Cylinder cut outs in the cooling fins.

[ziggy stardust]

Can anyone explain why some 350s have two neat cut outs to their cylinder fins on the outside and some don't? Just curious.

Z

[moonpup]

Well, I was going to say maybe it was a difference between the GTR and the GTO, as both my GTO's have the cut outs and most of the GTR pics I've seen don't. However, I was recently sent this pic of a GTR with about 1000 original miles on it before they blew the engine and stuck it in a barn for 40 yrs. It has the cutouts.

So my guess now, is maybe it's a difference in years thing. The early models didn't have them and the later ones did?

Just throwing out some guesses, I really have no idea! 

[OldSwartout]

Those are typically for ejection pins in the molds to help push the castings out.  It may be that there was a change made to improve the casting process or there may have been two sources, one that used the ejection pins and one that didn't. 

BTW, 175 cylinders don't have the "cutouts", but the 200s do.  It seems to be a sure way of telling a 175 from a 200 just with a quick glance.

[Mike Anderson]

Hi All,
It is interesting to me, what I noticed after the discussion started. I have several bikes and most of them have the cutouts. The interesting part is my NOS cylinders do not have the cutouts. That is kind of hard to understand since my other bikes range from very early to very late and they have the cutouts. Almost makes you want to believe they might have had a supplier making replacement parts and a production line supplier. Who knows just thought I would put that out there.
Later Mike

[moonpup]

Well...........so much for my guesses!     

It's starting to look more like production supplier vs. replacement supplier, with production guys having the cut outs and the replacement suppliers not.

[old smokey]

No help here. My '67 GTR does not have the cut-outs, but I have no idea about the history of the engine before 1980. The heads might be original, they might not...?