Differences in cylinder studs?

[markb]

Looking at my parts books I see that there are three versions of the two studs, -020, -030 and -040.  After deciding I’d like to use correct studs on E100, I found twelve 90033-300-030 studs (Bolt A, “long”) and four of the discontinued 90034-300-040 studs (Bolt B, “short”).  I compared them to the 2+ sets I had (less than 3 because I threw some broken ones) and saw that I had some that were thicker.  They measured about 6.1mm (.240”) and the new ones were about 5.6mm (.220”).  The thicker ones were definitely in worse condition (corroded) than the rest and after looking at pictures of my teardowns they are definitely off of E100.  So the thinner ones came from E1490 and E5491.  I haven’t removed the studs from E1789 and they’re thin too.  By the way, Wayne confirmed that his studs on E748 were also thin.

Then looking at the ones I bought I observed that the -030 longs were not plated and the -040 shorts were plated.  So I’m thinking that maybe the -020’s were thick, the -030’s were thin and not plated and the -040’s were thin and plated.  I kept looking and I happened to find another source that had 90033-300-020 studs and some more 90034-300-040 studs.  The -020’s (long) were in original Honda packaging so I am assuming they are correct earliest studs.  Ten of them were in the original paper in the bag and two were added to the bag.


But when I measured them they were thin too.  On top of that the -040’s (short) were not plated like my other -040’s were.  So much for my theory!  The good news is this second set I bought are in excellent condition (not a speck of rust) and they average closer to 5.7mm diameter and their unplated finish match even though they’re -020’s and -040’s.  I’m planning on using those on E100.

So my conclusions are:
1. The -020’s I got are most likely to be a correct part.  The other -030’s and -040’s didn’t come in a numbered pack so who knows what number they really are.
2.  E100 had been rebuilt with 1mm oversize pistons so maybe a non-stock heavier stud was also used.
3.  Early studs were not plated, later studs were plated.

Has anyone else noticed any differences in the studs?

[4pots1969]

Hello Markb,

I have an information concerning diameters for you and for all other
members who will be interested.

Only the studs of Honda CB750 F2 were increased in diameter of
5,60 mm has 6,00 mm because the power was increased has 73 HP. 

I personally equipped my Engine Sandcast of studs CB750 F2 6.00mm

Greetings,

Gérard.