https://www.armoursltd.co.uk/product/mo ... -pipe-set/
"Moto Morini 3-1/2 – Pipe Set
£191.00
Moto Morini 3-1/2 Stainless Steel Pipe set, these pipes have reductions at the cylinder head for collets, for early kick start models. Outside diameter 32mm
Our stainless steel pipes are made from Grade 304 stainless steel. The advantage of stainless steel is that it will not rot even when neglected. Some yellowing and discoloration may occur on how hot the pipe gets, periodic polishing will restore the product back to as new appearance."