Corbin Seat Overhaul



bigoltool

Registered
I bought my Corbin seat many years ago from a member here, who’s name escapes me . I have put many hours and miles on this seat and it has held up well save for some degradation of the mounting hardware; specifically the rubber isolators. I have noticed that in addition to the isolators, the seat foam was so hard that it was just transmitting more vibration than I was willing to deal with any longer to my ever aging ass. Additionally the shape of the Corbin left a little to be desired for me personally. The deep scalloping forced me forward into the nose of the seat, crowding the family jewels.

After pondering my options I devised (and executed!) my plan. I decided on a gel insert kit. But as I looked at the options out there I settled on the . This kit comes with their top o’ the line ¾” thick Gel pad, some really nice KP3 memory foam, and plenty of polyester backed smoothing foam to cover everything when done.

I intended from the outset to reuse the stock leather cover, knowing that it might not conform perfectly to the revised shape, as it is glued to the surface of the foam from Corbin. So my shopping list including the gel kit included a can of 3M #77 spray glue, a box of new 1/8” aluminum rivets to reinstall the cover, some new rubber grommets for the mounting bracket, and just because I was feeling adventurous I bought an oscillating multi tool from Harbor Freight.

I removed the mounting hardware and then drilled out all (~40) of the rivets on the factory cover, using a drill bit stop to avoid going through the seat and ruining the cover. Before I did that, I marked the centerline of the seat and the contact points for the seams with a Sharpie to help with the re-install. The Stock cover was seriously glued down to the foam and I had to steam it off with a clothing steamer (as is recommended by Kno-Place) which was a very slow and tedious process, to avoid destroying the foam and leaving chunks of it stuck to the cover.

I made a cardboard template of the gel insert on a flat surface, and then transferred it to the foam. I then took my oscillating tool and marked the cutting depth I wanted on the blade. This tool worked perfect for this, after trying to use a siliconed razor blade it proved far more precise. So I cut the outline, then cut it into 1” strips lengthwise and went about removing the strips. This is the trickiest part, as you want to wind up with a perfectly uniform cutout to put your gel into. So after removing most of the foam and even adding a bit more back in to get the shape I wanted, I switched to a surform shaper and my trusty 90 degree die grinder, with a sanding disc to smooth everything out. I also took off a bit of material on the outer edges of the seat that just didn’t fit me. Lots of test fitting with the gel pad here.

Next was to add the memory foam, I was trying to flatten the surface of the seat somewhat from where it started. After gluing it on I used my die grinder to smooth the edges and shape it to my liking. I also added a section of ¼” foam around the rear bowl to smooth things a bit more back there. Lastly installed the smoothing foam over the entire seat and I was pretty satisfied with the final shape. I again used the steamer on the cover before I glued it down and it worked great. From there it was just lots and lots of rivets all back into the stock locations with a couple of exceptions where extra tension was needed. I again steamed the cover to eliminate any wrinkles and applied a couple of liberal coats of Griots leather conditioner just for good measure. I knew going in that it would likely not wind up as sexy as the original cover but it actually wound up looking pretty good to my eye.

I put about 150 miles on it yesterday and I was pretty pleased with the result. The revised shape is perfect for me now, although in hindsight I would have taken even more off the outer edges of it, but that’s only noticed at a stop. The reduction of impact and vibration is noticeable! And the best thing is the reduction of crowding of the nads when coming to a stop.

The first couple of shots are the original seat with masking tape outlining the intended location of the pad.
ORIGINAL_LT.jpg
MARKUP1.jpg

BAD ISOLATORS.jpg
MARKED FOAM.jpg
INSERT.jpg
FOAM INSTALLE.jpg
SMOOTHING FOAM.jpg
FINAL.jpg
MVIMG_20180603_153427.jpg
 

mabupa

Registered
Great job! My genII Corbin seat always felt too stiff and the one that came with my gsxr tail conversion kit is even worse. I need to do something with it.
 

bigoltool

Registered
Great job! My genII Corbin seat always felt too stiff and the one that came with my gsxr tail conversion kit is even worse. I need to do something with it.
Yeah I can appreciate having stiffer than stock foam, but the foam in this seat is damn near structural. And it works for a lot of folks (!) so hard to fault them for it. That GSXR conversion seat looks awfully thin. The guys I bought my insert from make three different thicknesses of Gel, so I would recommend having a look at their site. My seat is fairly thick so it allowed me to go with the thicker insert. I just wish they would provide just a wee bit more of the memory foam. Other than that I am digging it.
 

Kiwi Rider

Registered
Excellent write-up and pics!
I bought a used Corbin seat for my Gen 1 a few years ago, it too was stiff as a board and too low as well as thrusting me forward with pressure on the gonads. Not good.
It also had the rubber support blocks on the underside NOT sitting on the subframe tubes, but directly on top of the battery ffs!
I used it a few times but didn't like it.
Sold it locally and got my money back ($180)
Put my stock seat back on and oh the relief lol.
 

ROADTOAD1340

Registered
I had one of those Suzuki gel seat on the L2 at one stage , ended up giving it to a mate in some sort of exchange . It raised you about 10mm higher which is good , but took too long to run in for my liking .
 

greg3852

Registered
Been thinking about refoaming my seat as well. It's a custom one that just needs some new life in it. Good info in the original post for some hints. Thanks.
 


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