Author Topic: petrol tank mounting rubbers  (Read 299 times)

Online RDfella

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petrol tank mounting rubbers
« on: 09.06. 2019 11:30 »
Hello folks,
Making progress at last on the project (’62 A10 frame). Next issue to resolve is the petrol tank mounting. On my ’58 Flash there’s a rubber cup that sits over the nut in the frame which the central mounting bolt fits into. This prevents the tank rubbing against said frame lug/nut (there’s not much clearance for it inside the tank tube recess). I’m familiar with the rubbers which wrap around the top tube (42-8051) the ‘anti roll rubber’ (42-8052) and the rubber under the bolt head (42-8012). But there’s no mention in the parts book about a rubber fitting over that frame lug/nut. Is the one on my GF home-made perhaps? It doesn’t look like it. Certainly without such a rubber cup, the likelihood of the tank rubbing in this area is quite high. Does anyone have a source for such a piece of kit? Wrapping the lug in self-amalgamating tape would seem a rather agricultural solution.
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

Online RDfella

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Re: petrol tank mounting rubbers
« Reply #1 on: 12.06. 2019 16:13 »
No replies I see - does this mean the rubber cap fitted to my GF was home-made? Bit surprising if it was, given the amount of bodgery elsewhere. Why bother about something like that, when it's surrounded by mechanical mischief?
The tube in the tank is not that large and, in my view, there's a real chance the nut on the frame may rub inside the tube, especially the locktab under the inserted nut.  (29-8740 and 42-4078). As the locktab protrudes beyond the nut I therefore plan (on the bike I'm presently working on) to remove it and fit a piece of rubber hose or sumilar over the nut
.
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

Online Greybeard

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Re: petrol tank mounting rubbers
« Reply #2 on: 12.06. 2019 17:56 »
I cannot help I'm afraid. I hope you get a proper answer from someone who knows about swing-arm bikes.

Online bsa-bill

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Re: petrol tank mounting rubbers
« Reply #3 on: 12.06. 2019 18:32 »
Quote
No replies I see - does this mean the rubber cap fitted to my GF was home-made

I wonder if your confusing what appears to be a rubber cap with part number 42-8012 as can be seen in this link below to the Draganfly site
in the A/B group swinging arm  section for petrol tank fittings, it is actually a rubber spacer

https://www.draganfly.co.uk/bsa/bsa/a710--b3133--c101112--m202133/category/958-petrol-tank-mountings
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

Online RDfella

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Re: petrol tank mounting rubbers
« Reply #4 on: 12.06. 2019 20:18 »
No Bill, 42-8012 goes under the bolt on top of the tank. What I'm after is something under the tank. As stated, there's no mention of it in the parts book, so must be a home job. Now if only the PO had been as meticulous about the rest of the bike....
I suppose the best way to describe the rubber on my '58 GF would be like the rubber cap on the end of a walking stick - but with a hole in the centre for the bolt to pass through. Without something there, you're relying on luck that nothing rubs inside the tube.
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

Online muskrat

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Re: petrol tank mounting rubbers
« Reply #5 on: 12.06. 2019 21:09 »
G'day RD.
I made my own out of a car type shackle rubber to go under the Cafe's fiberglass tank.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7

Online RDfella

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Re: petrol tank mounting rubbers
« Reply #6 on: 12.06. 2019 21:24 »
Thanks everyone.
The one I’ve got is not only a snug fit on the nut (and the lug beneath) but it’s fluted on the outside, making it snug in the tank as well. Which made me think it must be an original or aftermarket part.
Not a problem in the great scheme of things. So self-amalgamating tape or rubber hose for frame no2 it is then …..
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

Online chaterlea25

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Re: petrol tank mounting rubbers
« Reply #7 on: 12.06. 2019 21:45 »
Hi RD
I have not ever seen a rubber "gdoing" that goes underneath the tank centre bolt mounting??
Rubber pads sit in front and behind the centre mount wrapped around the top frame tube
usually held in place with some insulating tape *roll*
Some folk use pipe insulation but I think it just keeps compressing until nothing is left  *sad2*

John
1961 Super Rocket
1963 RGS (ongoing)

Offline RogerSB

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Re: petrol tank mounting rubbers
« Reply #8 on: 12.06. 2019 22:41 »
On my 1960 GF swing arm there are only the two rubber pads on the frame, as John mentions, one in front of the tank mounting lug and one behind, in my case stuck with adhesive. Plus a rubber buffer on top of bolts that are each side of battery housing, also stuck down, as I'm always knocking one off and then have to fish for it when working with the seat removed.

1960 Golden Flash

Online bsa-bill

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Re: petrol tank mounting rubbers
« Reply #9 on: 13.06. 2019 10:12 »
Quote
I have not ever seen a rubber "gdoing" that goes underneath the tank centre bolt mounting??

No this is a new thing to me also, think you could be right RDfella it's a homemade remedy for I'm not sure what, don't think the tank should come that close to the frame nut
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

Online RDfella

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Re: petrol tank mounting rubbers
« Reply #10 on: 13.06. 2019 11:14 »
Certainly seems the rubber to which I refer is a home’un. I too have never seen one before, but then again I’m much more familiar with BSA singles than their twins. Point is that when I remove the tank, that rubber bush invariably comes off the nut and stays in the tank tube – meaning the frame nut & lug beneath must be entering the tube to some extent. Which in turn means we’re relying on the top bolt rubber to centralise the tank. Given the tank tube is not that large, to my mind that offers the possibility that the tank could rub on that nut (especially the locktab below it, as the latter is larger in diameter).
Dunno if anyone has ever experienced problems with a tank rubbing in this area (as stated in my original post, I’m aware of the top tube rubbers, the anti-roll rubbers and the bolt rubber) but never the less it does offer a secure location because I can feel the tank locating on that bush when lowering it onto the frame. Which is why I’d like to do the same on my project bike (which also has an A10 frame and tank).

Minor matter in the scheme of things though, just another ‘what do we do here’ on my long (but thankfully declining) list of issues to resolve. Have just finished sorting the throttle, choke, mag and decompressor cables and associated levers. When CWC deliver my front wheel rim I’ll build that and then it’s only a few bits n pieces before it’s ready to go on the rollers - which I’m currently rebuilding to get more wheel grip. If the bike’s a runner then it’s only left to sort mudguards, a seat, footrests and brake pedal, battery and wiring, an exhaust system, and ……….  Good job I’m not counting the hours on this bike build. Will upload an update photo when it’s on its wheels.
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

Offline Colsbeeza

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Re: petrol tank mounting rubbers
« Reply #11 on: 13.06. 2019 12:49 »
Hi RDFella,
I fitted a foam rubber pad wrapped partly around the frame front and back of the tank, and held on with cable ties (mainly because electrical tape softens and lets go with the hot summers down here).  The foam is thick enough to require a bit of pressure to get the tank down in position. They are about 6-7mm thick when compressed, and the tank centre definitely clears the tank bolt mount by a fair bit, maybe 6mm or so,?. There has never been a rubber under the tank mounting bolt fitting. So the tank should never get that close to the bolt mount.
Col
Colsbeeza
Australia

Online bsa-bill

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Re: petrol tank mounting rubbers
« Reply #12 on: 13.06. 2019 12:54 »
Quote
Dunno if anyone has ever experienced problems with a tank rubbing in this area

No I have never had the tank touch in this area, possibly this depends on having the correct (or enough) rubber around the top frame tube above and below the tank central mounting, my tank is a quite snug fit around the rubber on the top frame tube, sometimes takes a bit of adding or losing above or below to get the tank level
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