Tank front mounting.

[Bevel bob]

On my Mach1/Mark3 tank I have a simple bolt /steel washer on the outside and a flat rubber washer between the ears and frame,not the easiest to fit, what was the orriginal fitment (a grommet?) and has anyone found a suitable substitute?.

[MotoMike]

I found gromets in the help section at the autoparts store that were designed to pass wires through a bulkhead. the one I found was a tight fit in the hole and protruded on boths sides so that when snugged the tank metal does not touch the frame.

I think one of the aftermarket guys make those special parts, a shouldered rubber piece with a steel sleeve.

I bet these guys could provide but don't know what their minimum is.

http://allstaterubber.thomasnet.com/vie ... |1018|1019

[JimF]

Bevel Rubber has "Widecase" tank grommets... Anyone care to comment if they will fit narrowcase?

http://bevelrubber.com.au/cart/index.ph ... ucts_id=29

[DewCatTea-Bob]

By: Bevel bob...
" what was the orriginal fitment (a grommet?) and has anyone found a suitable substitute?. "

____ Originally, the n-c tank-ears were press-bolted directly against the frame's threaded mounting-bosses, with just relatively short 8x1.0mm bolts through 18mm wide washers.
As a result of such minimal attachment means, the tank-ears were prone to cracking most anywhere outside of the washers' edge !
To help prevent that, I always added a pair of large fender-washers !
____ Here's a good method to fix the front mounts to work more like the superior method which the w-c tanks employ...
First drill-out the holes in the tank-ears at least large enough to accept basically the same 10mm-OD.split-bush/sleeves which are normally fitted within the shouldered rubbers employed in the w-c tank-ears, (that means enlarging the 8+mm holes out-to at least 11+mm, [probably not over 12mm, so that the sleeve fits tightly] ).
Then insert into the enlarged holes suitably-sized rubber-grommets -(much the same type as those rubber-rings which protect the fitting of cables in-through the headlamp-shell, except with a 9to10mm-ID. & a 11to12mm-OD. *).
Then insert the sleeve-bushings through the rubber-grommets (possibly requiring lubricant), and as the tank-bolts are tightened-in, their pressure is exerted upon the steel-sleeves through-to the frame (and not the tank-ears & rubbers), thus the bolts can then be fully tightened without smashing the rubber-grommets, which in-turn allows the tank-ears to be rather isolated from the (otherwise direct) vibration (which normally takes it's full toll on the tank-ears).
If the sleeve-bushings are long enough to leave too much side-to-side slop,, then add an extra washer, preferably fender-type.
(* I got a small-box of such rubber-grommets from an auto-parts store, and their measurements [roughly] are 1/4" thick with a 1/16" slot, 3/8" ID. x 1/2" OD. by 7/8" dia.width.)
__ Most all n-c Scrambler owners are especially quite aware of what normally happens to the original tank-ears, due to the stock mounting method (& extended vibration).
While I've never bothered to try the above n-c tank-mount modification on n-c tanks which were yet undamaged, I have used this mounting-idea -(inspired by the w-c mounting-method), on near 1 in 3 of the n-c Scrambler-tanks of which I've had to repair their cracked-up mounting-ears, and this modification always worked quite well, (just use a ream-bit rather than a drill-bit, on the stock tank-ears though) !


Dukaddy-Dukes,
DCT-Bob

[Teckhardt]

W/C tank bushings with the metal sleeve are also available from Guzzino

http://www.guzzino.com/gastabusewcs.html

[Bevel bob]

Its clear from DCT Bob's comment that the Narrowcase had no provision against vibration and that this was rectified in the widecase design, unfortunately the WC fittings are not suitable. The clearance between the ears and frame is only a millimeter or so and it appears that the way forward is to cut down the frame bosses to allow space for the rubber and a steel sleeve, however there's not much there to start with.

[DewCatTea-Bob]

" Its clear from DCT Bob's comment that the Narrowcase had no provision against vibration and that this was rectified in the widecase design,
unfortunately the WC fittings are not suitable. "

____ Right, that's all correct.


" The clearance between the ears and frame is only a millimeter or so and it appears that the way forward is to cut down the frame bosses to allow space for the rubber and a steel sleeve, however there's not much there to start with. "

____ I did not mention anything about my mounting-method requiring the frame's protruding mounting-tab/bosses to need to be reduced because, whenever a cracked tank-ear couldn't be repaired by simply welding-on a sizable washer, I'd instead neatly cut-off all of the cracked area of the ear (just tip most section), and then weld-on a new match-fashioned piece of steel-plate, (all looking fairly stock from the outer-side). _ And it was actually the added piece of plating which the rubber-grommet was fitted into, thus creating slightly added space for the protruding rubber to fit in-between.
However the rubber protrudes less than 2.5mm on the inside of the tank-ear, so your stock (un-repaired) tank-ears could fairly easily be spread-apart just enough to let the rubber clear the frame's mounting-bosses,, and I don't think that the tank-ears being spread 4mm further apart, would then look too warped-outward to be noticed.


Hopeful-Cheers,
-Bob

[Bevel bob]

Thanks all, as this bike is riden regularly and hard I will have to get this done.

[DewCatTea-Bob]

" I will have to get this done. "

____ Then be careful to employ a good/safe method for spreading-out your tank-ears...
I'd suggest clamping pieces of wood to both sides of the entire ear-mount, starting-out with whichever ear appears to be currently positioned most inward, and only bend outward a little at a time while closely checking to make sure you don't exceed the 2mm of desired outward repositioning of the ear. _ And then you'll likely find that the other ear need only go about 1.5mm outward.
__ Besides using pieces of flat wood on the whole ear itself, a wood-post (wrapped with a foam-sheet or something), could be used to help hold the tank still while the ears are being bent.


Hopeful-Cheers,
-Bob