I have had a look at the valve clearances on my Sprint engine today.
Now, I have never done this kind of thing before as I am used to tappets on old fashioned normal engines rather than this Sprint clever stuff with buckets and shims.
Consequently, I am not even sure if I am doing this right but if I am (see picture) then the clearances are way too tight. The clearance should be .46mm but I am finding between 0 (!) and .3mm.
Hmmm - time to think on