What fork seal fits a Yamaha RD400?

The Yamaha RD400 uses a front fork that changed across model years: 34 mm (1976–1978), 35 mm (1979). 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 Yamaha RD400 fork?

The Yamaha RD400 has a front fork that changed across model years: 34 mm (1976–1978), 35 mm (1979).

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 Yamaha RD400.

Yamaha RD400 Fork Seals

Q: What fork oil does the Yamaha RD400 use?

The Yamaha RD400 uses 10wt fork oil (factory fill OE ATF/10W-30 engine oil (pre-fork-oil era); modern 10wt).

Fork specs for the Yamaha RD400 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.