Best way to cut seat foam

[MXP1MP]

I've never done this before so I was wondering if anyone has or known someone who has done it. From your experience what was the best way to do it? I'd like it to be as even as possible. I'm going to remove like an inch maybe inch and half mostly in the middle portion. Any tips on how to make it more evenly or tools used?
Thanks guys.

 

[DK]

I cut down and reshaped my DRZ400 seat and it made quite a bit of a difference. The stock tended to push you back and didn't allow me to comfortably touch the ground in awkward situations. Much better now.

I first marked the area I wanted to cut with a marker and then cut right off the top using an hack saw blade and smoothing it down with sand paper, starting with rough and using less coarse grades for a smooth finish. It's not as smooth as I would like, needs to be sanded further. If I was going to do it again I'd try cutting off against the bottom (against the seat pan), not the top. That way the top would keep it's original smooth finish.

 

[biglou]

Makita (and others, I'm sure) makes a small, hand-held electric belt sander. They work great for shaping foam. You may be able to rent one from a local rent-all.

Tips-Make your marks ahead of time and be patient and take your time. Neatness counts here!

 

[Patman]

Electric knife. Yup the same thing used on the holiday turkey. You can also perforate the bottom if you desire a softer feel (KTM guy here can ya' tell?). :D

 

[dirt bike dave]

Marking pen, large serrated bread knife and sandpaper is all you need. Well, and a stapler to get the seat cover back on.

 

[P_Taylor]

I have never tried this but I have been told this works well.

First , soak the foam in water

Second , freeze it

Third , cut and sand to shape while frozen

Fourth , de-thaw and dry out

 

[MONKEYMOUSE]

hot knife

My friend used a "hot knife" it worked good to make the main cuts. Then used a beltsander. Looks rather good. The hot knife made a bit of a mess:scream:. seeing how it melts the fome. But thats what its made to do:) .

 

[Bonehead]

The electric knife works the best and that's from a guy that has a 28" inseam

 

[DGMAX99]

I’ve reshaped a few using a right angle buffer with a sanding disc installed. A course grid works well. Clamp or block the seat foam stationary and don’t take big bites. Take your time and sand or cut very little at a time. The key to getting the shape you want and keeping the final result looking professional in patience! Lots of it! The electric knife works good to rough it in especially if you plan on taking off a lot of depth. The sanding disc (or belt as mentioned earlier) is good for smoothing and rounding off the edges. Or you can use the sanding disc to shape/reshape the whole thing. But remember, small amounts at a time! If you find small air pockets in the foam as you cut it don’t worry. You can further smooth the final surface by covering it with ¼” thick light density foam sheeting available from just about any crafts store. Just glue it to the final shaped seat foam with 3M spray adhesive. You can stretch it as it’s installed to take on the shape of the seat foam. This gives it an ultra smooth surface under the seat cover and fills irregularities but does not add any noticeable height because it compresses so much. Makes it look professional. Its also good practice to install a couple mils of plastic (like a heavy plastic garbage bag) between the seat cover and foam carcass to keep it from mildewing, especially if you have a seat cover that’s not black. Finally, rust resistant staples such as stainless or Monel work best to reinstall the seat cover. You can get them at Lowes. I’ve had the best luck using a T-50 Arrow manual stapler to shoot the staples into the plastic seat backing. The household electric staplers just don’t seem to have the power to force the staples into the plastic. An electric stapler meant for commercial applications should work. Heat the seat cover in the sun before reinstalling and don’t forget to stretch it tight as you staple it.

Good luck!
;)

 

[flogga400]

I recently cut the seat of an rm 80 down for my 9 year old nephew. He is a little short in the pants. I removed about 1 1/2 inches from the seat using the electric knife. It cut perfectly. Mark it carefully. Keep it symmetrical and it works out great. Don't mess with the other methods. This is the best way.

 

[BPracer]

flogga400-
when you cut the seat foam, did you have it on the bike or off?

 

[flogga400]

The seat was removed. I also removed the foam from the seat base to be sure I wasn't cutting it too thin. I marked it on both sides and cut away. I then covered the whole seat with gaff tape(kinda like cloth duct tape) and covered it with some stretchy vinyl. I kept it warm and pliable with a hair dryer. Worked real good on a tight budget. I have about three bucks in it and have enough material left to cover it again.

 

[flogga400]

By the way, this is an 84 rm 80 that I rebuilt for my nephew. It had one of the old cheesy tall flat seats. That allowed me to cut that much out of it and still have enough foam to be comfy. It even allowed me to kinda shape it up on the tank like a newer bike. The boy doesn't know he is riding an antique.

 

[BPracer]

Thanks for the info...;)

 

[Grok]

Originally posted by Patman
Electric knife. Yup the same thing used on the holiday turkey. You can also perforate the bottom if you desire a softer feel (KTM guy here can ya' tell?). :D

This is what the pros use, at least the upholstery guys I know.

 

[TexKDX]

I used a Stihl chain saw and wore a hockey mask.

 

[scar tissue]

a belt sander and a course grade flap wheel on a drill works good. It's easier to go slow with this method. You can sand evenly and it shapes smoothly. I've never had much luck with a knife, Of course I probrably didn't have the right one. It does make a big mes though.

I did it with the seat off the bike. I used the seat base to hold the foam while I shaped it. good luck