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Post by nortonjohn on Oct 11, 2023 18:57:10 GMT
I am helping a friend with his BSA Bantam. He says that his petcock keeps leaking and was wondering if there is a better one for his bike a D7 Bantam.
He tells me it is 1/8" BSP. I'm sure he can't be the only one with this issue.
Cheers
John
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Post by buttybach1932 on Oct 12, 2023 11:34:54 GMT
Hi John This is a problem area. The current fuel available in the UK has a percentage of ethanol added and it causes all sorts of problems with rubber and plastics. I normally advise people to use the E5 petrol which can have up to 5% ethanol. It has a higher octane rating which most old motorcycles do not need and it is more expensive. There are four different types of fuel tap available. The rubber diaphragm Japanese type are not normally available with a BSP thread to suit British motorcycles. The other three types are available with 1/8", 1/4" and 3/8" male BSP threads. SLIDE TYPE.Personally I do not like slide type fuel taps because they always appear to weep. The old original British taps had a cork sealing washer either side of the brass slide plate but the corks and slide plate suffered from wear and they wept fuel. New corks sometimes cured the problem but when the slide plate was worn it was a bin job. The modern replacement taps use rubber seals and they are OK when new but do not last very long with the ethanol in petrol. CORK PLUNGER TYPE.The cork plunger type last for quite a while providing that they do not dry out. I have them on my old motor mowers and providing that I fill the fuel tanks up for winter storage I do not have any problems. The corks do wear eventually but I make new ones from old whisky bottle corks which are normally made from nice close grained cork. Some taps are not designed to be dismantled but if they are old brass taps I modify them so the cork can easily be replaced. When I fit a new cork I lubricate it with silicone grease before fitting. TAPER TYPE.The taper type only leak if the seating gets scratched or scored. The big plus is they are not affected by the ethanol in the fuel or by being dried out. The problem with them is that they can get very stiff and difficult to operate. My father-in-law carries a short length of steel tube to use as a extension for the tap handle on his Tiger Cub. Last year I purchased a new taper tap for a friends BSA Bantam that has a PTFE liner so it is very smooth to operate. It was made by BB Engineering Supplies and the proprietor advised me that they are not affected by ethanol. He makes them for Autovac fuel systems but they can also be used as Motorcycle fuel taps. If my old taper fuel taps get stiff I dismantle them, give them a clean, reseat them with metal polish and re-lubricate them with silicone grease. That normally sorts them out for a few more years. I am not sure if any of the above helps you but hopefully it does Regards Butty Bach  |
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Post by lonewolf on Oct 12, 2023 12:42:11 GMT
Wotcha.
With my bike, I've tapped the hole in the tank to take either a metric thread or the larger 1/4 bsp thread.
I then use the taps advertised for the Indian Enfields - this also give me a reserve.
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Post by nortonjohn on Oct 12, 2023 20:16:18 GMT
Hi John This is a problem area. The current fuel available in the UK has a percentage of ethanol added and it causes all sorts of problems with rubber and plastics. I normally advise people to use the E5 petrol which can have up to 5% ethanol. It has a higher octane rating which most old motorcycles do not need and it is more expensive. There are four different types of fuel tap available. The rubber diaphragm Japanese type are not normally available with a BSP thread to suit British motorcycles. The other three types are available with 1/8", 1/4" and 3/8" male BSP threads. SLIDE TYPE.Personally I do not like slide type fuel taps because they always appear to weep. The old original British taps had a cork sealing washer either side of the brass slide plate but the corks and slide plate suffered from wear and they wept fuel. New corks sometimes cured the problem but when the slide plate was worn it was a bin job. The modern replacement taps use rubber seals and they are OK when new but do not last very long with the ethanol in petrol. CORK PLUNGER TYPE.The cork plunger type last for quite a while providing that they do not dry out. I have them on my old motor mowers and providing that I fill the fuel tanks up for winter storage I do not have any problems. The corks do wear eventually but I make new ones from old whisky bottle corks which are normally made from nice close grained cork. Some taps are not designed to be dismantled but if they are old brass taps I modify them so the cork can easily be replaced. When I fit a new cork I lubricate it with silicone grease before fitting. TAPER TYPE.The taper type only leak if the seating gets scratched or scored. The big plus is they are not affected by the ethanol in the fuel or by being dried out. The problem with them is that they can get very stiff and difficult to operate. My father-in-law carries a short length of steel tube to use as a extension for the tap handle on his Tiger Cub. Last year I purchased a new taper tap for a friends BSA Bantam that has a PTFE liner so it is very smooth to operate. It was made by BB Engineering Supplies and the proprietor advised me that they are not affected by ethanol. He makes them for Autovac fuel systems but they can also be used as Motorcycle fuel taps. If my old taper fuel taps get stiff I dismantle them, give them a clean, reseat them with metal polish and re-lubricate them with silicone grease. That normally sorts them out for a few more years. I am not sure if any of the above helps you but hopefully it does Regards Butty Bach View Attachment |
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Post by nortonjohn on Oct 12, 2023 20:19:28 GMT
In some places here in the US they still have non-ethanol gas available which is a big plus. I have forwarded on you replies to my friend, let you know what he says.
Again, thank you for your help.
John
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Post by buttybach1932 on Oct 16, 2023 14:29:09 GMT
Hi lonewolf
We were discussing the lack of reserve on a lot of British lightweight motorcycle at out last section meeting. We could understand it on very cheap lightweight machines but the 250cc 2T engined Cotton Double Gloucester does not have a reserve.
On BSA Bantams you just lay the bike on its side to get the fuel from the side of the tank that does not have a petrol tap. There is enough there for a few more miles. You now have two reserves, the two level fuel tap and the fuel left in the other side of the petrol tank. No bad thing as petrol stations are getting sparse in some areas of the country.
Regards
Butty Bach
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Post by lonewolf on Oct 16, 2023 19:51:50 GMT
On BSA Bantams you just lay the bike on its side to get the fuel from the side of the tank that does not have a petrol tap. There is enough there for a few more miles. You now have two reserves, the two level fuel tap and the fuel left in the other side of the petrol tank. No bad thing as petrol stations are getting sparse in some areas of the country. Regards Butty Bach Wotcha. I've done that in the past. My old M21 outfit only had one bolt holding the tank on, so I'd take that out, remove the tank and tip it to one side, then put it back on again. These days I'd rather have a reserve tap - I wouldn't like to put my Bantam down and pick it up again ( there's a chance it would be down there until someone gave me a hand ) One of the things I do with a reserve tap is find out how far it will take you. I carry a can of petrol with me, then when the bike goes onto reserve I check the mileage, then ride until it actually runs out of fuel. On the Bantam it take 23 miles before you fully run out |
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Post by 1951superlux on Oct 17, 2023 8:03:43 GMT
Hi lonewolf We were discussing the lack of reserve on a lot of British lightweight motorcycle at out last section meeting. We could understand it on very cheap lightweight machines but the 250cc 2T engined Cotton Double Gloucester does not have a reserve. A reserve is particularly useful on smaller 2-strokes because you want to use enough fuel to make room for more - you need to know there's enough space for the amount of oil you put in. If you've gone onto reserve you know how much you can top up by. |
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