This post contains affiliate links maintenance XR-BAJA

Honda XR250 BAJA Seat Collar Replacement: A Generic Spacer That Fits (Sizes and How I Checked It)

Hello everyone.

The seat on my Honda XR250 BAJA (the Japan-market XR250 / MD30) is held on by two bolts at the back of the seat.
The bolts sit symmetrically on the left and right; the photo below shows the left one.

A metal collar is fitted here from the factory, but Honda doesn't list it as a separate part number, so you can't buy it on its own.
This time I managed to find a generic collar that does the job, so I'll share it here.

The left rear seat fixing bolt hole and seat base on a Honda XR250 BAJA

The bolt goes into the hole marked with the yellow arrow, but...

Close-up of the fixing hole in the XR250 BAJA's plastic seat base with the metal collar missing

Here's a close-up.
The seat base is plastic. Normally a metal collar sits in this hole.

The original metal seat collar still fitted on the right-hand side of the XR250 BAJA seat

This is the right-hand side. As the yellow arrow shows, there's a metal collar in the hole.
I'd removed the one on the left for a reason, thinking, "I'll just find a generic collar."

But I really struggled to find one that was exactly the right size.
These are the collar's dimensions:

  • Outer diameter: 11.99 mm
  • Inner diameter: 8.75 mm
  • Thickness (length): 6.08 mm

I measured them with a vernier calliper, so even ignoring the decimals, nothing was an exact match...
What I finally found at MonotaRO (a Japanese online industrial supplies store) was this:

  • Outer diameter: 12 mm
  • Inner diameter: 8 mm nominal
  • Thickness (length): 3 mm

I bought them thinking I could stack two of them.

The generic stainless spacers (12 mm OD, 8 mm ID, 3 mm thick) bought from MonotaRO as a substitute XR250 BAJA seat collar

They arrived from MonotaRO.
For reference, the product was listed as:

No-brand stainless steel spacer
8 × 12 × 3 (mm)

One 3 mm spacer pushed into the XR250 BAJA seat base, which is clearly not thick enough

I tried pushing one in straight away.
The outer diameter is a perfect fit. But, as expected, it's nowhere near thick enough.

Two spacers stacked to 6 mm in the XR250 BAJA seat base

Here it is with two of them in. A perfect fit!

Side view showing the stacked spacers sticking out very slightly from the plastic seat base

They stick out ever so slightly past the plastic of the seat base, maybe 0.1 to 0.2 mm.
I decided that this little wouldn't be a problem.

So the outer diameter and thickness are fine. The last thing to check is the inner diameter.
The seat fixing bolt goes through here, so this is a really important check.

Checking whether the original XR250 BAJA seat fixing bolt goes through the new substitute collar

I nervously tried the bolt, and it slid straight through!

Close-up of the XR250 BAJA seat fixing bolt passing through the substitute collar

Here's a close-up. You can see the bolt has gone through properly.

Comparing only the inner diameter, there's less play than with the original collar, so these spacers may even be the better option.
If you've lost one of the metal seat collars on your XR250 or BAJA, I hope this helps.

-maintenance, XR-BAJA