Does anyone know the size of the 2 bolts that mount the headlight bucket to the mounting ears? This is for a 1975 DT250B part #97304-08025-00. I believe the size to be M6x1.00x25mm.


 

The sizes and other details are very often written into the part number.

In this case, the "08025" shown in the second set of five digits means that it is M8 x 25mm and the pitch is industry standard (1.25?).

Details on how to read part numbers are often shown at the front of parts lists or at the back of service manuals. Take a few minutes to search out any original parts list (I've found the ones for early models to be the most comprehensive) and have a read through what each character means. 

I have a CT3 apart and part# 97013-08025-00 is a M8 X 25MM. My DT250B's looks the same but did not pulled the bulb out to check.

I thought the diameter was a bit small but the length seemed right but now i know! I appreciate all the help and i will definitely be looking up how to read those part numbers.

If you don’t have a thread pitch gauge this Yamaha document will give you the thread pitch of all bolts used in assembly.  Everything after mid ‘68 is ISO.

 

I do have a thread pitch gauge but thats a handy little sheet! i think ill hang onto that lol i appreciate it!