How to Shave Your Dirt Bike Seat
Do it for the economics. Do it for the custom fit.
Just do it right.
I originally wrote this article for CRFsOnly.com’s form. It is a sticky on that site.
Since the original write-up I had taken photos of another seat that I shaved and incorporated some of them into a modified version of the article for this site. I have since made a few adjustments (last 03/20/2021) but I am sure there are some spelling errors or things that can be improved. Let me know if you see something that should be adjusted.
While this version does have the benefit of including current seat designs (low profile) and more details, the basic instructions are the same as the original how-to.
Get Your Head Straight
Shaving your dirt bike seat is a one-way ticket. You may be able to take more off, but you cannot put more back on. A shaved seat is a good alternative, or addition to, lowering your bike by using a lowering link or internal suspension work. I can pretty much guarantee that it will not look stock, and it will make your seat harder. If you have a KTM, the latter will not matter much as you are already sitting on a plank.
Shaving the seat provides a wider base that can be more comfortable than some stock width foams. It also provides an opportunity to roll the edges of the foam by sanding it for more custom fit, although you can do this without shaving the seat. The largest advantage to learning how to shave your dirt bike seat is being able to find the height that allows you to avoid tip-overs by being able to plant a foot, possibly even 2, on the ground or gain the additional room for movement you have been looking for without having to raise the pegs.
Having some additional clearance between you and the seat when things get rough is an added bonus. Learning how to shave your dirt bike seat is not for everyone and it can be costly if you mess up.
Before you proceed you may want to consider an aftermarket seat foam in either low, or soft. Durelle Racing, Guts Racing, and Enduro Engineering, and likely others, make some nice alternatives. I have personally owned seats from Durelle and EE. Both are high quality foams, but keep in mind that soft gel foams are heavier than stock seats but you simply cannot get more comfortable units.
If you are not interested in costly suspension work with the added penalties of lost travel and ground clearance, or, less expensive suspension options such as a lowering link and raising the forks in the clamps which still suffer the same lost ground clearance and can have a profound impact on handling, shaving your seat or a lower profile aftermarket seat are the options to be considering.
If you decide to learn how to shave your dirt bike seat there could be known and unknown costs beyond time, and there are no assurances that you will like a lowered seat. If you are working with an older foam, you may find it deteriorates or has de-laminated from the pan and needs to be replaced. While unlikely, you could uncover or potentially crack a seat pan.
Many aftermarket seat covers, especially the ones that come with the aftermarket seat foams, are not all they are cracked up to be and riders decide they need to purchase something different. If you are looking for a new cover regardless of the reason, you should be safe with just about any SDG or Guts season. Then you start getting picky and realize where grip matters or causes you grief, if ribs matter to you or if you can even tell they are there, etc.
If you are planning on buying an aftermarket lower seat but are just not sure if the lower height will be a benefit, go ahead and whack your stock unit down and see how if feels. If you manage to salvage the stock cover long enough to at least try out the new height you will be out nothing but time.
Should you decide to take the plunge and learn how to shave your dirt bike seat, take your time. It should go without saying, but you can take more foam off but you cannot put more foam on. Okay, technically you could add foam, but we will stay away from that one for this article.
Tools, Time, and Materials
This list seems a bit long but it is just basic items. Most of which you will likely have on hand. If you are comfortable working on things and use an electric carving knife, the process itself takes about 60 to 90 minutes of your time depending on how the cover replacement goes.
Note that I own a hot wire foam cutter and use it on other projects but the density of MC seat foam does not appear to be a good fit so I have simply not tried it. The electric knife is fast and cuts flat.
1. Get Uncovered
Unbolt and remove the seat and place it on a sturdy work surface. Hard and flat is better so you can slide it around. Over carpet could be bad because you are going to be pulling out a bunch of staples that you can easily lose track of.
Being careful to not tear or puncture the seat cover if it is going to be reused, use a flat blade screwdriver and lift up each staple. Ideally you should try to lift each staple evenly rather than only lifting one side. If you can lift the staples evenly they should pull out the remainder of the way by hand. If not use pliers and pull them out of the seat plan. Set the cover aside.
2. Top of the Pan
If you take too much foam off the pan you will undoubtedly split the foam. Suffice to say, this would be a very bad thing.
Poking the wire through the top will give you an idea of how much foam you have to work with but it is a bit difficult to visualize where you are going to cut by only measuring the depth from the top. You should do this anyway so you can approximate if trimming will even be worth it – note that even 1/2″ makes a difference.
If this is your first shave job I recommend you mark the pan by going in from the side at a 90° angle by taking a piece of stiff, thin wire and poke it through the side of the foam so as to find the top of the seat pan. Try to put the wire in straight, being careful not to wiggle it. Once you are sure that you have the wire straight in from the side and have found the top of the seat pan – it should scrape the top of the pan rather than bump into it –mark the hole for that piece of wire. If the wire missed or did not go in straight, no big deal just take another stab at it.
Once you find the top of the pan with one wire the remainder will go pretty quick. Make additional holes and marks as needed until you have marked the pan about every 4 inches. When you are done you should be able to look at the seat from the side and visualize where the pan is inside the foam.
Advanced route: If you confident in what you are doing, you can insert the wire from just about any direction and note the depth (wire goes down 3/4 inches, mark the foam at that height). Again, I do not recommend this for everyone as seat pans are / can be full of curves and impressions that give false readings. Entering from the side is without a doubt the safest and most predictable method.
3. Mark the Red Zone
You may decide to skip this step if you took the advanced route in Step Two
Using the ruler or a steady hand, connect all the dots from the wire marks with the permanent marker. If a mental note is not enough, use a color, write on the line, whatever, but do something to make sure to remind yourself that this is the depth of the pan and not the max shave depth. You ruined the seat before you got down to this depth if you managed to let your knife get down this far.
If you have a logo on the side of seat cover and want any chance of seeing it after you put it back on, you will need to mark its original location. The best way to do this is place the cover back on the foam, center it, and roll the side up until you get to the bottom of the logo. Make a mark on the foam indicating this bottom position, then continue to roll the cover until you get to the top of the logo, and mark that position as well. Make additional marks for the beginning and end of the logo.
You only mark one side of the seat when doing this. Marking the other side along with some explanation of pitfalls come a little later.
4. Cut Line
How you go about this will be personal preference. For me it comes down to the seat that I am working with. For the newer style (nearly flat) seats, precision is a must as the foam has very little give which translates to very noticeable/wavy cut lines if you are not near exact in your measurements and knife work. Experience says despite best efforts, one or both will be off. For the older style seats that lip up at the tank, you should have more foam to work with so you can be a bit loser with your marks.
For both methods I recommend you put the seat back on the bike. Take the electrical tape and mark the seat where you think you want to cut it. The electrical tape is flexible enough to make some nice curves and will not stick to the foam so much that it ruins the foam when you take it off. This process is a bit of trial-and-error and is very subjective to your preferences.
I strongly recommend you do not cut the front 3, or rear 1-2 inches of the seat foam for 2 reasons:
- The seams on seat cover, or sewn curves, will still fit as intended.
- Cutting to close to the edges, especially the front, will make taking the slack out of the cover very hard.
Once you have the tape where you want it, make a small mark every couple of inches on the “cut side” of the tape. The cut side is the side that you intend to shave down to, which for me is always the top of the tape. If you are not going the precise route, you can go ahead and just mark the entire tape before you remove it.
If you are going the precise route, measure from the factory shape lines down to the tape mark on one side of the seat, then measure the same distance on the other side of the seat and make an adjustment mark if needed. The point here is to make sure that you have marks that are the same distance from the factory shape lines on both sides of the seat. Once you have the measurement marks, go ahead and connect the dots.
If you have a logo mark on only one side of the seat you now need to estimate where the logo will land after you put the cover back on. Unfortunately all I can do here is provide a bit of guidance as it really is a subjective process. What I do is measure from the factory curve line on the foam to the top of the logo mark that I made on the one side then measure that same amount from the cut line on the opposite side and draw the logo location. Sometimes you need to decide if having the logo look good is more important than the shape of your seat. If in doubt and looks are important, get a seat cover without a logo.
5. Clean Shaving
Using a sharp knife, or better yet, an electric carving knife (best method), make thin cuts in the foam. Go slow so to avoid tearing the foam. Keep taking material as you work towards the cut line, being sure to stop before you are on the line.
Pay attention to what the foam is doing. Some parts of the foam will already have splits that require you to go really slow. This is especially if you have used the seat. Others will just split regardless of how careful you are. Just keep the damage to a minimum and fix it in the upcoming sections.
6. Make Some Dust
Before you start sanding, plan on saving some of the sanded material for filler.
This note was moved up and highlighted based on reader feedback as some missed it and a couple of you kept shop vacs going which resulted in mixing the foam with dirt (not good).
At this point the foam should be a bit choppy and shy of your ideal height. Translation, you have some sanding to do. To get started, lightly mist the top of the foam with spray paint. A fast-dry lacquer is best, but enamel will do. Try to keep from coating anything below the cut line. Let the paint dry to the point that it does not come off on your fingers and will not clog the sand paper. The dry time should be very quick unless you are working in the cold or used more paint than you should have.
Use 120-180 sand paper with a power sander (way better) or sanding block (so sorry) with the paint acting as a guide coat for sanding. As you sand, you will have parts of the foam stay colored while other parts become free of paint. The objective is to work the high spots until they blend with the low spots, while also leveling out the seat. Take your time and apply more guide coat if needed being sure to let the paint dry before you sand again.
7. Test Fit and Adjust
Now that you have sanded things smooth go ahead and put the seat back on the bike for a test fit. Pay close attention to the dimensions of the seat and note any areas that need to be sanded further. Now is the time to make any height adjustments. Also take note of the curving of the front and rear of the seat, and sand the foam to give it a nice contour if desired.
10. Round the Edges
You now will want to round the side of the foam so that it has a comfortable feel. Take the masking tape and tape the top of the seat foam a little bit inside from the new foam line. Unlike the electrical tape, masking tape will stick to the foam well enough so that it should not peel back when hit with the sand paper. The amount that you round-off is up to you, but I suggest 3/8-1/2 inch as a start. To make things easier I like to take a marker and color in the area that I want to curve, with the marker acting as the guide coat.
Once you have the curve marked, take the 60 grit sand paper and sand the curve by hand. Follow up with 120-180 grit to smooth things out.
11. If Your Crack is Showing
If you have small cracks in the foam, you can probably just leave them alone. For bigger tears and voids, gently score them with 60 grit sand paper then fill them with shoe goop (flexible glue).While the shoe goop is still very fresh, liberally cover the glue with sanding dust that you saved, and gently push the glue and dust into the crack/void. Repeat this process a couple of times while working in the glue/dust. Don’t worry about perfection. All you want to do is get enough of a mix in to keep the foam from having a soft spot later. The most important thing is to not make a tear worse. Top with a little more glue and dust if needed. As stated you can leave the small ones, only the big cracks/voids need attention.
After the fill dries thoroughly, hit them with some sand paper if needed.
12. Cover Up
If you had to fill cracks, do not start this step until the glue is completely dry!
When you staple the cover be aware that some angles will be harder than others. Keep in mind that it is better to end up with a stable that you have to push in with a hammer and punch than one that is too close to the edge and ends up poking through the foam!
Fit the new or re-fit the old cover onto the foam. Starting at the front, then rear, staple the cover with enough staples to ensure it is not going to get pulled off. Your staples should be about 1/2 inch apart. The initial stretch of the cover from front to back will put a decent amount of stress on the staples. Staples that are very bent should be removed and replaced in all cases, but here it is important that they get handled before moving on to avoid the cover slipping.
Once you have the front and rear in place, start about 1/3 of the way back from the front and pull the cover taught against the pan and staple it, followed immediately by pulling and stapling directly across on the other side. Now do the same except about 1/3 of the way from the back of the seat.
Now work forward and backward in both directions from these points, to the ends and the middle, on the seat repeating this pull/staple process. If needed, remove staples and re-position the cover.
13. Trim Job
Once the cover is secured, you may have a sizable amount of excess material to trim. Now is not the time to go primal and whip out the razor knife. The last thing you want is to slip past a staple and ruin that nice cover. Use a sharp pair of scissors.
If your seat has mounting tabs like the Honda cover shown, be sure to refrain from trimming too much around the tabs else the cover may roll up and expose the seat pan.
Install and Ride
That is all there is to it. Time to bolt that gem on and go ride!
First photo is a Honda with the old style seat. The second photo is a KTM with a new style seat. Both of the photos are the after photos of the seat foams shown in the article How to Shave Your Dirt Bike Seat.
The decision to rebuild the site from scratch was a decision to dump all comments that were on any article prior to the rebuild. While I am not aware that anything that should have received a response went unanswered, feel free to re-post if needed.