Custom Saddle Bag Mod - Question

[WSM]

Soon after my pops got his '96 Duc 916, he purchased a replacement rear cowl, fiberglass, resin and designed his own saddle bag mount for the Duc. He basically dropped two fiberglass slats down either side of the tail with fixtures to mount a pair of bags to them.

I'm looking to do the same to the Fiz.
Here is what I am thinkin:
Get a replacement solo cowl and mount two braces across it, wide enough to clear the rear fairing. Then mount two sheets of aluminum/fiberglass to those, with an extra support brace running underneath the tail section, just in front of the license plate, adding rigidity to the two sheets. You would then drill and attach the saddle bag mounting fixtures to the sheets, and the bags to those.
The best (ideal) part of it all would be that it would all be able to be removed by just unlocking the rear cowl and pulling it off, replacing it with the original cowl.

Here are two very quick mock-ups I did:

You could either run the top braces over the cowl, or run two shafts through two holes drilled into it.



What I am looking for from you inventive types, and you know who are, is any advice.
For the two sheets, I'm thinking 1/8" aluminum would be plenty light/strong.
As for the braces? Maybe extruded aluminum H or X would be plenty rigid, and easily mounted on top of the cowl, or just a half inch al tube going through the cowl.

Any help?

[yamaha_george]

hi,
If it were me i would go with the thro tubes as pemanent. I would put threaded rod through the tube to hold the bag panels.

OR

fab up a complete f'glass back side fairing along the lines of the original but deeper (very much like your second pic but coming forward under your legs making it look like a fuller race fairing but following the originals cut back but coming towards the ground more when not carrying bags and more streamlined when you are.
Loading points would be over a far greater area and not so prone to cracking since the passenger foot peg holders can now supprt the new fairing :-}

[WSM]

Thanks George,
Just as I hoped for, the modest and the grandiose!
I wish I had the money/shop to do the second, I do have the rest of the winter after all.

On the point you make about load bearing:
Would you consider the rear cowl a sufficient point on the bike for bearing weight? Now we're not talking fat-chick weight here, but say 40 pounds, tops. Obviously the seat can handle a passenger, but would the cowl and the way it is mounted be able to handle 30 lbs bumping up and down. Any concern of the plastic cowl cracking? Perhaps some heavy glue bracing the tubes to the cowl would help that.
And I was thinking of padding the underside of the two sheets with a foam which would be pressed against the rear fairing, dampening vibrations and limiting movement of the components.
That way it would be more of a cage around the rear fairing, braces on top and bottom, squeezing on the sides.

[the_finch]

I don't mean to be a downer, but there are easier ways of getting a set of saddlebags.

Here's a few pics of my '97 FZR600 with my expandable Technik Saddlebags I got off eBay for $40. They fit well and mount securely with the included straps, and there's even a strap that goes under the passenger seat, making it tougher to remove them without having the key to take off the back seat.

You may have a specific reason for wanting to do the mounts like that, but if you just wanted a good set of everyday saddlebags to use, a pair like mine would save you a lot of time and effort.

[WSM]

@the_finch,
Thanks for the tip. I'll look into those.
I blame my desire to tinker with things, rather than any actual necessity to build a custom system.

[yamaha_george]

Thanks George,
Just as I hoped for, the modest and the grandiose!
I wish I had the money/shop to do the second, I do have the rest of the winter after all.

On the point you make about load bearing:
Would you consider the rear cowl a sufficient point on the bike for bearing weight? Now we're not talking fat-chick weight here, but say 40 pounds, tops. Obviously the seat can handle a passenger, but would the cowl and the way it is mounted be able to handle 30 lbs bumping up and down. Any concern of the plastic cowl cracking? Perhaps some heavy glue bracing the tubes to the cowl would help that.
And I was thinking of padding the underside of the two sheets with a foam which would be pressed against the rear fairing, dampening vibrations and limiting movement of the components.
That way it would be more of a cage around the rear fairing, braces on top and bottom, squeezing on the sides.

WSM,
the hassle is vibration making the load far more than the static 40lbs weight you have in your hand.
Ideally the tubes would be welded to the sub frame and the holes in the fairing / cowling etc alittle bigger than the tube sothere is no contact from the threaded rod.

The passenger foot peg attachments to the new fairing / saddle bag rest could also be welded tube. that would effectively give you three robust mounting points.
As to foam or other padding waste of time as any one with atank bag will tell you the finest foam & dust will sand your paint down very quickly!

Rather than hang the bags down how about mounting the bag behind yoour butt, better aero dynamics yes it does make your C of G higher so carefully does it in the corners. do NOT put any high rise bar (like a seat back on a chopper behind you)
as any traffic cop will tell you they KILL by trapping you on the bike or snapping your spine in the event of even a slow speed fall.

I would troll the i/net to see pics of sportbike bag carriers and incorporate the best ideas I find.

A kind of rear side crash bar with holes in the bottom for bungee cords with avery low hoop just behind your but and the passenger hand rail as the other traverse, would give you fixings on 4 sides .