Have a 73 750 Commando and am going to check valve clearance this week. Is there a difference ins settings between the standard 750 and the 750 Combat head? I have a Haynes manual that says the Combat settings are different? What exactly should the spec be for both set ups?
it is a true 1973 model (and not a later '72 titled as a '73) then it shouldn't be a Combat, as Combat production officially ended during 1972 at serial 211110.
A '73 model 750 cylinder head usually has 'RH5' (std. comp.) or 'RH6' (high comp. but not as high as a Combat) stamped above the RH exhaust rocker inspection cover, if so, then it isn't a Combat head, Combat heads usually
have a 'C' stamp in the area beneath the head steady bracket, however the extra valve clearance is to suit the Combat 2S camshaft, and again, is something a '73 model wouldn't normally be expected to have as standard.
However, valve clearances are .006"In/.008"Ex for all standard models, and .008"In/.010"Ex for the Combat model.http://www.classicbike.biz/Norton/Repair/70up_Commando/70upCommando.pdf
Also, where can I find a reliable place to find std. jetting specs?
If you can give the carb build number (R/L 93? ??) that you should find on the raised pad of each carb, then I will probably be able to give you the original specification, as the manual
data is incomplete regarding the '73 specs.