I do not know a lot of details about this bike beyond that it had the rocket fast 1982 RM250 motor and i believe the chassis started out life as a Nickolson 1982 ATC250R frame but you can see a alloy swimgarm and the lower frame rails are nothing like a Nickolson so its been heavily modded by Eddie if indeed it is a Nicksolson frame and not scratch built.
The bike was super fast and Eddie got some great results with it against Team Honda and the other fast guys of the day.
Staging for a Pomona Fairgrounds Mickey Thompson in 83, George is in white and Eddie is in yellow..random Honda rider is slack jawed looking at what he is expected to race against.
The start of the 250 pro main at the Watsonville Offroad Nationals in 1983. Team Honda's Stevie Wright is #22 and he has Dean Sundahl right behind him, George is just behind Eddie and you can see Mickey Dunlop's blue #19 helmet just behind George...and yes Mickey raced his Powroll 200x against the 250s and did very respectable.
Eddie leading George, Chris white on the Tecate and i believe behind Chris is Honda's Marty Hart.
These are the only photos i have of Eddie's RM250 up close but you can see him on it in many of the picture of big races from 1982 and 83 that ill post if you look closely.
I cant answer a lot of questions about the bike but feel free to add or comment.