Anyone know what the OEM stud sizes are. I'm a little unsure about the external thread pitch.
The thread going into the head is M8 with a course thread, 1.25 pitch. The external thread through the headers is M7 and a fine thread. Something like 1.00 pitch. Although one source mentioned .8 pitch.
I'd like to use something corrosion resistant, stainless or titanium. But would like to replicate the stock setup.
M7 Coarse is 1.0 Pitch
M7 Fine is 0.75 Pitch
Now it gets really interesting.
Do you want thread tolerance class 6g or 4g6h?
You can get both in either of the M7 Pitches.
(my guess is that the same holds for the M8 1.25)
6g means the same tolerance applies for the Major (nominal) Diameter, and the Pitch Diameter.
The Pitch Diameter is between the OD and the Thread Root.
6g allows for plating.
4g tolerance of the Pitch Diameter means a tighter toleranced threading indicative of a more specialized and critical application.
I have a feeling you will have a practical challenge finding multi thread size studs for a price you won't suck wind when you hear the price, maybe due to a minimum charge from a fastener supply house.
My guess is that the OEM stud is simple 6g tolerance at both ends.
As for Titanium Fasteners, as a rule they should not be used where anything over Grade 8.8 (roughly same as SAE Grade 5) has been applied.
High temperature anti-seize compound may be an easier route.
I think my interest in fastening started when I converted the cam tower bolts in my '73 SOHC CB750 over to SAE Grade 8 1/4-20 allen head cap screws. Then torqued the bolts to the bolt spec, totally oblivious to the fact that the cast aluminum cylinder head would be able to retain the necessary Helicoil inserts due to the bolt torque level. A rather sickening education that one was!