I bought a 1970 750KO new in April 1970. 38mpg around town and low 40's on the highway. 100% stock and I rode it Hard.
DICKL
Which is why I think there's a problem!
My 76 super sport got awful mileage, a PO had drilled the jets and the float levels were very high.
Though I've been trying to do most of the work myself, for various reasons, I sourced this batch of work to the cb750 "expert" in the Bronx. I suppose it is an assumption that he would set the floats correctly and do the jets properly, and I haven't taken them apart since I got the bike back two weeks ago. But gosh, this fellow came highly recommended and his whole shop was full of cb750s, cb550s, etc... like 40 or 50 of them. So I'm assuming he has a clue!
So now, in researching other possible causes of crap mileage, three culprits stand out.
1. leak: I don't see it. Well, not at the petcock, and I turn it off when I'm not riding.
2. timing: Could this bamboozle my mpg's this badly?
3. compression: boy I hope it's not this. This engine only has <35,000 miles on it and it seems to have plenty of oomph to it. I don't know how it was taken care of in the forty years before I got it though and I guess even a CB750 needs a LITTLE love over the years.
Am I missing any other suspects?