This dictionary came about because I was trying to find one myself and failed utterly, both on the web and in bookshops. It then became apparent that I was going to have to do the job myself. It's been compiled mainly by trawling Spanish-language biker websites, manufacturer's catalogues, magazines, etc, translating the content and discovering the English equivalent, often by a process of deduction (diagrams helped!).
I've added usage notes in places where they seemed necessary. I've not usually noted where a motorcycling usage is also an "ordinary" word. For instance, although I've translated "llave" as both "key" and "spanner" (because you might need both around a bike) I haven't included the standard translation of "estribo" (footpeg/footrest to bikers) which is "stirrup". This is partly laziness and partly because I figure most bikers can use a standard Spanish-English dictionary!
Please note that
Hope you find it useful!
English to Spanish / inglés a castellano
Spanish to English / castellano a inglés