well i found a ebay seller with 1980 RM caps but he said they measure 25.7mm, that im sure is too big to be 25mm. my guess is they are 26mm and hes pressed real hard with the calipers and got 25.7mm. that isnt a common metric size i think suzuki would of used so im sure they are 26mm which would be no good.
Doc, dont you have some early 80's RM forks?