Author Topic: Petrol Taps  (Read 4150 times)

Online bl**dydrivers

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Petrol Taps
« on: 06.12. 2008 17:47 »
Hello people

Is there anyone who can tell me the differences of the 2 types of petrol taps used on the A10?  Because in the A10 parts manual, there is 2 types of petrol taps, 1 being for the Super Rocket and the other for the standard A group.
Does it matter if I have the 42-8075 type on a Super Rocket, instead of the 65-8171 type? 

Ive come across NOS items, but is the type for the A group. 
Will it harm the performance or reliability?

Not sure if this information will help, but Ive added it also:
Got a Amal 389/47 Mono Carb

many thanks

Offline Beezageezauk

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Re: Petrol Taps
« Reply #1 on: 06.12. 2008 18:59 »
I didn't realise that there were two types of petrol tap until it was brought to my attention so the first thing I did was to check my parts list.  Yes, there are two types but the list shows one (42-8075) as a "Petrol Tap and Filter" for the A Group and the other (65-8171) as just a "Petrol Tap" for the A10S/R.

Now then, if you were to look more closely, after the 65-8171 there is a mark resembling a cross and at the bottom of the page it shows that the Petrol Tap with this cross is only fitted with the T.T. Carburetter.

This tells me that the 42-8075 is the one used with the 389 carb. 

Does anybody know how to distinguish one from the other apart from the 65-8171 not having a fuel filter attached?

Always willing to learn!!

Beezageezauk.   

Richard

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Re: Petrol Taps
« Reply #2 on: 06.12. 2008 19:20 »
On my gold flash tank i have two different ones fitted one with a cork and one with a chrome lever they both fit and both work
Does it matter?
Richard

Online Brian

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Re: Petrol Taps
« Reply #3 on: 06.12. 2008 21:15 »
I've been using this type of tap for a couple of years now and have found them very good. Not original but they are easy to turn on and don't leak. There available at most bike shops or online.

The gauze screws out and if its a main tap it will have a piece of tube sticking up, no tube if its a reserve tap. If you dont want the reserve ability just cut the tube off.

Online trevinoz

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Re: Petrol Taps
« Reply #4 on: 06.12. 2008 21:35 »
42-8075 type is the leaky plunger with cork seal one. The other one used, not sure of part number, is what is known as a "taper cock". Brass construction with a conical valve which seats in the body. Lever action like later types. Lever is round section. Also leaks.
Trev.

Offline RichardL

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Re: Petrol Taps
« Reply #5 on: 07.12. 2008 00:32 »
I sincerely doubt if my petcocks are original, but I like them. They are of the sliding cork valve type and, as yet, have not leaked. The pullout and turn-to-lock action just seems to me to say 'traditional" or "vintage" or something. One advantage of knowing one's A10 can never be considered concourse stock (or even close) is the freedom to do what makes one feel good.

One thing about my petcocks that was troubling was their right-angle design. It was rather tricky to get both of them to point straight backwards without over or under tightening. I ended up sanding fiber washers between two sanding blocks until I got them to the correct thickness for spigot alignment.

Regarding petcocks vs. carburetors, I am going to dare to step out of my direct expertise (again) and say that I don't see why one petcock would be better than another with respect to a specific carburetor. I can't imagine that any normal open petcock would have trouble keeping up with the engine in terms of keeping the float bowl supplied. Additionally, I would not think that a "normal" petcock would have an orifice so large as to overcome the effectiveness of the needle valve. Those who might might know that I am wrong, please tell me now before I embarrass myself further.

Finally, regarding reserve, I was of the impression that the tank tunnel in my 2g tank provides the division for reserve. Is this different in larger tanks?

Richard L.

Offline bezabill

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Re: Petrol Taps
« Reply #6 on: 07.12. 2008 12:11 »
oooooo ye it is

Online groily

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Re: Petrol Taps
« Reply #7 on: 07.12. 2008 17:51 »
Petrol taps? They come from B and Q (plumbers' merchants) don't they, at about 4 pounds apiece with proper 100% leak-proof guts, with standard gas threads on the outlets, to be attached to whatever adapter one has on hand or can make if they won't go straight on?
Seriously, as long as petrol passes (or not, as the case may be) and there's a filter somewhere . . . A purist can always make better-looking levers to avoid any accusations of having fitted something yukkie off the hot water system . . . I have a box of these things and they are better - as taps go - than anything else I have paid far more money for over the years. As in they don't leak. Whenever an original of-the-epoch tap fails, on goes one of these cheapies. Nary a problem. I have a good half-dozen in operation.
I shall never buy another authentic expensive tap, ever, be it push-pull or lever operated and am unconvinced by the 'snot right' argument. (The larger ones also make very good oil line cut-offs to prevent dribbles going where they aren't wanted and becoming a flood in the crankcase, and can be fettled to provide a magneto earth switch with a bit of ingenuity.) Most bikes sport a weird mix of taps, neither of which is often 'original' and neither of which, equally often, works properly.
Bill

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Re: Petrol Taps
« Reply #8 on: 07.12. 2008 22:03 »
Here is a taper cock as fitted to the sporty models. Pictured is my poor old RGS currently waiting restoration after many hard years. I have owned it for 37 years now.
Trev.

Offline RichardL

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Re: Petrol Taps
« Reply #9 on: 07.12. 2008 22:38 »
Trev,

I thought I had the record at 35 years. You have put me to shame and I will now go and hang my head.

Richard L.

Online trevinoz

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Re: Petrol Taps
« Reply #10 on: 07.12. 2008 23:00 »
I won't mention my '55 Flash which I bought in 1968.
Trev.

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Re: Petrol Taps
« Reply #11 on: 07.12. 2008 23:22 »
Or the Enfield Flying Flea which I bought in 1967. Probably never restore it. Trev.

Offline RichardL

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Re: Petrol Taps
« Reply #12 on: 07.12. 2008 23:42 »
Trev,

Is the '55 Golden Flash a swing-arm? If so, I would really like to see a picture to, perhaps, see what my '55 might have once looked like. Of course, I'd like to see a picture in any case.

Richard L.

Offline LJ.

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Re: Petrol Taps
« Reply #13 on: 08.12. 2008 09:55 »
Generally I've got on okay with the cork plunger type of taps, I think the secret of sucess with them is finding *Good* quality corks that have no veins/ridges and also that there is no grit in between the cork and side of tap which would soon act as an abrasive. I change mine with a full tank of petrol, yes messy but this flushes any dirt out. My spares are kept in a jar immersed in petrol ready for replacement so they are redily nice and soft. I dont think that boiling a dry cork for imediate use does them any good. A good smear of grease just before insertion and they have a good start off.
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