Oil Tank Bottom Mount Options?

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hudson29

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With the oil tank now out on my 1972 Commando because of a broken rear mount, its time to look at options for the bottom mount. One Forum member suggested that the bottom mount should not be used. OK, fair enough, but what replaces it? Now is the time to decide what to do as the work on the rear hub & brake is proceeding and I want to get this bike back on the road ASAP.

Vintage Paul
 
I have professed in the past the all three mounts need to work together. If one of the upper mount (usually the rear) breaks, then undue stress is related to the others. When things vibrate and move around, the lower can suffer because the most stress is relayed to that point.
Get the upper mounts sorted out and the lower will take care of itself.

But, if you are so inclined, send it out and we'll see you on the road in a week or two or three.
 
15 years ago the bottom tank mount of my 73 850 fractured.

I removed it then, and did not replace it, just ensured the top two mounts were in good shape and ignored the bottom.

No issues now after all these years and some 25,000 miles with no bottom mount.

The top two are rubber mounted and so insulate the tank, the bottom would hold it rigid there, so what?

Stupid of me? Quite possibly! Tell me why I should install one.
 
1up3down said:
15 years ago the bottom tank mount of my 73 850 fractured.

I removed it then, and did not replace it, just ensured the top two mounts were in good shape and ignored the bottom.

No issues now after all these years and some 25,000 miles with no bottom mount.

The top two are rubber mounted and so insulate the tank, the bottom would hold it rigid there, so what?

Stupid of me? Quite possibly! Tell me why I should install one.
Click to expand...
My point was that the guy wants to get back on the road and to fix what is broke and not what isn't.
Are you saying that he should hammer off the bottom mount for a long term fix? :P
 
The bottom of the oil tank is more prone to crack and break due to it being a solid mount as compared to the isoelasict mounts on the top. My tank was in good condition when I got the bike earlier this year but went ahead and sent it to CNW for the Oil tank modification where they clean it up, braze a plate on the bottom and send better iso mounts. CNW did a great job and I dont have to worry about the tank breaking and putting all the oil on the ground and siezing up the engine!!!
 
Hey Paul. You can do what Matt @ CNW does which is to grind the bottom mount down a bit & weld a plate across the bottom to strengthen it from cracking. Then glue rubber foam padding on the bottom so it sitts nice. It's really a good idea to strengthen the bottom from cracking while you have it out. Read the old posts on this by doing a search of them. You will see why you want to do this. The bikes been sitting for 12 years, don't get in a hurry now & regret it later. I will try to stop by today & show you how you can do it. Remember I have accsess to help from Wilson & he will help you for a " small donation" Glenn.
 
No, I am not saying he should hammer off the bottom for a long term fix.

I was not giving any advice of any kind.

I just wanted to point out that I personally feel that the bottom mount is a source of fracture, and in only my own experience, not only not "needed", but also not wanted.

That's all, not tying to tell anyone what to do or not do. Sorry if relating my own experience came off as advice.
 
1up3down said:
No, I am not saying he should hammer off the bottom for a long term fix.

I was not giving any advice of any kind.

I just wanted to point out that I personally feel that the bottom mount is a source of fracture, and in only my own experience, not only not "needed", but also not wanted.

That's all, not tying to tell anyone what to do or not do. Sorry if relating my own experience came off as advice.
Click to expand...
I was just kidding with you. but whether it was advised or not, it is probably worth noting and concidered a good tip and it is something I will more than likely do next winter. Thank you for the advise.....I mean tip.......I mean relating your experience. :D
 
pvisseriii said:
I guess i better get my hammer out.
Click to expand...

Still don't know what you are hammering.

What I did:

Used bigger rubbers from the headstead/exhaust. Had to hog out the mounting holes slightly.
Hung oil tank from top mounts.
Did not use bottom bolt.
Velcroed the oil tank to the battery box.

Velcro allows a slight mount of movement of the tank but will not cause it to fracture. Top of tank is suspended but no torque from the bottom mount.

If it breaks you can be sure I'll come on here and say what a bad idea it was. But I'm not concerned. :mrgreen:

Pictures here:
combat-proddy-build-t4186-120.html#p59866
 
Thanks guys, I am very grateful for any help deciding what to do with the limited abilities & resources available to me. I know many of you have had experience with the tank mounts and have come up with good workable solutions. My bike is down now but will soon be on the road again and I want to solve this problem and move on to other issues. Your guidance is appreciated!

Right now I still do not understand the solution proposed by those who suggest doing away with the stock lower mount. What replaces it?

Vintage Paul
 
Thanks for the clarification and the pictures. I see now what you did. What sort of load do the top mounts carry? Do they do any lifting or do they more or less just hold the tank in place while the velcro does the work?

My tank looked great when I installed it with new rubbers and I was surprised to find it loose less than 700 miles later . . .

Vintage Paul
 
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