2 sizes of cylinder base studs...??

My original cylinder base nuts were looking beat up and corroded, so I ordered new nuts and a few new studs. The new nuts are too large to work on the old studs because the old studs are shouldered to use a smaller nut. The bottom threads on both studs seem to be the same and they thread into one of the vacant stud holes fine. Also the hole in the barrel is wide enough to work for the larger diameter stud, so the new larger diameter studs and nuts should work fine. Is there any known reason why I shouldn't switch all my studs over to the larger diameter stud (and nut) ??? Thanks...

Without have to search through your posts, what bike are we speaking of?

Yes, 2 sizes. 3/8 x 6 pieces and 5/16 x 3 pieces on the 750. The pre 72 750's are different again being 26 tpi vs 24 tpi.

There are actually 3 different nuts. See 13, 14 and 15 here on the 72. There are 3 different nuts on the pre 72 also but different threads.
http://www.oldbritts.com/nor_comm_72_4.html

Pre 72 see 17, 18 and 19.
http://www.oldbritts.com/nor_comm_71_4.html

Living next door to Fred and Ella, you should know all this.

Fred and Ella have been a great resource for me. I ordered my base studs by the part #, so I got what I ordered... It's not their fault that I may have compatibility issues. I like the bigger diameter nut. I plan on checking to see if they will thread into my crankcase because my old 5/16th cylinder base nuts are mangled looking and I would like to change them all out...

Later this evening I'm going to back out a few studs and see whether I can swap my 5/16 shouldered studs for the newer 3/8ths studs I recieved. Then all I have to do is replace each stud and get the corresponding 3/8ths nut and I'm switched over to having

bigger nuts....

As it turns out, my '70 commando has 8 "stepped" studs threaded into the crankcase and one 3/8 stud correctly positioned in the front center of the crankcase. The two front corner studs are suposed to be the "stepped" 5/16ths version but the other 6 are suposed to be 3/8ths (they're NOT)

So... I got it figured out. I'm gonna remove the 6 incorrect stepped 5/16ths studs and put the correct 3/8ths ones in their place. I'm hoping none of those incorrect studs have been stripped previously and "JBwelded" in place...

edited to add: Thanks Pete!