What fork seal fits a KTM 125 SX?

The KTM 125 SX uses a front fork that changed across model years: 45 mm (1993–1997), mm (1998–2002), 48 mm (2003–2010), 48 mm (2011–2015), 48 mm (2016–2022), 48 mm (2023–2026). We stock the manufacturer-verified seal and bushing kits for it; matching is done off the verified application list, not just the seal size.

What size is the KTM 125 SX fork?

The KTM 125 SX has a front fork that changed across model years: 45 mm (1993–1997), mm (1998–2002), 48 mm (2003–2010), 48 mm (2011–2015), 48 mm (2016–2022), 48 mm (2023–2026).

Can I use any seal with the same dimensions?

No. Fork seals can share a size and still not seat correctly in a different fork design, so use the seal verified for your bike. The kits listed here are confirmed by the manufacturer to fit the KTM 125 SX.

KTM 125 SX Fork Seals

Q: What fork oil does the KTM 125 SX use?

The KTM 125 SX uses 4wt fork oil, about 200 ml per leg.

Fork specs for the KTM 125 SX vary by year (see the table below).Every kit here is verified by the manufacturer to fit this exact bike. Fork seals can share a size and still not seat in a different fork, so we only list what is confirmed for your bike.

Years	Fork tube	Fork
1993–1997	45 mm	wp
1998–2002	mm	wp
2003–2010	48 mm	wp
2011–2015	48 mm	wp
2016–2022	48 mm	wp
2023–2026	48 mm	wp

Kit	Years	Seal size	Replaces OEM
55-114	2000–2001	43x53x9.5	KTM 43570623, KTM R14049
55-131	2003–2016	48x58x9.5	Yamaha 1C3-23145-L0-00
55-132	2017–2026	48x58x8.5	Honda 51490-MEN-A31, Honda 51490-MEN-003, Kawasaki 92049-0074, Yamaha 1C3-23145-L0-00
55-134	1999	50x60x10.5	n/a
55-135	1996–1998	45x58x11	n/a
57-105	2003–2026	n/a	n/a
57-106	1999	n/a	n/a
57-137	2000–2001	n/a	n/a

Verified fork kits we stock for your KTM 125 SX

Fork Seal Kit

Fork Oil Seal Kit — Gas-Gas EC250 (2012) + 174

$19.12

Fork Seal Kit

Fork Oil Seal Kit — Beta RR 2T 125 (2019-2023) +

$18.24

Fork Seal Kit

Fork Oil Seal Kit — KTM Adventure 640

$19.12

Fork Seal Kit

Fork Oil Seal Kit — Beta RR 4T 250 (2005-2007) +

$19.12

Fork Seal Kit

Fork Dust Seal Kit — Beta RR 2T 125 (2019-2023)

$19.50

Fork Seal Kit

Fork Dust Seal Kit — BMW F800GS (2013-2017) +

$21.01

Fork oil for your KTM 125 SX

A fork-oil change on the KTM 125 SX uses 4wt fork oil, about 200 ml per leg. We don't stock 4wt yet, so the closest weight we carry (5wt) is shown below.