Have you looked at the reed valves? You should only be able to blow air through them...ie you should not be able to 'suck' air through them. Visually you should see they are flat and sealed against the reed cage...or very close to it
Strip and clean the carb again and blow out all the passageways and jets within it, did you take out the needle jet (aka emulsion tube) when you cleaned it?...
Have you got a Haynes manual Steve, I documented a pretty 'in depth' check for the DT175MX, if you substitute the figures for the coils of the DT50 it may be of use to you?
What an absolutely stunning bike you have resurrected there, I know it was in pretty good shape to start with but hey...now it's like new. :eusa_clap: Well done Ventura.
Are you keeping her then?
However the lever boss will be limited to fewer 'smaller' models probably due to the smaller diameter splined shaft, so getting this is 'key' to having a kicstart...the lever itself will no doubt be easier to find. I found a 'boss' see your intro post
Greetings and Rik, nice to see such enthusiasm for the little old stroker
http://compare.ebay....&var=sbar&cbt=y
http://www.ytcn.nl/a...L 1950-1996/RS/
Any use? from what I can see the lever is used on many bikes, and I mean...many
http://www.ytcn.nl/archief/index.php?dir=Yamaha%20Parts%20Manuals%20ALL%201950-1996/RS/
How about an intro in the appropriate forum Rik?