In 1992, whilst working at the 6 days in Cessnock , one of the workers had a multi hybrid CR/XR/XL that was actually registered (as a XL185).
If I remember correctly, it started as a XL185, then grow a big bore XR200 top end, then rebuild again with big cam and piston, then went into a stock CR125 frame, then worked the suspension, To cap it off he made all this stainless stuff to bling it up.
Sure on the transport sections it would have been a dog but I was told once he got to the single track everyone was minced.
I'll never forget the sound when he started it up. The crack in the exhaust was very similar to the moderns now. Sure it cost him a bomb, but fun was in the making it and making it go.
Would I do one of these Frankensteins, in a heard beat! Most of the fun is in the dreaming!
Peter B