Reshaping the seat

It is possible to build up and reshape a spare seat for your Ninja to get it to fit you better. Get a spare seat off Ebay ($30-50 after shipping), some foam and glue ($32), and some vinyl and headliner foam ($38) to cover it. Find an electric carving knife (like Dad uses on a turkey). You'll need a staple gun and 1/4" staples. The goal of this project is to make a seat that is taller, allows you to sit further back, and is more butt-shaped for long rides. You can use your imagination and make any shape seat you need using this basic guide. There are custom seat makers who will be glad to do one for you, but this method will save you a lot of money.

Note that this method is primarily useful for adding height to a seat. To lower a seat, you would do the same thing described below, but without adding any foam. An important caveat for creating a shorter seat is that you are reducing the amount of padding under your butt when you do this, and that can lead to discomfort on longer rides. Rich of Rich's Custom Seats claims that a 5/8" thick gel pad is equivalent to about 2" of foam, and this might be a good way to go if your seat foam gets too thin. Unfortunately, seat gel is also quite expensive, so expect to pay US$50-100 for an appropriately sized piece of seat gel from an upholstery shop.

After you get the new seat, take the cover off it. If you're going to do this without a dedicated staple removing tool, use the thinnest, widest flatblade screwdriver you've got. This could be a good time to replace the cover. If you're radically changing the shape of the seat, going to a fabric store or auto upholstery place and getting a piece of four-way stretch vinyl of your choice is your best bet. If you aren't changing the shape too much Custom Seat Creations has a good selection of seat covers. You can e-mail them and see if they can help, and how long turnaround time will be.

Measure and cut a piece of 2" thick 5-pound rebond foam to cover the area from the front of the seat to the back of the main seating area, where it goes flat. Spray glue on seat and foam, and lay it down. After about an hour with the electric knife, you'll have the basic shape roughed out.

Take the bike for a quick ride with that seat and determine if it's close to what you're trying for. If not, go back and cut some more foam.

A few hints:

• Don't be impatient with the glue (this project used 3M 74 foam glue) -- really wait the full 30-60 seconds for it to set up before adhering the two surfaces together. It works a lot better.
• Don't rush the electric knife. Let it cut at its own speed, and you'll end up with cleaner cuts, and the knife won't overheat. These cheap consumer-grade knives need to be handled fairly gently, but they'll do the job in time. Using an electric knife is a hell of a lot easier than trying to saw through the foam by hand, and it allows much more creative freedom, as you're worrying about how the knife is angled rather than sawing back and forth.
• Be careful with the electric knife! Remember that electric carving knives are designed to cut through flesh on roasts and birds, and it'll to the same job on your fingers quite handily. It'll also do damage to the bike or its own power cord very quickly, so be very conscious when using it.

To anyone who's interested in doing this and trying for even cheaper, try checking local motorcycle junkyards for seats (or just operating on your own seat, if you can afford to have it out of commission for a week or two). Ebay is a good source, but the price can get bid up, and you usually have to pay shipping.

Check with local foam shops for big scraps, but it has to be rebond! Nothing else is dense enough to make a good seat. You might be able to find a shop willing to sell you a partially-used can of glue. A full can might be necessary if you have to do much regluing, but a partially-used can might be enough. You can also save money by getting the non-3M adhesive, which is about half the price but just as effective.

You should check with local auto upholstery shops for big scraps of vinyl that they'll sell cheap. If you can afford/find it, putting down a layer of headliner material (available at upholstery shops) over the finished seat between the foam and the vinyl really smooths things out and makes the seat look good when you're all done. Any thin foam would have the same effect, and buying 1/4" or 1/2" thick foam from a sewing or craft store could be cheaper, and they'll let you buy less than a full yard. Headliner or foam is mostly for looks, so don't worry about it if you don't care what the finished product looks like.

Your local thrift store with nasty kitchen utensils is a great place to search for an electric knife, and it'll probably even be cheaper than a decent new serrated knife or set of hacksaw blades.

Anyway, it's an interesting project, and it's one that anyone can do with minimal investment and some time. If you ride your bike for more than about an hour at a time, it can make the seat a lot more comfortable. Note that you can also cut down the seat if you want it shorter, and then you don't have to worry about new foam, or even a new cover, making the only investment that $7 electric knife and 1/4" staples for your staple gun.