Try our re-instated info resource - "Aladdin's Cave" (Main menu)- sorry it's taken so long to fix
If the thread pitch is 1.5, then ebay have then listed. eBay item number:114364359503https://www.ebay.com/itm/114364359503
If it's a genuine nut then why is it misaligned when torqued up? Something not right there Ted. So I looked on CMS because why would Honda used a flanged nut and a washer? I suspected the washer had been added later and shouldn't be there but no it's shown on the parts list. However look at it's specs, it's a 15.2mm x 25mm, why 15.2mm if the nut is 14mm. Is it meant to sit inside the fork slider not outside? The spindle is shouldered, does the washer fit the spindle on the shoulder or wider part. If so it's most likely meant to go against the speedo drive. Have a look and see if that might be the case.
When torqued up I can't get the split pin hole anywhere near.I guess a thinner spit pin is the answer as I don't want to overtighten it and strip the thread.I can see me replacing the special washer and nut, thats another £25.00 for DS.