Hi,I purchased what I thought was a BB gold star head on eBay a while back.It was as you described using only five studs.Also on closer inspection there were other differences such angle of carb inlet and number of fins.It had the same lettering(EX) as you mention.I returned it and got a refund.I really think this particular head must be from an early B34 competiton model and not a gold star.May even be late ZB competition.Did you get it on eBay?If so probably same head.
LightningPower: Here are your photos. I am of the opinion that this head is some sort of B33/34 conversion to alloy to match the B33 normal four stud pattern with an extra bolt up through the barrel to pull down the head onto the part that replace the pushrod tube of the iron top end. I would love to see the barrel it used. Actually the normal barrel would work if you kept the five bolts tight. I have heard of GS folks who do not always install all the bolts.
Without frequent roadside repairs there is no fun in riding!
I bought the head on eBay awhile ago. I'm guessing it was the same head that you bought. I don't have another BB head to compare it to, but looking at pics of other BB heads, both GS and Comp. share the same finning and use 8 studs.
So why the five stud head? Save weight? (but add to the risk of stretching the bolts) Early attempt at making this style of head? (which is unlikely because my earlier ZB heads are all 8 stud).
ZB34GS BB34GS DBD34GS Velo 500 Scrambler Other Junk
Hi,This is the same head I purchased.I had a BB gold star head in my possession to compare it to.There were many differences but it probably could be made to work.I remember it was much more robust and heavier.I think both the exhaust and the intake were angled differently than my BB head.
I just found a picture of a Gold Star motor with the same fins as on my head. It was on a documented 1954 350 Goldie that was built for the ISDT. Mine is 500 and not a 350, but at least the fins are the same! It can be seen on the link below "Retrorides"