Thanks Adrian. Question KTM boys...My 1976 250 MC5 motor and a 1978 250 GS motor, whats the same/different??Are MC/GS 250 54 cases the same. Will internals swap over? Rather than chase a barrel ,the whole motor option might be better. I contacted the above ebay items,asked about condition of bore etc, contact stopped,no replies. Also looked into getting bore liner made...thats a possible option. So now a GS motor come up,so hence the question...are they the same?