Fuel tank mount question

I have 2 Interstate tanks (steel) with one of them out of action due to cracking around the front bosses (where the studs screw in). I believe the Interstate tanks are known for this problem, being more than twice the weight (full) of a Roadster tank.

I'm aware that some folk use the rubber rear exhaust mounts in place of the OEM rubber washers with stud on the front tank fixings. Each will absorb vibration in a different way:
A) The stock system will be good for vertical vibes but not do much fore/aft & side/side.
B) The exhaust mounts will absorb almost no vertical vibes (very small amount of rubber between the 2 small embedded studs) but will be quite good at absorbing fore/aft & side/side vibes & forces.

Which one will be best?
The only knowledge I have is one data point - the bosses can crack with the stock system.
Has anyone tried the exhaust mount style and willing to give meaningful input?
Cheers

I have used the exhaust mounts from the Mini for all tanks for last decade or so with no issues, the gap between the 2 studs is not small on these and the rubber is waisted.

kommando said:

I have used the exhaust mounts from the Mini for all tanks for last decade or so with no issues, the gap between the 2 studs is not small on these and the rubber is waisted.

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Can you give a link of what you use?
Thanks

I use these with added rubber washers to get right height.




They have the correct UNF thread and are stocked by some Norton parts stockists. They are not the same thickness as the Norton silencer rubber buffers used on the rear.

Pretty sure Repco sell these rubber mounts

kommando said:

I have used the exhaust mounts from the Mini for all tanks for last decade or so with no issues, the gap between the 2 studs is not small on these and the rubber is waisted.

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I should check with you - do you use these on an Interstate tank?

robs ss said:

A) The stock system will be good for vertical vibes but not do much fore/aft & side/side.
B) The exhaust mounts will absorb almost no vertical vibes (very small amount of rubber between the 2 small embedded studs) but will be quite good at absorbing fore/aft & side/side vibes & forces.

Click to expand...

The foam pads (including the one on the tank strap which should always be fitted and tightened) need to be in good condition as they become hardened and compressed with age because the pads also support the tank and reduce the rocking that causes the cracking around the front mountings.

robs ss said:

I should check with you - do you use these on an Interstate tank?

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Used them on Interstate and Interpol, as LAB states you need to adjust the pads between the frame top and the tank bottom and not just reply on these buffers. I find you need to fit new pads, wait 6 months for them to bed in and then add a second set which will make the tank a bit high. Once the second set bed in then its about right.

You also need to check the stud length that you pick to screw into the tank to make sure it does not bottom out in the tank insert and break it.

kommando said:

I use these with added rubber washers to get right height.

REAR COTTON REEL EXHAUST MOUNT

The very rear bobbin type mounting rubber on every mini made until the introduction of a rubber hanger strap in 1992. When the [link]RC40[/link] or similar systems are fitted, 2 will be required. See [link]C-19G3258[/link] for larger upgrade.

www.minispares.com

They have the correct UNF thread and are stocked by some Norton parts stockists. They are not the same thickness as the Norton silencer rubber buffers used on the rear.

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Ha! I used the Commando exhaust iso mounts to hang my Mini's muffler. Seem to hold up well there. Guess Mini's system is not moving about as much as the peashooters.

Robs ss, thanks for raising this issue. I had my interstate tank off yesterday to lube cables and noted that I had never attached the rear bracket to the frame. It uses rubbers like the exhaust pipes with a metal bridge under the main frame tube. For years I've just relied on the seat to hold the back of the tank down because the rear mounts are tedious to screw down. On the tank I have there are no pips to hold a rubber band like on a roadster tank. I will go hunt up the under-frame bracket and install it forthwith. I will also re-check the front mounting rubbers as they are long-in-the-tooth by now, as am I.

Thomasa said:

On the tank I have there are no pips to hold a rubber band like on a roadster tank.

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The glass fibre Roadster tanks had pommels for the rubber band.
The steel Roadster tanks used the Roadster strap (different to the Interstate strap).

L.A.B. said:

The glass fibre Roadster tanks had pommels for the rubber band.
The steel Roadster tanks used the Roadster strap (different to the Interstate strap).

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Genuine Factory Spare Parts for Norton motorcycles built before 2002.

andover-norton.co.uk

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My Hirider tank uses a flat strap, while my Roadster tank has the curved on shown above. Both are steel tanks.