[richlandrick]

The three way to make something stronger are use more material, use a stronger material, or use a stronger shape. Those bends at the edges of the aftermarket 1/8 plate add strength. 3/16ths inch of any aluminum alloy you are likely to come across is going to be fine though. Be sure to spread the force at the back where it mounts to the factory rack using sandwiching plates to spread the force transferred to the resin rack. You probably knew that though.

 

[DesertBike]

I think that's what the Givi SR3112 kit does. There are two lengthwise sheetmetal pieces that are sandwiched between the spacers for the SRA3112 plate, and the factory rack. I expect they spread load as you mention.

The side support arms act to further spread the load, transferring some of it into the attachment points for the factory side cases.

Basically, I am doing a straight replacement of the Givi SRA3112 adapter plate with my own adapter plate. My plate will have several sets of holes for the 4 bolts that secured the SRA3112 plate, so that I can mount the plate (and thus the top case) in 4 different positions, progressively further back in 1-inch increments. Here's how I have the plate marked up for drilling:

 

[DesertBike]

Had a nice long talk yesterday with the buddy whose tools I'll be borrowing to complete the project.

He does have the stuff to do countersink holes for the 4 major bolts. We also discussed using a stepped drill to make uh...what do you call a countersink that is purely cylindrical rather than cone-shaped? Possibly an option as the plate is thick enough.

RevZilla was really fast. I ordered the "mushroom" Monokey studs (Z125) just 2 days ago, and they're already here.

 

[DustyBoots]

I used some countersink bits on my 3/16" AL plate.
Like you said, it's plenty thick enough

Dusty

 

[DesertBike]

Dusty, were you thinking of painting your aluminum work or are you going to keep it bare?

I thought about hitting mine with a couple of coats of Krylon Fusion, once all the drilling and edge finishing is done. I have some of the matte black type.

 

[DustyBoots]

Dusty, were you thinking of painting your aluminum work or are you going to keep it bare?

I thought about hitting mine with a couple of coats of Krylon Fusion, once all the drilling and edge finishing is done. I have some of the matte black type.

Seeing as spray paint doesn't adhere all that well to AL, I am just going to let it age to a natural 'Patina', as I will have the top box, or a duffle on it most of the time.



Dusty

 

[DesertBike]

Good point. A primer would likely be needed, at which point it turns into a whole project.

Powder coat would be nice, but likely to cost more than I'm looking to spend. I'll keep the aluminum bare.

The alloy (6061) is supposed to be corrosion resistant, so natural patina should be fine.

 

[richlandrick]

Countersink for bolt head is called a recess, as in recessed hole.

I have often thought this kind of thing would make for a great community project.

 

[DesertBike]

Countersink for bolt head is called a recess, as in recessed hole.

I have often thought this kind of thing would make for a great community project.

You know what, I think that's kinda what's happening, and I'm happy to be part of it.

We have a lot of well-meaning folks trying to convince me to go with prefab solutions on the first page, but I wasn't smart enough to listen to them & take the easy path. Should be an interesting journey.

I'll share my results as I go along, and if anyone has questions about the process, I'll do my best to answer.

Maybe someone with access to CNC machinery could make a file to churn one of these things out in a hurry. It's fairly simple. 3/16" 6061 T6 aluminum plate, with appropriately-spaced holes of various sizes. That's pretty much it.

Then you have to buy the Givi Monokey mounting pieces. Most economical way is probably the Givi E115F kit. Includes the two "mushroom" studs and clicky gray wedge hardware, plus screws and nuts for same.

 

[DesertBike]

There has been significant progress!

Went out today and bought a few simple tools to help me drill as accurately as possible.

I talked it over with the buddy with the drill press. His table can't handle a plate of this size.

He convinced me that I could do a good-enough job drilling by hand, so that's what I'm going to try.

I needed new drill bits in general, so I treated myself to a set of new cobalt alloy bits. Overkill for drilling aluminum, probably, but they should last for many years and projects to come.

I have the plate marked up, and the places where the first few holes will go are marked with an automatic center punch. Plate is clamped to a work table. Just have to do the actual drilling.

Once the holes are done, I'll figure out how many of what size nuts & bolts are needed to secure the Monokey "mushrooms" and wedge. Then...the True Test...I see if one of my spare Monokey cases will actually fit securely!

 

[DesertBike]

All holes drilled. Still need to do countersinks, or recesses, on the four support bolt holes.

Also, need to test fit on the bike in place of the SRA3112 plate to make sure I got the hole spacing right.

The hole spacing for the Givi Monokey hardware is fine. There's a little slop built into the Monokey system, so I didn't need aerospace-grade precision.

 

[DesertBike]

I went with countersinks.

Unfortunately, they're going to be ugly, though functional. I ran into 2 problems:

1) Metric screws meant to be countersunk use a 90° head angle. The most common head angle for SAE/non-metric screws is 82°. You can guess which one was the only type countersink bit anyone had in stock.

I didn't want to wait a week for a 90° countersink bit to arrive, so I bought the 82° bit. It should work fine. From what I read online, you have more trouble putting a US screw into a metric hole than vice-versa, because the steeper slope of the metric countersink means there is very little contact area with the screw head, and it's all near the rim. You can even snap off screw heads due to this. With the metric screw in US-slope countersink. the screw will make contact nearer the shaft and bottom of the countersink.

2) It's impossible to drill a clean countersink by hand, or at least I can't. Both of my holes so far started clean and circular, but increasing chatter has caused one to come out like a rounded hexagon, the other a more interesting shape (decagon?) but with irregular sides.

I've experimented with various combinations of drill speed & downward pressure, but it seems like chatter is unavoidable.

Not nearly as pretty as Givi's countersinks, but should work.

I did consider doing recessed screws, but I felt like there was more room for error with countersinks.

I think I can live with the ugly countersinks. I won't see them 99%+ of the time.

 

[DesertBike]

BTW, the right countersink (second one, I'm still working on it) isn't skewed like it looks here. That's just from having the camera close to the plate and more lined up with the left countersink (first one I drilled).

I counted - somehow I made an 11-sided scallop. Weird. Pretty sure the countersink bit has an even number of flutes. There's probably some disgustingly abstruse vibration mechanics equation that would explain this.

 

[oldjeep]

For future work when using hand drill. Start with a centering bit. Drill countersink first with standard bit, drill through hole second .

 

[DesertBike]

Huh? Standard bit doesn't have the right tip angle to do a countersink. The cobalt ones I bought have a 135° tip angle for instance. Older plain steel ones are about the same.

Supposedly the type of countersink bit where it's got both the twisty piece to drill the hole, and the countersink part farther up the shaft, works better for hand drilling. Oh well, lesson learned. I don't think I'll replace this "prototype" just so the countersinks are prettier though. Too much work, unless I get a drill press in the meantime.

Pitchers to follow. Going on a test ride in a minute.

 

[DesertBike]

Plate mounted in place of the SRA3112 adapter.

Side view. Scoots the top case back 3" compared to original setup.

Fit is snug. Doesn't rattle when riding. No sign plate flexed during the test ride, which it shouldn't since I have very little in the top case while riding. It only holds significant weight (helmets) when parked.

Success so far. I'd like to round off the corners more, but that can wait until I have a way to do it neatly.

 

[oldjeep]

There are a variety of bit tip angles available, but when I countersink in steel/aluminum I am not using tapered screws - I use flat backs.

 

[DesertBike]

Gotcha. I went with countersinks with this, mostly so I could easily re-use the existing hardware (so-called flat head metric screws, having a tapered/conical head profile). Seemed wise to stick with

It's likely there would have been enough plate thickness to do a recess for a button head screw. Something to consider if I wanted to do another one of these. Or if anyone wants to copy my design, which is OK by me.

The hardest part of the whole project - besides drilling the countersinks - was locating holes accurately. Somehow the holes for the Monokey hardware (2 mushrooms and wedge) ended up offset about 1/8" to one side. I can only tell when looking at the plate from below, with the top case sitting on it.

I'd still like to chop off the plate's corners. I did round off the corners a bit using a hand file. Ditto for the edges of the plate. All were fairly sharp at first, with one having a small flange left over from the cutting process.

 

[DesertBike]

We did a test ride with the new top case position. Much much better. We could actually stand to be on the bike long enough to find other problems.

She was much more comfortable except that her knees were too bent. It seems as if Suzuki moved the passenger footpegs up and back vs my old Vee. Not sure if there's any way to fix that.

Suspension was a bit overloaded with two of us. However it wasn't nearly as bad as the stock suspension on my old Vee.

I don't think I'll spend a couple thousand bucks trying to make the DL650 good for 2 up, mainly with suspension upgrades. I think instead I'll follow through with the idea of swapping to a Yamaha FJR 1300. We're going to go do a test sit on one this afternoon. Nobody is going to let us do a 2-up test drive, which is understandable, but just sitting on one should help.

 

[richlandrick]

Most countersunk bolts use a 45 degree head angle. Countersinks are available in a variety of head angles, but they all need to be used at low rpm to get a smooth finish.

The DL650 can be an excellent two-up sport touring machine with minor modification. Just stiffer springs front and rear, with rear rebound run completely full and then back off a 1/4 turn and fork brace made a hug difference for us. I combination transformed the bike.

Of course the seat becomes limiting, but a seat concepts seat kit will fix that.