BTW! I was happy to find Yamaha MSN #394 for all 1973 models. Everything I've read and the videos I've watched on adjusting the oil pump, have shown the guide pin to be aligned with the line on the pulley when throttle is closed.

While my (181) pulley does have an index line, MSN #394 specifies that the oil pump guide pin should be aligned with the small round bump on the pulley and NOT aligned with the index line.

Please correct me if I'm wrong but I've already decided the '74 GT specs should be the same as the '73 GTs, and plan to align my guide pin with the bump rather than the index line..

ZT

It sounds like you've come across more than I have.  I've never seen an index that shows the bulletins cross referenced by year and model.  

I agree that the bump is what I would use, I have not come across that info for 1974 but both 73 and 75 GT80 used the same pump and use the round pulley mark and not the line.  

Biggest mistake on pump adjustment is not following the instructions on warming up, setting idle speed, and then taking up the cable slack in the throttle cable when checking pump mark alignment.  

Update, I just found the 1974 bulletin in a folder.