Seat for my Honda CB750 K8

[seven54]

OK so it begins.

Here is the unfinished buck for my seat.

Thanks to LocO Leon for the Photobucket link and how-to.

Side View:

Rear view:

My Ride:

Basically designed it on Cad then made templates which were glued to craftwood and cut out with a jig saw.

Now all I need to do is foam fill it, shape it, bog it, sand it and seal it.

Any feedback would be appreciated.

Cheers

 

[locOleoN]

WOW...
thats the first seat/cowl set up that I've seen made from wood!!
Great Job so far!!..

How does it sit on the bike frame?.. I know that the cb750 frame is not perfectly horizontal flat...Doesnt the rear frame loop get in the way?

 

[HerrDeacon]

That is really cool. I've seen some concept cars done that way. Makes for a good way to ensure symmetry. I like the shape, should look good.

Keep posting pics of the progress.

 

[seven54]

That is really cool. I've seen some concept cars done that way. Makes for a good way to ensure symmetry. I like the shape, should look good.

Keep posting pics of the progress.

Will do HerrDeacon and thanks.

 

[seven54]

WOW...
thats the first seat/cowl set up that I've seen made from wood!!
Great Job so far!!..

How does it sit on the bike frame?.. I know that the cb750 frame is not perfectly horizontal flat...Doesnt the rear frame loop get in the way?

Thanks LocO,

I did take measurements before i started. The bumstop starts a fairway up the seat. Hopefully the thing will be OK.

Olddog's seat inspired me, and am using his tips as my guide.

Also, I have made the buck as wide as the original seat pan, hopefully I'll be able to use the original hinges and latch.

But, I've never done this before so it could end in tears

 

[seven54]

OK next step,

I enclosed the rear section in cardboard ready for the foam.

Then added the foam. WHAT A MESS. Wasn't ready for the result.

This is a two part Polyurethane Foam that sets hard. This stuff allows easy cutting sanding and you can apply BOG (auto filler) directly to it.
At first I thought I got a dud batch because I was adding the two parts together, mixing and pouring into mould but no foam. Turns out I wasn't mixing it for long enough. Mix it a good twenty seconds then pour and it goes off like a volcano.

 

[seven54]

Worked on it some more tonight.

Cut it up and roughly shaped it with my weapon of choice (a hand saw). Hard part about this step was cleaning up the mess before the missus spotted it.

So this is the rough form. Dotted line will be where I cut the cowl back so I can get a tail light wedged in there.

Next comes smoother shaping with a cheese grater file and then the body filler.

 

[lil beast]

Seat looks great. NIce work

 

[seven54]

A slight problem.

Bad for me but good for anyone contemplating doing this.

After i finished off the finer shaping with a cheese grater file, I noticed that the bumstop was no longer sitting evenly. One side had moved forward. When I measured this, the difference was around 7mm from one side to the other. So I cut the semi circular bit away from the foam and sure enough found the foam had expanded into the junction between the arched rear fins and the front semi circle. After I filed the excess away and put it back I also noticed the arched sections had come up around 5mm from where they were initially glued. I figured that the foam, which started off as a liquid, had flowed into and between the joins and then started to expand which forced the sections apart.

Next time I would seal all the junctions with silicone or paint to make sure the liquid could not get in between the joins. Now I have to cut the hump away from the base, remove the excess foam and glue it all back down with construction adhesive.

 

[Koestum]

Any more progress and pics on this seat project?

 

[seven54]

Any more progress and pics on this seat project?

I'm trying to get motivated, but it's hard with a wife the wants other things done, two kids and winter. But I will just have to make the time.

 

[boingk]

Hey, not a bad method. I'd definitely have a shot at that next time I need to make a seat, dredge out the old tech drawing board haha.

Anyway, if you're going to use bog I'd try fibre filler first and then finish off with styrene skimmer (often called 'lightweight body putty', look for ~150g/kg styrene as an ingredient). Fibre filler is basically fibreglass in a can, the base material being reinforced with thousands of fine fibres to help give good structural integrity when set. The styrene final layer filler is easy to use, lightweight and relatively strong once dried. It'll help take out fine holes, larger scratches and other imperfections in the fibre filler. You could skip the fibre stuff and just go styrene if you wanted.

Anyways, good idea for the seat and good luck with the rest of the build - boingk

 

[seven54]

Ok,

I have started "Bogging my Buck" so to speak.

raw seat

But in the mean time I had the original seat reupholstered (pics 1 & 2).

A mate of mine who works in the auto seat manufacturing business reshaped the original 30 year old foam for me and then i had it re-trimmed in black vinyl for 200 aussie smackers.

This will be my standby two-up seat that will do the business until I can get my arse (ass) into gear and finish the solo seat (pic3).

(pics 1 & 2)

(pic3)

 

[seven54]

Here's another pic of the seat from the same angle as the before shot at the beginning of the post.

And one from the top.

Here's my to do list:

1. Cafe seat (in progress) 2. Clubman bars (done) 3. Rear sets (purchased) 4. Powdercoat wheels black 5. Fit 18 inch rear rim 6. Bobbed rear fender and new front fender 7. Repaint tank black 8. Upgrade blinkers and taillight (purchased).

Cheers

 

[seven54]

Just a quick update on the bike,

Not really sure if I should post this here as it's getting a little old. But don't really know where else to put it.

Still no progress on the cafe seat. But have started shortening bits and generally making things smaller. Cut both mudguards back & added the rear tail light and blinkers. Next step is to paint the chrome and tank black for now until I settle on a colour for the tank.

Regards

 

[VonYinzer]

Gotta say man... That recovered original seat is terriffic. Really sharp looking.

 

[Nario]

Hey, not a bad method. I'd definitely have a shot at that next time I need to make a seat, dredge out the old tech drawing board haha.

Anyway, if you're going to use bog I'd try fibre filler first and then finish off with styrene skimmer (often called 'lightweight body putty', look for ~150g/kg styrene as an ingredient). Fibre filler is basically fibreglass in a can, the base material being reinforced with thousands of fine fibres to help give good structural integrity when set. The styrene final layer filler is easy to use, lightweight and relatively strong once dried. It'll help take out fine holes, larger scratches and other imperfections in the fibre filler. You could skip the fibre stuff and just go styrene if you wanted.

Anyways, good idea for the seat and good luck with the rest of the build - boingk

Wow this is looking good. I am actually inspired. i was not sure on how I was to approach building my seat but now i can see it coming together just like yours. Would like to see you finish it up thogh. Nice work!