I just got these pics from Maico490t who has asked me to resize and post them.
Dave says "The pics I took are of a 82 GS 490 reed barrel on a set of 81 MC 250 cases Engine number prefix MT350. The same barrel dropped straight onto an 82 GS 250 set of cases. Interestingly in the second shot not only can you get a laugh from the piston size but if you look down you can see the two halves of the crankcase stuffers and the end of the rubber 'O' section compression seal - I tried to post these but the site said the files were too big so your help would as always be appreciated
" Like I said before, you learn something every day.