I happened upon a KTM technical service bulletin dated 4/26/79 that I bought from Donny Smith a while back when needing some of the specifications and information that pertained to my 1980 MC 250. I have previously questioned the fact that my 1978 250 has A MX6 side panel decal, and found in this bulletin under the fork oil capacity chart that KTM had listed 1979 125, 175, 250, 400 & 420 MC80 models, and also a MX6 designation for the 125,175,250 and 400 bikes.
I guess that means that the MX6 designation actually exists, but the decal on my 1978 250 may have been a 1979 decal, as the referrences made in this bulletin referrs to 1978 as only having a MC5 or GS6 designation. Mike
Michael R. Winter
1974 250 Harescrambler
1975 250 HS Project
1977 250 MC5 Project
1978 250 MX6
1979 250 KTM Project
1980 250 MX KTM