Best way to bend this seat pan

Maritime

Well-Known Member
I realize they talked about this earlier in the thread. If you are bolting down the seat pan front and back it will be ok once on the bike but when apolstering it you'll have a hard time not distorting in and your cover may come out all wonky after you bolt it back down without something to take the flex out front to back. Side to side will be minimal.
 
I realize they talked about this earlier in the thread. If you are bolting down the seat pan front and back it will be ok once on the bike but when apolstering it you'll have a hard time not distorting in and your cover may come out all wonky after you bolt it back down without something to take the flex out front to back. Side to side will be minimal.
Yup, the clamshell problem is a concern, at least during upholstery.
I haven't decided what to do about that yet.

I am still debating whether to take it to an upholstery place and pay ... depends on my budget situation. If i do that, i might make some sort of jig, that replicates the frame so seat pan stays in the correct shape.
Not a lot of bike/car upholstery options here in BC, but plenty of shops that do boats ... will have to look into this more. I'll deal with it after i figure out the seat foam part.
 

Maritime

Well-Known Member
yes you could make a temporary frame that holds it rigid in the right shape and remove to install on the frame. A boat seat shop can do a bike seat no problem I am sure if you find one willing too. Marine Vinyl is a good option for bike seats.
 
I decided to skip the JB weld and just do a REAL weld on the seat bolts to turn them into studs. Did it with a 309L stainless electrode and it worked ok!

Also welded in a couple of tabs on the rear of the frame to hold the rear part of the seat pan down. Kept them so close to the frame I ended up having to cut down the wing nuts so they can fit on.

I'm just documenting my process here now (and will likely do a separate thread as well) so that it may help others in the future as I had a hard time finding good info on the DOHC frame before I started :)
Not intending to "show off" as there are much more competent builders on here

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Maritime

Well-Known Member
Since you can weld a few properly placed braces on your pan will make it less flexy for apolstery.
 
Since you can weld a few properly placed braces on your pan will make it less flexy for apolstery.
The more I think about it, the more I'm leaning to just a couple of "rails" of the same 18 gauge material cut to fit the profile of the pan and placed on top perpendicular and tacked in place along the pan.

Cutting long, thin pieces like that would be a pain in the butt though.
 

Maritime

Well-Known Member
Buy some small square tube. A few feet of 1/4" can be cut and welded into the right places and take all the flex out. On the underside or top doesnt matter but a few pieces in the right places and roberts your mothers brother
 
Buy some small square tube. A few feet of 1/4" can be cut and welded into the right places and take all the flex out. On the underside or top doesnt matter but a few pieces in the right places and roberts your mothers brother
Yeah I was playing with some flatbar, but it's not going to be as rigid as I want. We'll see what local place has for small tubing like that come Monday.

Not like the tubing has to follow the curve exactly to hold things together in the desired shape.
 

Maritime

Well-Known Member
exactly. just needs to be in a few places to take the flex away. and can be underside out of site or topside under foam.
 
Thoughts on finishing a brace like this? Bottom layer is going to be hard foam of the same thickness so I'm just going to cut it out in the shape of the brace and it should be unnoticeable

The only question: will it distort the shape of the pan when I weld it on? Opinions on this? I'd be tack welding this brace in about 5-6 spots, unless it becomes obvious it will need more than that

20200610_210947.jpg
 

CarbsAndCylinders

Careful With That Axe Eugene
Thoughts on finishing a brace like this? Bottom layer is going to be hard foam of the same thickness so I'm just going to cut it out in the shape of the brace and it should be unnoticeable

The only question: will it distort the shape of the pan when I weld it on? Opinions on this? I'd be tack welding this brace in about 5-6 spots, unless it becomes obvious it will need more than that

View attachment 226510
Could you rivet it to the brace instead of welding it?
 

Maritime

Well-Known Member
Rivets from the bottom would work fine. If you bury it in dense foam layer it should also not be felt either. Or even very long time between tacks and it should also be fine.
 
Could you rivet it to the brace instead of welding it?
I could, but i'm really liking that flat, smooth bottom of the pan that now almost looks like a fender. Don't want to ruin it with rivets, if i can avoid it.

Evne thinking what is the least amount of seat cover wrap around i can get away with so there is least amount of it visible on the bottom.
 

Jimbonaut

Well-Known Member
DTT SUPPORTER
What gauge steel are you using for the pan? The last one I made was 16 gauge, same bike pretty much as the one you're working on, same shape pan too, and it absolutely did not deform during upholstering.
 
What gauge steel are you using for the pan? The last one I made was 16 gauge, same bike pretty much as the one you're working on, same shape pan too, and it absolutely did not deform during upholstering.
18 gauge. Do you have some pics of the build for yours? I thought your last bike was a fibreglass pan, so i didn't even bother to ask.
But if its steel, i would love to see how you did it, if you have it documented somewhere on a thread, or instagram?

It does feel a little bit flimsy now. However, i do think that several layers of foam glued on would probably add to the stiffness a little bit. I don't want to commit to the foam, then find out it isn't enough.
 

Jimbonaut

Well-Known Member
DTT SUPPORTER
As I live and breathe. Rhonda, the old harlot. Miss that bike - if my shit gets together sometime soon then maybe I'll be swinging a leg over another CB750 in the not too distant.
 

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