Thanks for purchasing the MT-09 Seat slope mod for the 2021+ 2021-2023 models. This includes the Gen 3 and Gen 4 models of the Yamaha MT-09. This is an early version of these instructions and they will be updated with lessons learned from customers as this product ships more.
The install of this kit should be straight forward with only 4 or 5 bolts to be removed and put back in.
What this kit does – it shims up the Tank/Seat forward bracket by 6-8mm to level out the front of the seat. Since the Seat and Tank are supported by the same bracket, I include some eccentric rubber bushings that can be used (not required) to keep the tank lower close to its OEM height.
Area we will be working in on the bike: (click on images for bigger sizes in this document)
Important notes / Tips before you begin!
- Early Batch notice (kits shipped before 2/10/2026) – some kits were shipped without 8 washers and only with the 4 big fender washers, please email support@jk3d.us for the missing 4 to be mailed out or a refund for $4 to buy them locally.
- Do this install with the fuel tank mostly empty!! – Since we will be unbolting the rear of the tank, most of the tank weight will be back there. The tank will rest on the frame and you will need to pick it up to align with the bracket after the install. A full tank makes it feel like the tank wont move. Most support emails I get are from the tank being too heavy to lift.
- For the Gen 4 MT-09, Please email Support@JK3D.us A fitment compatibility has been discovered. Please email before installing, I will also be proactively reaching out.
- Take photos of everything before you start, this is just a good mechanics trick to remember how stuff looked, and make sure nothing is missed.
- Note: Some photos are from pre production runs some minor items have changed like the top washers for the bolts are now shipping as small washers instead of large shoulder/fender washers.
- Tools Required:
- 4mm Hex Wrench
- 10mm socket/wrench (for Gen 3 models for the tank bolts)
- Blue Thread lock compound (Optional, but recommended)
- Torque Wrench (12Nm for the main bolts, 7Nm for the fuel tank bolts)
Basic Layout of the install:
Note, for Gen 4, you may need to place the rubber eccentrics backwards with the flange side toward the seat if there is clearance issues getting the seat to align.
The install has 2 parts – the Seat Bracket shims and the eccentric bushing for the tank alignment (lowers the tank by 3-4mm when the seat bracket goes up by 6-8mm). You can see in the Gen 3 image at the top of the page how the eccentric bushings work to offset the bolts down in the holes.
Install Steps:
- Set the bike on a bike stand, center stand if equipped, or side stand. Note: side stand makes this more challenging due to the tank rear wanting to shift to the downhill side.
- Unbolt the 2 tank bolts and remove the metal sleeves (retain these as you will re-use them) from the OEM rubber bushings (you may support the tank with something non scratching like wood blocks if needed to keep the tank from sinking onto the frame.
- Unbolt the 4 seat bracket/frame bolts. Retain the OEM bolts in case you want to return to stock, but they wont be used in this kit.
- Take the bracket off the bike and push out the OEM rubber bushings, and insert the ones included in the JK3D kit back in, with the extra rubber flange on the bushing toward the tank (as shown in the image above). Ensure the eccentric bushings are aligned with the offset hole being at the 6pm (at the bottom) position. Shove the OEM Steel sleeves into the bushings.
You can now do the steps in Option 1 to install the seat shims.
- Set the seat/tank bracket back on the bike and align the tank to the bracket. Reinsert the OEM tank bolts and Torque to 7Nm.
- Assemble the frame shim stacks as the images at the top of this section show – fender washer on top>6mm shim > 2mm shim (optional)
- Gently but firmly grab the center and slide the shims under each side, this works best if another person helps just due to the weight of the tank, but it can be done just with one person.
- Insert the 6mm bolts included with the kit with 4x washers on them into the holes and start threading them into the frame by hand and tighten them just snug for now.
- Insert the seat as normal, and look at the alignment and see how the seat feels sitting on it. (For Gen 3 bikes do NOT use the upper slot when installing the seat bracket by accident, that can use the seat to be unstable)
- If the alignment is good and the shim stack height is what you want, one by one take the 6mm bolts out, (optional) add a small dab of blue thread lock (DO NOT USE red permeant thread lock), and then torque down to 12Nm. Work in a cross pattern across the bracket making sure its centered on the frame.
- If the alignment is NOT ok and you want to make a change: Take the bolts out and remove the 2mm shim if the stack is too tall and then redo-the above, and if the tank is lifted too high go to Option 2 below.
- Get your gear on, and go for a ride!
Final checks and considerations
You may need to tweak your bar angle with the updated seat alignment to adapt your wrist/arm positions. Do some testing and tweaking.
After a couple months of use in hot weather I would check the bolts on the frame/seat bracket to ensure no play.
As always, if you run into any issues, concerns, questions, or feedback please email me at support@jk3d.us and I will work with you directly on addressing any issues you run into.
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