Tank mounting crack

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I would concur that the 'mounting studs' are more of a locator than a fastener. If you want, I found zorries, or flip-flops make great spacers for the tank. Use as needed to space the studs above the wings in the tunnel and use donuts from the same material to space it also. It's a great consistency for the spacers. I got rid of those hateful nylocks and use another nut as a locknut, so it's not stressing the studs in the tank and it's easier to get off. You can see I've also made an AL plate to add underneath the wings, I had one break off from too much stress. F/G tank, but the same thing applies.

Tank mounting crack
 
Welding the tank when filled with water is par for the course in my neck of the woods nothing unusual at all. Diesel tanks welded when full of diesel as well.

J
 
DogT said:
I would concur that the 'mounting studs' are more of a locator than a fastener. If you want, I found zorries, or flip-flops make great spacers for the tank. Use as needed to space the studs above the wings in the tunnel and use donuts from the same material to space it also. It's a great consistency for the spacers. I got rid of those hateful nylocks and use another nut as a locknut, so it's not stressing the studs in the tank and it's easier to get off. You can see I've also made an AL plate to add underneath the wings, I had one break off from too much stress. F/G tank, but the same thing applies.

Tank mounting crack
Click to expand...

Your picture makes me speak out... I've been thinking it, but now I have to. Nobody has mentioned the stud contacting the side of the hole... direct metal to metal contact where there is supposed to be isolation . My '74 has two rubber washers with a shoulder (like these: http://www.mcmaster.com/#vibration-damp ... ts/=uq5ijq ) to locate and isolate. Were these factory Norton stuff? or added to my bike somewhere along the way? I see the parts diagram on www.oldbritts.com doesn't show them. The same result could be achieved by slicing some thin pieces of 3/8" fuel line and adding them in.
 
Rohan said:
DogT said:
. I got rid of those hateful nylocks
Click to expand...

Nylocs are hateful ??
The things you learn on these forums....
Click to expand...

I just found it interminable to get them off and the ratchet would beat up the front down tubes, plus getting maybe 3 clicks on the ratchet. A lock nut can be taken off with your fingers once it's loosened with a standard spanner. You have to realize I've got the 'S' pipes too. YPYMYTYC
 
Actually, I think mine came with donuts that had flanges on them that went into the holes, but I find I need to push my tank all the way back to keep the stanchions from hitting the tank. Early bike, very small turning radius. I'm not sure the studs hitting the wings is a big issue. I stand to be educated.
 
auldblue said:
Welding the tank when filled with water is par for the course in my neck of the woods nothing unusual at all. Diesel tanks welded when full of diesel as well.

J
Click to expand...

Yeah I know quite a few people who have gotten away with it too.
I was also about 25 yards away when a friend died welding a tractor tank full of water. That was enough to convince me. Jim
 
When I weld a fuel tank, a rinse with isopropyl alcohol (DryGas) mixes with and washes away the gasoline residue, then dump it out, stick the air hose in for 5 minutes and all vapours are gone. Safe and sound.
 
As a Boilermaker/ Welder I personally would not try to weld a sheet metal tank when it held liquid with any form of "electric" welding.
I have heard of people welding sheet metal tanks with 'oxy/acetylene welding torches that held liquid but......

Edit.
Somewhat off topic but remember this ?

https://www.google.com.au/search?q=weld ... 8QeF5YDAAw
 
DogT said:
Actually, I think mine came with donuts that had flanges on them that went into the holes, but I find I need to push my tank all the way back to keep the stanchions from hitting the tank. Early bike, very small turning radius. I'm not sure the studs hitting the wings is a big issue. I stand to be educated.
Click to expand...


Not calling your baby ugly, (it's a GREAT looking bike!) :mrgreen: just bringing to light a detail that all the posts previous in this thread hadn't mentioned, and, some of us are pretty hung up on detail... :twisted: for functionality, not just museum quality. Perhaps your glass tank is not as adversely affected by vibration, but the tin tank certainly doesn't want to touch metal to metal. Every modern bike, (and every vintage one I've been exposed to) even with the smoothest of engines, uses a system of rubber mounts to ensure no contact. There is a reason for it. :idea:
 
concours said:
DogT said:
Actually, I think mine came with donuts that had flanges on them that went into the holes, but I find I need to push my tank all the way back to keep the stanchions from hitting the tank. Early bike, very small turning radius. I'm not sure the studs hitting the wings is a big issue. I stand to be educated.
Click to expand...


Not calling your baby ugly, (it's a GREAT looking bike!) :mrgreen: just bringing to light a detail that all the posts previous in this thread hadn't mentioned, and, some of us are pretty hung up on detail... :twisted: for functionality, not just museum quality. Perhaps your glass tank is not as adversely affected by vibration, but the tin tank certainly doesn't want to touch metal to metal. Every modern bike, (and every vintage one I've been exposed to) even with the smoothest of engines, uses a system of rubber mounts to ensure no contact. There is a reason for it. :idea:
Click to expand...
Can't disagree with you at all. I just found that it wasn't a problem for me, but I don't even know if the studs hit the wings on mine. Somehow I doubt it or I'd hear it. I just found the tank mounting position a bit more important on my bike for some reason.
 
Not to get off topic......but,
My wife's grandfather who worked as a welder at the Naval ship yard told me something interesting. When he owned a garage he welded up a lot of automobile fuel tanks. His trick was to completely fill up the tank with gasoline and then weld it. He said as long as there was no vapors it would not explode. I do NOT recommend this at all, but did find it informative (?)
 
Deets55 said:
Not to get off topic......but,
My wife's grandfather who worked as a welder at the Naval ship yard told me something interesting. When he owned a garage he welded up a lot of automobile fuel tanks. His trick was to completely fill up the tank with gasoline and then weld it. He said as long as there was no vapors it would not explode. I do NOT recommend this at all, but did find it informative (?)
Click to expand...

Always believe an old person.
 
Every tank crack thread always warns that once brazed only braze can be used again but gosh if done right it should last forever being stronger than the surrounding metal and if it did crack again say from a crash then just braze and grind back again. The issue filling with gasoline is there is a leak right where the welding is being done, ugh. A Shade tree like me, near a decent size city might get some dry ice chips to drop in tank and leavel cap loose so CO2 displaces the
O2 and have at it.
 
needing said:
Deets55 said:
Not to get off topic......but,
My wife's grandfather who worked as a welder at the Naval ship yard told me something interesting. When he owned a garage he welded up a lot of automobile fuel tanks. His trick was to completely fill up the tank with gasoline and then weld it. He said as long as there was no vapors it would not explode. I do NOT recommend this at all, but did find it informative (?)
Click to expand...

Would you say that he liked you much, if at all? :D

He is correct but I still use water to completely fill and submerge most of the tank in a tub anyway.
Click to expand...

I very much doubt it was done with a electric welder. :roll:
 
Deets55 said:
Not to get off topic......but,
My wife's grandfather who worked as a welder at the Naval ship yard told me something interesting. When he owned a garage he welded up a lot of automobile fuel tanks. His trick was to completely fill up the tank with gasoline and then weld it. He said as long as there was no vapors it would not explode. I do NOT recommend this at all, but did find it informative (?)
Click to expand...

That would actually be safer than water as far as explosion. The mixture would be too rich to do anything except burn.

Water with a little air trapped above it can easily contain enough gas fumes to reach an explosive mixture. A cup full of air/fuel mixture around 13 - 1 makes a pretty big bang when it's ignited. When it is sealed up in a tank full of water something is going to give.
Kind of like my physics teachers demonstration of blowing a safe with a firecracker -as long as the safe is full of water.
 
comnoz said:
Deets55 said:
Not to get off topic......but,
My wife's grandfather who worked as a welder at the Naval ship yard told me something interesting. When he owned a garage he welded up a lot of automobile fuel tanks. His trick was to completely fill up the tank with gasoline and then weld it. He said as long as there was no vapors it would not explode. I do NOT recommend this at all, but did find it informative (?)
Click to expand...

That would actually be safer than water as far as explosion. The mixture would be too rich to do anything except burn.

Water with a little air trapped above it can easily contain enough gas fumes to reach an explosive mixture. A cup full of air/fuel mixture around 13 - 1 makes a pretty big bang when it's ignited. When it is sealed up in a tank full of water something is going to give.
Kind of like my physics teachers demonstration of blowing a safe with a firecracker -as long as the safe is full of water.
Click to expand...
wow i didnt know that! i have welded quite a few petrol tanks full of water ,i once had a flame pop out the filler cap hole but thats all, also when i pressure test a tank i never go above 4 psi i once accidently put 18 psi in a BSA tank and buckled the hell out of it.............baz
 
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