The BASS linked rear brake/suspension tihng first came out in 1985, and was ditched by 89 (maybe 88?).
According to the tests of the day: They had a lesser engine than the CR or KX of the same year, the rear drum wasn't cool, but their biggest drama was that the suspension wasn't as good as the CR and KX (it was too harsh).
I'm still wondering whether an 86 CR or an 87 YZ would be the best 125 for the ACTMCC's "Old School" class, but given my excess of projects, and lack of time/funds, it it just a wondering.