
I also took some photos of the underside of the petrol tank... seems Richard has beaten me to this again! Richard you'll notice on mine that there are two rubber bungs, either side, in the holes where your support bar goes, they help to stabilise the tank, but would be no good for the smaller American market tank. I just still don't know why you guys have a smaller tank??
Ride Safely Lads! LJ.
**********************
1940 BSA M20 500cc Girder/Rigid- (SOLD)
1947 BSA M21 600cc Girder/Rigid-Green
1949 BSA A7   500cc Girder/Plunger Star Twin-(SOLD)
1953 BSA B33  500cc Teles/Plunger-Maroon
1961 BSA A10  650cc Golden Flash-Blue
1961 BSA A10  650cc Golden Flash-Red

Offline gold33

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Re: 51 Plunger Tank Strap and other questions.
« Reply #16 on: 22.04. 2010 01:15 »
Now I confused!
I don't have the isolating block coming down off my frame, is this a feature of later swing arms perhaps?
It is not in the diagrams in my parts manual either (neither is the strap)
I like the pipe with flattened ends, looks neat
Darren
'52 Plunger

Offline LJ.

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Re: 51 Plunger Tank Strap and other questions.
« Reply #17 on: 22.04. 2010 08:51 »
Oh no! Just realised that I could be responsible for your confusion... I've posted  pictures of a swinging arm tank and not a plunger. Think I need to go out and look at my Plunger Star Twin's frame, although a 1949 early frame might be different to later A10/7 frame. Sorry ignore my last post.
Ride Safely Lads! LJ.
**********************
1940 BSA M20 500cc Girder/Rigid- (SOLD)
1947 BSA M21 600cc Girder/Rigid-Green
1949 BSA A7   500cc Girder/Plunger Star Twin-(SOLD)
1953 BSA B33  500cc Teles/Plunger-Maroon
1961 BSA A10  650cc Golden Flash-Blue
1961 BSA A10  650cc Golden Flash-Red

Online muskrat

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Re: 51 Plunger Tank Strap and other questions.
« Reply #18 on: 22.04. 2010 12:50 »
Yes Darren, my '51 hasn't got the block or strap under the tank. The plunger tanks are mounted fore and aft so are not as prone to splitting.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Offline beezalex

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Re: 51 Plunger Tank Strap and other questions.
« Reply #19 on: 23.04. 2010 13:55 »
I believe the tank strap was introduced around '52-'53 for A10's only.
Alex

Too many BSA's


Offline MG

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Re: 51 Plunger Tank Strap and other questions.
« Reply #20 on: 23.05. 2010 17:56 »
Just wanted to add my solution.
I cut a trapezoidal strap from stainless, long enough to reach back to the bracket that is welded to the frame. You can also see the small piece of light-brown rubber inserted between the strap and the bracket.

This way, the strap not only holds the two tank halves together, but also holds the front part of the tank down to the frame, thus relieving the strain on the centre bolt. I thought that would be a good idea as the bracket/nut for the centre bolt needed welding on both my frames. Worked out pretty well so far.

Cheers, Markus
1955 A7 Shooting Star
1956 A10 Golden Flash
1961 Matchless G12 CSR

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Offline Big Nick

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Re: 51 Plunger Tank Strap and other questions.
« Reply #21 on: 23.05. 2010 20:44 »
fit a strap !
1932 500cc rudge
1936 500cc cotton pyton
1952 M20 with B31 motor
1952 Plunger A10
1954 New Hudson Autocycle
1962 A10
1982 BMW R100

Offline Sunbeam

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Re: 51 Plunger Tank Strap and other questions.
« Reply #22 on: 07.07. 2011 15:36 »
Anyone know why there are upper and lower antiroll rubber positions on the swinging arm frame.......(smaller tank?) I've bought 2 such straps in the past due to the original being missing and having problems fixing the front of the tank.
Each strap I bought was different, one was shaped (2 double sets in it) the other was flat. When I push the tank down on the top tube foams and anti roll rubbers,the bottom of anti roll bracket still looks as though it will interfere with either of the straps. I'm still unsure which position to fit the anti roll rubbers! Also, I can confirm that leaving this strap off will damage the tank.
Howard

Offline RichardL

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Re: 51 Plunger Tank Strap and other questions.
« Reply #23 on: 07.07. 2011 22:51 »
With but the pathetic experience of owning only one A10, and only having owned one A10, and being in a place/city/country where seeing another A10 at-large might happen every 10 years (if at all, as the only time I've seen another, while living outside Chicago since 1992, was at a vintage British vehicle show), I still have an opinion. And that is, I think the upper hole carries the bumpers when a 2-1/2 gallon tank is fitted, as is the case for my bike. From photos here on the forum, it appears the lower hole is used for the larger 4(+) -gallon tank. Ipso-facto, if I've interpreted it correctly, the bent straps should be for the 2-1/2 gallon and the straight ones for the larger tanks. In my case, as you've seen, no bent strap, instead, straight throught the lower hole.

On another point. I had to shave down the bumpers to get where the tank was a sane fit over them.

Richard L.
Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at https://www.gentlemansride.com for details.

Offline Sunbeam

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Re: 51 Plunger Tank Strap and other questions.
« Reply #24 on: 08.07. 2011 13:03 »
Thanks very much for the info Richard. I've a 4 Galllon tank fitted so it looks like bottom holes for the rubbers and use the flat strap.

Howard.
Howard

Offline RichardL

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Re: 51 Plunger Tank Strap and other questions.
« Reply #25 on: 08.07. 2011 13:54 »
So,  does it all line-up for that?
Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at https://www.gentlemansride.com for details.

Offline Sunbeam

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Re: 51 Plunger Tank Strap and other questions.
« Reply #26 on: 08.07. 2011 16:40 »
Hi Richard. Flat strap just about picks up if I push tank down hard. I'm sure bike's previous owner left it off due to central tank bolt cup being missing. All thread stud + thick rubber washers + nut  & washer have been used to pull tank down onto the frame top tube. Are the strap retaining nuts BSF or Cycle? Know the question was asked somewhere on the forum but I can't find it.

Howard.   
Howard

Offline RichardL

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Re: 51 Plunger Tank Strap and other questions.
« Reply #27 on: 08.07. 2011 17:18 »
Nuts!  ...............Parts book not handy, so thin on research material, but think they are probably BSC. Others can, please, chime in now.
Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at https://www.gentlemansride.com for details.

Online bsa-bill

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Re: 51 Plunger Tank Strap and other questions.
« Reply #28 on: 08.07. 2011 20:25 »
Pretty sure they're cycle. Haven't got around to fitting the strap on the RGF as yet
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 MG

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Re: 51 Plunger Tank Strap and other questions.
« Reply #29 on: 08.07. 2011 20:50 »
Yo, 5/16 Cycle
1955 A7 Shooting Star
1956 A10 Golden Flash
1961 Matchless G12 CSR

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