Difference between exhaust pipes

[Peter_plade]

I bought a couple of used right side exhausts for my 76 550, but noticed that they weren't 100% identical.
If I look in the end of the pipes, the 2 left ones that is original to the bike has a center hole and smaller holes around it, the 2 right side only has the center hole. Why is that? And does make any difference?

[Johnwebley]

if you look at the top pic,the added holes are not uniform,and appear to have been added by the
previous owner

[Peter_plade]

You are right hadn't noticed that, guess I will have to fire up the welder.

[matthewmosse]

I had a mate who used to bodge extra holes like that to 'increase power' by bypassing or destroying the backpressure. I would weld it up if I were you. Might make the bike louder but especially if just done to one could just screw up the jetting and carb balance.