Looking for Seat Mounting Advice

ridesolo

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I decided to start a category in this thread rather than put it into my build thread, thought maybe it might get more traffic here... who knows?

I'm trying to get things finished up on my long-running (too long) CL378 build so I can tear down, paint the frame, and then get it finished up once and for all. The question I have is if any of you might have suggestions about seat mounting or ideas about some kind of unique or special fasteners that might work for me.

As shown below I've got an electronics tray that's going to ride under the seat.

1232-090719110933.jpeg


Because of this, I can't come up through the bottom w/ bolts to secure the seat pan, I need to find some way to fasten it to the frame so I can get it off relatively easy when necessary but, of course, it needs to be securely attached otherwise. I had originally planned for an aluminum frame bolted to the bike frame that the fiberglass seat base would then bolt to. But doing that forces some way to remove the upholstery to get to the bolts. The guy who's going to do the upholstery wants me to come up w/ my fastening so that he can then work around it when doing his work. Though I didn't originally want the common snap fastenings along the sides and up over the hump I had pretty much conceded to that plan but he says that depending on my solution me may be able to come up w/ something that will eliminate using snaps.

I have some stiffening bar mounted on the bottom for stiffness and proper spacing/positioning, that's the button heads you can see in the pix below. Also there will probably only need to be one fastening on eash side more toward the rear as the front will be held in place by a metal tab.

1232-090719111108.jpeg


Anyway, one idea I've come up with is to put holes through the side of the seat base into a tapped hole in the side of the frame rail. I'd have to use spacers between the fiberglass and the frame to prevent squeezing and cracking the 'glass and deforming the shape. Pix below shows the relationship between the 'glass and the frame rail.

1232-090719111246.jpeg


If I went this way I would probably use something like an elevator bolt like show below to take advantage of the flat profile.

1232-090719111339.jpeg


So, does this seem like a workable solution? Am I too close to it and over thinking it, making it too difficult? Are there some kind of fancy fasteners or something out that that would help me out?
 
Do you have something tying the frame together from side to side, where you cut it off? That thing's gonna flex like crazy if you dont.
 
scott s said:
Do you have something tying the frame together from side to side, where you cut it off? That thing's gonna flex like crazy if you dont.

Don't think so, there's nothing back there but my own weight. the engine cradle and forks/swingarm/suspension mounts are all supported.
 
Agree w/ Scott. You need some kind of cross-member at the rear of the frame. Cafe builds often use a loop for this, but you could just use a solid brace if that's easier.
 
Psychopasta said:
Agree w/ Scott. You need some kind of cross-member at the rear of the frame. Cafe builds often use a loop for this, but you could just use a solid brace if that's easier.

Thanx. If it comes to that I'll make changes, but it's been discussed and we're comfortable that it'll be ok. There's nothing back there but my weight and the seat and electrics. Remember, most of those adding a loop still have their twin shocks that have to tie into something solid and non-flexy. Even my foot pegs are tied to the main loop and not to the rear sub frame. If I were to shore up anything I'd be better off putting something between the top, right under the end of the tank, of those two vertical frame tubes behind the engine. That's a known possible flex spot on a 360. I'll be keeping a careful eye on things there and will reinforce if necessary. We've also added a very solid brace between those same two tubes right above where the top of the monoshock mounts.
 
There are a few options. One is to weld a couple of mounting tabs on the top frame rails and bolt trough the seat into those tabs and make a seat pan retained by velcro to cover them.

Or you could fabricate a front tongue that located under the tank somehow, and have a single or twin bolt rear mounting - minor welding still involved
 
Your weight is the heaviest unsprung weight on it, and when you hit a bump will really stress a poorly supported seat. If roads were all smooth, flat, and dry we wouldn't need suspensions and fenders.
 
pidjones said:
Your weight is the heaviest unsprung weight on it, and when you hit a bump will really stress a poorly supported seat. If roads were all smooth, flat, and dry we wouldn't need suspensions and fenders.

If I'm sitting on the seat I'd better be sprung weight! Last I knew unsprung weight was the stuff below the springs; wheels, tires, etc.

It'll be fine as-is. I will, however keep an eye on it as I said, and if I see any signs of stress the good Mr. Hurco550 and I will do all due diligence to rectify and improve.


teazer said:
There are a few options. One is to weld a couple of mounting tabs on the top frame rails and bolt trough the seat into those tabs and make a seat pan retained by velcro to cover them.

Or you could fabricate a front tongue that located under the tank somehow, and have a single or twin bolt rear mounting - minor welding still involved

Thanx for the reply. Actually this was a pretty old post that I probably should have deleted when I decided a while back to use the second option that you made, a sort of a tongue affair at the front and then two small bolts into the frame at the rear. I had originally planned to set it up like the first suggestion you made, but doing that would have had the line along the bottom of the tank and seat off. By putting it directly down on the frame I get a nice even line along the bottom of the tank and seat.
 
GSXR, Ninja, Katana, Hayabusa, etc pillion seat latch assembly. I use them on most of my bikes. It's all you need to mount the seat, and it gives you a remote cable to disengage the seat.

s-l1600.jpg


s-l1600.jpg
 
irk miller said:
GSXR, Ninja, Katana, Hayabusa, etc pillion seat latch assembly. I use them on most of my bikes. It's all you need to mount the seat, and it gives you a remote cable to disengage the seat.

Not a bad idea... if I had more room.
 
irk miller said:
You do have room, but if the thread is old it doesn't matter anyway.

Yeah, and since I really don't have room (my bike that I'm building and am intimately familiar with and I've seen those mounts before so I ought to know), I don't have a need for quick assess to the area, and it's an old thread, it doesn't matter anyway, does it? But I appreciate the additional two cents worth. ;D

EDIT: Oh my, how uncharacteristically testy of me! Sorry all, guess I just got irked. (probably) Won't happen again.
 
It's amazing how easy it is to misunderstand an OPs intention or tone in a thread. We all tend to write in a form of shorthand and sometimes others read something into what we said that we didn't intend.

It's all good. We can do this.
 
Didn't mean anything by my post. I've used it in a similar applications, so I figured there was room. After I read through the thread again to make sure I wasn't seeing something I missed after the "don't have room" comment, that's when I read the post about it being an old thread. I appreciate having a nickname shared only by friends and my wife used in such a respectful way, though. I'll remember at Mid-Ohio. Besides, a Google or DTT search by someone typing in "seat mounting advice" can likely bring up this thread, so the information may be valuable to others. I try to consider that when offering input on these threads.

I'd say I've used this mount on at least 6 bikes. I replaced the mount on my BMW /7 seat with this set up, as it's not just about quick access, but just a clean hidden way to mount a seat. It's the only mount on that /7 seat, and the seat is super secure. The stock mount on those seats kind of suck, so it's actually an improvement. I like it because it requires no external hardware. No rear or side screws or anything like that. It's totally hidden. The remote cable, which if you buy the key latch, can be be a security thing too. The Moto Guzzi I had in my shop last month has a keyed lock for the cable release just above the left foot peg. This latch works with that keyed lock, so no one without a key would be getting into that tray.
 
Nice mounts and handy to be sure. The next build, IF there is a next build, will be a somewhat larger bike that will benefit from access to underseat storage. Unfortunately my days of long-haul riding are behind me; at one time I could have been a poster child for the old Johnny Cash song, "I've Been Everywhere." In thoughts, planning and keeping eyes open for the next build I've yet to find the balance between simple; fewer carbs and cylinders, etc., large enough to ride good and be comfortable for a few hours but small and lightweight enough for a guy over 60 to move around the shop/driveway/parking lots, lots of power; under 750cc and certainly under 500cc ain't gunna cut it. Guess we'll just have to see.
 
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