70's KTM frames

[motomaniac]

http://www.ebay.com/itm/77-400-GS6-Penton-KTM-rare-frame-Vintage-MX-project-/170750871265?hash=item27c18b86e1&item=170750871265&pt=Motorcycles_Parts_Accessories&vxp=mtr

my question is what models used a frame with that type of backbone ? I have an MC5 and I had a 78 GS and that frames had 4 smaller tubes for the backbone not like this one.

[Slakewell]

These is the high breather frame were the frame is part air box looks to me to be as the add says GS 77 model

[motomaniac]

These is the high breather frame were the frame is part air box looks to me to be as the add says GS 77 model

so were all the GS's like that?

[Slakewell]

John Penton wanted them to be water prove so he developed this frame it was mostly early 75 to late 79 in some GS models. It.s hard to find the small 9 litre tanks that fits this frame if you dont want the huge tank as the MX dose not fit