Tank mounting, not for the faint hearted!

alan · Post by **alan** » Tue Jul 25, 2006 12:54 am

hi,
what i did was, i bought two of the old type door stops, the rubber ones and cut and drilled to fit, cost me all of £1.20 the pair, by the way the bolts are drilled to wire them up.
regards, alan

good-hifi · Post by **good-hifi** » Tue Jul 25, 2006 10:22 am

All fitted now, the main problem I had was having was lining everything up. Eventually I found that the 'restorer' had shoved a great lump of U shaped rubber in the tunnel under the tank. Must have had an elephant holding the tank down to line it up.

To cut a long story short, I removed the LUMP of rubber, mounted the tank properly and now it sits proud of the frame and is supported by the tank rubbers.

Of course you cannot tighten these up too much otherwise the rubber supports will not do what they are supposed to do, hence the locking wire between the two front bolts.

All I have to do now is electrical rewiring on account of the fact the some of the wires were so badly routed that the seat chaffed through the main power lead from the battery and caused a minor wiring fire.

Which is why I had to remove the tank in the first place....

Cheers

deshollier · Post by **deshollier** » Tue Jul 25, 2006 8:11 pm

On the M20/G9 there are metal sleeves on the bolts to allow the bolts to be fully tightened and preventing the rubbers from being squashed too much. I imagine it would be the same for other models. The bolts should still be wire locked.

Biscuit · Post by **Biscuit** » Tue Jul 25, 2006 11:27 pm

Why should they be lock-wired?

good-hifi · Post by **good-hifi** » Wed Jul 26, 2006 12:06 am

quote: allow the bolts to be fully tightened

If the bolts are fully tightened one assumes that the tank is now rigidly fixed to the frame. So I'm at a loss to understand what the rubbers would now be doing.

Cheers

good-hifi · Post by **good-hifi** » Wed Jul 26, 2006 12:09 am

quote:
Why should they be lock-wired?

Because, unless the rubbers are squashed to bits, the bolts will not be fully tightened and if they are not lock wired they may vibrate loose and eventually drop out....

Cheers

paul knapp · Post by **paul knapp** » Wed Jul 26, 2006 3:32 am

Wrong!!!.........if you have the correct lengths of the rubber spacers, and correct length of spacer sleeve on correct length bolt, it will all "sandwich up" to give a firm, but flexable mount, which will help reduce vibration stress cracks in tank mount area....And look correct to the "roving eye."
Looking at tank mounts is a good indication of how carefully or skillfully a machine has been assembled....and I have seen some "shockers"....(a drop of loctite will not go astray)
Pablo .

good-hifi · Post by **good-hifi** » Wed Jul 26, 2006 9:14 am

One might assume that firm and fully tightened are not quite the same thing but maybe that is all a question of interpretation.

Of course all this is a moot point unless one is aware of the size and positioning of the rubbers and the length of the sleeve which brings us nicely back to my original question....[

Anyone who gets on their hands and knees examining my tank mounts deserve to see whatever it is they see...

Cheers

Biscuit · Post by **Biscuit** » Wed Jul 26, 2006 10:48 am

Thank you Paul. The spacers are there to fully tighten the bolt leaving the correct amount of 'squash' on the rubbers. The people who lock wire these bolts make me laugh, I bet they don't lockwire some of the most important fixings on the bike, ie. the two nuts and bolt on the front brake stay, if not why not?

Steve Martin · Post by **Steve Martin** » Wed Jul 26, 2006 11:15 am

Hello Mick.... there seems to be a bit of confusion here between the various types of mounting arrangements.
I assume your machine doesn't have the long 'bungs' that fit inside a socket and expand when the bolt is tightened. [If it does, I suggest common sense trial and error tightening.] That leaves at least two more arrangements:

Early: has a thick rubber [+ washer top and bottom] between the tank and frame mounting and a thin one [+ washer on top] under it, held in place by one drilled hex bolt [+ washer] and three 'tag washer' headed bolts; tightened up 'appropriately' and prevented from unscrewing by wiring up. I doubt if you have this arrangement.

Later: [not sure when], the same arrangement of rubbers, but fitted on a sleeve passing through the hole in the bracket. [One washer only, under bolt head] Thus, the bolt can be tightened up on the sleeve, and will remain as tight as any other fastening on the machine. Buying in the correct parts should ensure an appropriate fit, but it is simple to check:

The bolt,[plus washer] and sleeve should be of lengths that allow the bolt to enter the tank threads fully without bottoming on the tank, while tightening 'firmly', [whatever], on the sleeve. If the sleeve is about the same length as the two rubbers together, then the extra thickness of bracket between them will give about 1/8" of rubber compression, sufficient to restrain the tank while damping out some of the vibration. You don't need to wire the bolts up for normal road use.

It sounds as if the general problem is sorted, but if there is still any doubt, could you describe in detail the arrangement you have?

Cheers, Steve.