The earlier reverse cylinder WR250/450 2016 onwards did have a proper extended steel subframe and rear light hanger/no plate
This was fabricated in Italy

before the bikes came to the UK
The rear subframe hanger was in steel and bolted to the existing alloy subframe and considerably ‘ beefed’ it up
The subframe and light kit was made by Spa Moto in Italy
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You might just see it if you zoom in on my old 2017 WR250F
You will find it on silver & black wheel rim 2016/17 bikes and maybe some early blue rim 2018 bikes
From mid 2018 onwards Yamaha UK bought bikes in from Japan instead and made them not fully road legal, so road registration was up to the owner instead, as they made them fully WR’s ‘closed course’ off-road bikes only & issued a certificate of newness only
Your best bet is to ask on uk Facebook WR forums to see anyone has one in the shed gathering dust (many people removed them) or try in Europe on Facebook WR forums (especially Italian ones)
You could also try DRD Yamaha in Norfolk as they are big Yamaha WR sellers and might have one in the spares department or Yamaha offroad experience in Wales as they might have removed them from 2016/17 bikes and not refitted them, when they sold off the bikes at the end of that season
You could try Spa Moto in Italy too
You could also try B&B Off-road in Oz as they do a huge amount of special parts for all dirt bikes and do focus on WR450F as the Oz market is the biggest sales market for the WR450F in the world
Shop high-quality motorcycle accessories and dirt bike parts at B&B Off Road Engineering. Built for performance, durability & adventure. Explore now!
bboffroad.com.au