Yamaha SR - Header Pipe - Standard High quality stainless steel standard header pipe $76.00 Unfortunately this product is currently out of stock. Please contact us for more information. This high quality stainless steel header pipe follows the lines of the original pipe, but differs in 2 ways: - it is single walled, unlike the double walled original pipe - it is much lighter than the original The outlet diameter is 42mm. It can be fitted with the original muffler or one of our custom mufflers. (see product suggestion below) The pipe comes with a stainless steel mounting flange.