Need an idea on mounting a Givi plate to stock luggage rack

I'm brainstorming on how to mount this Givi monokey rack to my stock sportster luggage rack. The pictures pretty much show where everything needs to be, and you can see where the bolt holes are. I am a welder by trade and have a somewhat decent shop here. MIG and Stick, no tig capabilities. Have any needed hand and power tools.

I have an unlimited (kinda) supply of 1"x 1/8" angle iron and 1/8" steel plate here, and can go to Lowe's for anything else I might need.

Anyways, here's the pictures of what I'm working with:

Bottom of Givi mount, top of sportster rack:



From the bottom, where it needs to mount:




As mounted how it should sit:







Maybe build a frame to connect the two using some light square tubing, then bolt everything together? 1" by 1/8", make it square. Have 2 kickers coming off to catch the outside bolts, and both center crossmembers going across the sportster rack at the front and rear. Anyone see a flaw here, or have a better idea? I'd hate to spend all this time building this thing and have it not work right.


Maybe make it like this, only use straight lines?

You could also just use flat plate stock, and order the Givi mounting bits. Check this thread for the secret Givi Code.

http://www.advrider.com/forums/showthread.php?t=79750

Most hardware stores carry 1" x 1/4" 6061 alloy aluminum bars in 4' lengths. Get one of those and cut a front and rear crossbar to fit between the two brackets and bolt the stuff together- it's quick, easy, light, cheap, and only raises the Givi bracket 1/4" above the lowest possible mounting.

If you don't like the result it is easy to change. There are plenty of more complicated and perhaps better ways to do this but simplicity is worth a lot.

flat bar across the 2 forward points... 4 holes, 2 bolts in each bracket. or weld 2 ears on to the Harley rack.


then 2 angle iron bolted to the Givi & welded to the HD rack

How about getting a different monokey mount?

This one should have mount locations that fit your rack. Drill holes, mount, RIDE.

That's a monolock, my case won't work with it.



You guys really think flat plate would be enough? It seems like there would be a lot of leverage and start bending the plate. That's why I was thinking square tubing. I've only worked on cars and trucks though, I've never really fabbed anything up for bike use.

With the proper thickness, bars are enough- plate is overkill. What is the strength in the rest of the system anyway ? Determine the "weakest link" in your construction and decide if you want the adapter to be the weakest link or not. If you use bolts instead of welds you have a lot more flexibility to change things later.

Try this one



Givi E250

I think some bar stock should be enough, the original rack is supporting the weight, the bar stock is just positioning and securing the GIVI plate.
I would use SS bar.

The more I design this thing the worse it gets. Bolts are just in the worng place for the rack, it's not turning out like I want. I'm going to build the whole thing from scratch, it'll be better in the end anyways. Going to be a few months probably, I need to get the whole bike into the shop. The front of the shop is either mud, snow, or ice all winter. It's hard enough getting the KLR in, much less a Sportster.

I would suggest that you get one of the racks which Sanjoh has already suggested. I've used a couple on my Land Rover.

They attach using the square washers which you can see just to the left of the wavy brackets in Sanjoh's picture. Those square washers will fit into any of the recesses in the rack itself (they look to be diamond shaped in the pic, but are in fact square), so you have considerable flexibility in bolt placement.

All you would need to do is drill four appropriate holes in your existing standard rack and bolt the new Givi rack on top.

Or, cut it to fit mostly under the plastic mount, paint it black and be done.

Jim

You're on the right track, don't give up.

I went through a similar process mounting my Monolock to a Krauser rack. I used 1/4" aircraft aluminum plate to do it. I laid the Givi rack on the aluminum, and traced it with a pencil. Then I cut the plate to that shape. (damn that stuff is hard!) I filed the aluminum until it was exactly the same shape as the Givi rack. I used v-head stainless allen bolts sunk into the aluminum to keep the top nice and flat. Then I drilled the aluminum plate to bolt the Givi rack on top. The whole thing is very solid now. The adaptor plate I made is a bit heavy considering it is aluminum, but lighter than steel. I probably could have used 3/16" plate and been just fine. All you can see is a 1/4" spacer (painted black) between the Givi and Krauser racks. Perfect!

I don't have web based photo hosting, so I hope my description will be enough to go on. If not, PM me an email address. Good luck!

+1 on sanjoh's suggestion. Those Givi plates are pretty cheap and can be moved from bike to bike as needed also. Just attach it to the rack with all 4 screws and spread the attachment points out as widely as your rack allows. I am a mechanical engineer and have never done any stress analysis of topcase mountings .... I just look at it this way: the Givi cases attach with 2 small-cross section plastic tabs plus one latch, all fastening to a plastic case. Almost any rack mounting points that are aluminum or steel (for example the 1x1/4" aluminum someone mentioned) is far stiffer and stronger than the plastic even if it's cantilevered out an inch or two from the rack.

-dman

I think the problem is the metal rack only lines up with the Givi rack enough to give 2 mounting points, with the plastic about 50% cantilevered. An adaptor plate can be made to cover the whole base of the plastic.

I posted my pics to another site that can host them. Here is my home made adaptor plate:

If additional adapter plates are needed, consider using "mending plates". They are available in several widths and thicknesses & sold at HD in the same section as gate locks/door hardware.

I used two of these to mount an E250 to a generic KTM Adv plate, and it has held up fine for 15K+ miles.

That's the exact issue. I'm going to do what you did. Looks heavy but strong, should never have an issue.

1/4" plate? I should have some here, if not ill go get some.

All typos and misspellings blamed on my phone.

Why dont you just locate new holes in the plastic plate where they need to be, and counter sink them with flat head screws? I did this to mine and its rock solid.
No extra hardware, and you can position the box where you want it- back or up, then just drill the correct size hole into your rack and nut it from the underside.
Dont be afraid to drill into the Givi plate. It's a very stable, plastic injected product that's hard to crack. Just dull the edge of your drill bit a little, and it will not grab breaking thru the other side. I used 1/4 inch flat, socket head stainless steel screws from Home Cheapo with lock nuts on my GS and it's been on for a year and half with about 5k miles with no movement at all. Good luck

From the bottom, where it needs to mount:




As mounted how it should sit:

This is how u can have it - clamp it into position, drill right thru both the rack and the Givi plate. Just make sure u clear the web gussets in the Givi plate, then counter sink from the top side. You're done.

The alu bar stock/2 piece solution already mentioned is the quickest/easiest and will be stronger than the weight capacity of Givi case in 1st place which is not that much. 1/4 plate is overkill.